Java Jackson API：部分更新字符串_Java_Json_Serialization_Jackson_Deserialization

Java Jackson API：部分更新字符串

java json serialization

Java Jackson API：部分更新字符串,java,json,serialization,jackson,deserialization,Java,Json,Serialization,Jackson,Deserialization,我有一个非常复杂的Json对象，它是作为字符串获取的： { "a": ..., "b":..., /* lots of other properties */ "z":... } 我与Jackson一起阅读了部分内容，并将其映射到Java类： class PartialObjectForB { @JsonProperty("b") private ObjectB b; } 我使用ObjectMapper类中的readValue（）方法并得到我想要的。。。到目前为止，一切顺利现在，我想更新P

我有一个非常复杂的Json对象，它是作为字符串获取的：

{ "a": ..., "b":..., /* lots of other properties */ "z":... }

我与Jackson一起阅读了部分内容，并将其映射到Java类：

class PartialObjectForB { @JsonProperty("b") private ObjectB b; }

我使用ObjectMapper类中的readValue（）方法并得到我想要的。。。到目前为止，一切顺利

现在，我想更新PartialObjectForB中的一些值，并更新我拥有的初始字符串。我想到了如何用jackson更新Java对象（通过使用readerforupdate），但找不到相反的方法：用Java对象更新Json对象/字符串

我知道如何使用JSONObject快速解决这个问题。例如，如果我只想更新1个值：

JSONObject j = new JSONObject(/* the full json string */);
j.getJSONObject("b").getJSONObject("bb")/* etc. */.put("bbbb", 4);
j.toString(); // will give me the full original text with only "b" updated.

但我找不到如何与杰克逊合作

有什么想法吗

注:

我的输入/输出是字符串，无法更改
我不知道json对象中有什么数据。我只知道我可能有属性“b”，如果我没有，我可以创建它
我可能希望在根级别反序列化和更新多个属性（例如：“b”、“h”和“w”）
这个问题不是递归的。意思是：我有一个我取消序列化的值的完整表示（没有未知属性）
json对象作为一个字符串，由几千个字节组成，但我想要更新的部分通常要小得多（例如：大约100个字节）

我能想到的最简单的解决方案是将JSON反序列化到

Map

类中（例如LinkedHashMap）。请参见下面的示例：

import java.util.LinkedHashMap;

import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonProgram {

    public static void main(String[] args) throws Exception {
        ObjectMapper mapper = new ObjectMapper();

        String json = "{\"a\":\"java.lang.Integer\",\"b\":\"time json\",\"c\":\"action json\",\"d\":[1,2,3]}";
        System.out.println(json);

        LinkedHashMap<String, Object> map = mapper.readValue(json, LinkedHashMap.class);
        map.put("b", "Override property or create new");

        System.out.println(mapper.writeValueAsString(map));
    }
}

如果要更改路径的内部属性，可以通过以下方式实现：

import java.io.IOException;
import java.util.Arrays;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedList;

import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonProgram {

    public static void main(String[] args) throws IOException {
        ObjectMapper mapper = new ObjectMapper();

        String json = "{\"b\":{\"bb\":{\"bbb\":20}}}";
        System.out.println(json);

        LinkedHashMap<String, Object> map = mapper.readValue(json, LinkedHashMap.class);
        JsonUpdater updater = new JsonUpdater(map);
        updater.update(Arrays.asList("b", "bb", "bbb"), 4);

        System.out.println(mapper.writeValueAsString(map));
    }
}

class JsonUpdater {

    private LinkedHashMap<String, Object> jsonMap;

    public JsonUpdater(LinkedHashMap<String, Object> jsonMap) {
        this.jsonMap = jsonMap;
    }

    public boolean update(Collection<String> propertiesOnThePath, Object newValue) {
        LinkedList<String> path = new LinkedList<String>(propertiesOnThePath);
        String lastProperty = path.removeLast();

        LinkedHashMap<String, Object> objectMap = jsonMap;
        while (!path.isEmpty()) {
            String property = path.poll();
            if (!objectMap.containsKey(property)) {
                return false;
            }

            objectMap = (LinkedHashMap<String, Object>) objectMap.get(property);
        }

        if (!objectMap.containsKey(lastProperty)) {
            return false;
        }

        objectMap.put(lastProperty, newValue);

        return false;
    }
}

正如我们所看到的：值被改变了。但是这个解决方案有很大的缺点——我们必须反序列化所有JSON。几千字节的字符串对于Java来说不是问题，但是如果您真的想优化您的程序，您可以使用

ObjectNode

类和

ObjectMapper\readTree

方法。请参阅以下源代码：

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;

public class JacksonProgram {

    public static void main(String[] args) throws Exception {
        ObjectMapper mapper = new ObjectMapper();

        String json = "{\"a\":\"java.lang.Integer\",\"b\":\"time json\",\"c\":\"action json\",\"d\":[1,2,3]}";
        System.out.println(json);

        ObjectNode jsonTree = (ObjectNode) mapper.readTree(json);
        jsonTree.put("b", "Override property or create new");
        System.out.println(jsonTree.toString());
    }
}

以上程序打印：

{"a":"java.lang.Integer","b":"time json","c":"action json","d":[1,2,3]}
{"a":"java.lang.Integer","b":"Override property or create new","c":"action json","d":[1,2,3]}

{"b":{"bb":{"bbb":20}}}
{"b":{"bb":{"bbb":4}}}

{"a":"java.lang.Integer","b":"time json","c":"action json","d":[1,2,3]}
{"a":"java.lang.Integer","b":"Override property or create new","c":"action json","d":[1,2,3]}

我没有做任何比较测试，但您可以测试哪种解决方案对您更有效。

胜利！：）我现在有了它的一个实现，它不是很简单。包括基准测试Jackson vs JSONObject

问题和解决方案逐条描述：

首先，我在一个数据存储中有一个很大的json字符串，我想对其进行部分反序列化和更新。反序列化必须是部分的，但序列化已满，因此我不会丢失未反序列化的数据。以下是我在示例中使用的对象：

   private static class KnownPart {

        @JsonProperty
        private Customer customer;
        @JsonProperty
        private BrowserInfo browser;
    }

    private static class Customer {

        @JsonProperty
        private int id;
        @JsonProperty
        private String name;
        @JsonProperty
        private Address[] addresses; // just to make it more complex for this example

        public Customer(int id, String name, Address[] addresses) {
            this.id = id;
            this.name = name;
            this.addresses = addresses;
        }

        public Customer() {
        }
    }

    private static class Address {

        @JsonProperty
        private String street;
        @JsonProperty
        private String city;

        public Address(String street, String city) {
            this.street = street;
            this.city = city;
        }

        public Address() {
        }
    }

    private static class BrowserInfo {

        @JsonProperty
        private String agent;
        @JsonProperty
        private String version;

        public BrowserInfo(String agent, String version) {
            this.agent = agent;
            this.version = version;
        }

        public BrowserInfo() {
        }
    }

KnownPart对象包含的属性远不止2个，但我不知道到底是哪些属性，我不能保证跟踪哪些属性添加到json字符串中

我有一个数据存储，它的数据用Json编码。当前的实现使用JSONObject进行读/写，并支持jackson读取json并将其映射到“真实”Java对象（POJO和更复杂的对象）。虽然使用jackson编写完整的Json字符串不是问题，但是使用只表示字符串一小部分的Java对象更新现有字符串要困难得多

数据存储问题：

    private static class DataStore {

        private final String data;

        private DataStore(Customer customer, BrowserInfo browser) throws IOException, JSONException {
            StringWriter sw = new StringWriter(1000);
            try (JsonGenerator jgen = MAPPER.getJsonFactory().createJsonGenerator(sw)) {
                jgen.writeStartObject();
                writeBunchOfProperties(jgen);
                jgen.writeFieldName("customer");
                jgen.writeRawValue(MAPPER.writeValueAsString(customer));
                writeBunchOfProperties(jgen);
                jgen.writeFieldName("browser");
                jgen.writeRawValue(MAPPER.writeValueAsString(browser));
                writeBunchOfProperties(jgen);
                jgen.writeEndObject();
            }
            this.data = sw.toString();
        }

        private void writeBunchOfProperties(JsonGenerator jgen) throws IOException {
            int c = new Random().nextInt(3) + 1;
            for (int i = 0; i < c; ++i) {
                jgen.writeFieldName(RandomStringUtils.random(10));
                jgen.writeRawValue(JSON_LONG);
            }
        }

        public String readData(String query) {
            return data;
        }

        private void saveData(String json) {
            // Not implemented
        }

        public void saveData(JSONObject json) {
            saveData(json.toString());
        }

        public void saveData(Object obj) throws IOException {
            // problem: ?
        }

        public <T> T readData(String query, Class<T> clazz) throws IOException {
            return MAPPER.readValue(readData(query), clazz);
        }

        public <T> T readDataForUpdating(String query, Class<T> clazz) throws IOException {
            // problem: ?
        }

不会丢失保存时未读取的数据。显然，我不想第二次读取数据，因为我正在从远程主机读取数据，我不想将其缓存在某个静态/实例映射中，因为我需要在高度并发的环境中仍然非常有效

因此，简单地说，解决方案是： -首先读取json字符串的树，并使用它将json对象反序列化为Java对象。 -存储反序列化对象（在KnowPart类中）并将树存储在某个父抽象类中 -编写一个Jackson模块来定制bean的序列化方式。该代码与原始代码几乎相同，不同之处在于，当写入KnownPart中的属性时，它的键被从UnknownPart对象中的树中移除，然后就可以轻松地写入未知部分
主要目标是：

private static abstract class UnknownPart { ObjectNode tree; } private static class KnownPart extends UnknownPart { @JsonProperty private Customer customer; @JsonProperty private BrowserInfo browser; }
该模块仅处理未知零件对象：私有静态类MyModule扩展模块{

@Override public String getModuleName() { return "MyModule"; } @Override public Version version() { return new Version(0, 0, 1, "SNAPSHOT"); } @Override public void setupModule(Module.SetupContext context) { context.addBeanSerializerModifier(new org.codehaus.jackson.map.ser.BeanSerializerModifier() { private UnknownPartSerializer cs; @Override public JsonSerializer modifySerializer(SerializationConfig config, BasicBeanDescription beanDesc, JsonSerializer<?> serializer) { return UnknownPart.class.isAssignableFrom(beanDesc.getBeanClass()) ? new UnknownPartSerializer((BeanSerializerBase) serializer) : serializer; } }); } }

包含基准测试的完整可执行源代码为：

import java.io.IOException; import java.io.StringWriter; import java.util.Iterator; import java.util.Map.Entry; import java.util.Random; import org.apache.commons.lang3.RandomStringUtils; import org.apache.commons.lang3.StringUtils; import org.codehaus.jackson.JsonGenerationException; import org.codehaus.jackson.JsonGenerator; import org.codehaus.jackson.JsonNode; import org.codehaus.jackson.Version; import org.codehaus.jackson.annotate.JsonProperty; import org.codehaus.jackson.map.DeserializationConfig; import org.codehaus.jackson.map.JsonMappingException; import org.codehaus.jackson.map.JsonSerializer; import org.codehaus.jackson.map.Module; import org.codehaus.jackson.map.ObjectMapper; import org.codehaus.jackson.map.SerializationConfig; import org.codehaus.jackson.map.SerializerProvider; import org.codehaus.jackson.map.introspect.BasicBeanDescription; import org.codehaus.jackson.map.ser.BeanPropertyWriter; import org.codehaus.jackson.map.ser.std.BeanSerializerBase; import org.codehaus.jackson.node.ObjectNode; import org.json.JSONException; import org.json.JSONObject; public class JacksonModule { private static final ObjectMapper MAPPER = new ObjectMapper(); private static final int COUNT = 0; private static final int REPEAT_HEADER = 40; static { MAPPER.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false); MAPPER.configure(SerializationConfig.Feature.WRITE_NULL_PROPERTIES, false); MAPPER.registerModule(new MyModule()); } private DataProcessor sdp; private long[] sum = new long[5]; public static void main(String[] args) throws IOException, JSONException { new JacksonModule().start(); } public JacksonModule() throws IOException, JSONException { this.sdp = new DataProcessor(); } public void start() throws IOException, JSONException { run(-1, false); // load classes: slow if (COUNT > 0) { for (int i = 0; i < COUNT; ++i) { if (i % REPEAT_HEADER == 0) { System.out.println("---------------------------------------------------------------------------------------"); print("", "RO JSONObject", "RO Jackson", "R/- Jackson", "R/W JSONObject", "R/W Jackson"); System.out.println("---------------------------------------------------------------------------------------"); } run(i, true); } System.out.println("-- AVERAGE ----------------------------------------------------------------------------"); print(1, sum[0] / COUNT, sum[1] / COUNT, sum[2] / COUNT, sum[3] / COUNT, sum[4] / COUNT); System.out.println("---------------------------------------------------------------------------------------"); print("", "RO JSONObject", "RO Jackson", "R/- Jackson", "R/W JSONObject", "R/W Jackson"); System.out.println("---------------------------------------------------------------------------------------"); } } public void run(int i, boolean print) throws JSONException, IOException { long t1 = sdp.doReadWithJSONObject(); long t2 = sdp.doReadWithJackson(); long t3 = sdp.doReadForUpdatingWithJacksonButDontWrite(); long t4 = sdp.doSomeWritingWithJSONObject(); long t5 = sdp.doSomeWritingWithJackson(); if (print) { print(i, t1, t2, t3, t4, t5); sum[0] += t1; sum[1] += t2; sum[2] += t3; sum[3] += t4; sum[4] += t5; } } private void print(int index, long t1, long t2, long t3, long t4, long t5) { print(Integer.toString(index), String.format("%,d", t1), String.format("%,d", t2), String.format("%,d", t3), String.format("%,d", t4), String.format("%,d", t5)); } private void print(String i0, String a, String b, String c, String d, String e) { System.out.println("|" + StringUtils.leftPad(i0, 5) + "|" + StringUtils.leftPad(a, 15) + "|" + StringUtils.leftPad(b, 15) + "|" + StringUtils.leftPad(c, 15) + "|" + StringUtils.leftPad(d, 15) + "|" + StringUtils.leftPad(e, 15) + "|"); } private static class DataProcessor { private DataStore store; private long t0, t1; private DataProcessor() throws IOException, JSONException { this.store = new DataStore(customer, browser); } public long doReadWithJSONObject() throws JSONException { t0 = System.nanoTime(); JSONObject json = new JSONObject(store.readData(null)); // can throw JSONException JSONObject customer = json.getJSONObject("customer"); // can throw JSONException JSONObject browserInfo = json.getJSONObject("browser"); // can throw JSONException // need to do manually the mapping and figure out what is exactly in this object. Hell no! t1 = System.nanoTime(); return t1 - t0; } public long doReadWithJackson() throws IOException { t0 = System.nanoTime(); KnownPart obj = store.readData(null, KnownPart.class); t1 = System.nanoTime(); return t1 - t0; } public long doReadForUpdatingWithJacksonButDontWrite() throws IOException { t0 = System.nanoTime(); KnownPart obj = store.readDataForUpdating(null, KnownPart.class); t1 = System.nanoTime(); return t1 - t0; } public long doSomeWritingWithJSONObject() throws JSONException { t0 = System.nanoTime(); JSONObject json = new JSONObject(store.readData(null)); // can throw JSONException JSONObject customer = json.getJSONObject("customer"); // can throw JSONException JSONObject browserInfo = json.getJSONObject("browser"); // can throw JSONException customer.put("name", "Jackson Doe"); browserInfo.put("version", "10"); store.saveData(json); t1 = System.nanoTime(); return t1 - t0; } public long doSomeWritingWithJackson() throws IOException { t0 = System.nanoTime(); KnownPart obj = store.readDataForUpdating(null, KnownPart.class); obj.customer.name = "Jackson Doe"; obj.browser.version = "10"; store.saveData(obj); t1 = System.nanoTime(); return t1 - t0; } } private static class DataStore { private final String data; private DataStore(Customer customer, BrowserInfo browser) throws IOException, JSONException { StringWriter sw = new StringWriter(1000); try (JsonGenerator jgen = MAPPER.getJsonFactory().createJsonGenerator(sw)) { jgen.writeStartObject(); writeBunchOfProperties(jgen); jgen.writeFieldName("customer"); jgen.writeRawValue(MAPPER.writeValueAsString(customer)); writeBunchOfProperties(jgen); jgen.writeFieldName("browser"); jgen.writeRawValue(MAPPER.writeValueAsString(browser)); writeBunchOfProperties(jgen); jgen.writeEndObject(); } this.data = sw.toString(); } private void writeBunchOfProperties(JsonGenerator jgen) throws IOException { int c = new Random().nextInt(3) + 1; for (int i = 0; i < c; ++i) { jgen.writeFieldName(RandomStringUtils.random(10)); jgen.writeRawValue(JSON_LONG); } } public String readData(String query) { return data; } private void saveData(String json) { // TODO } public void saveData(JSONObject json) { saveData(json.toString()); } public void saveData(Object obj) throws IOException { saveData(MAPPER.writeValueAsString(obj)); } public <T> T readData(String query, Class<T> clazz) throws IOException { return MAPPER.readValue(readData(query), clazz); } public <T extends UnknownPart> T readDataForUpdating(String query, Class<T> clazz) throws IOException { ObjectNode root = (ObjectNode) MAPPER.readTree(readData(query)); T obj = MAPPER.readValue(root, clazz); obj.tree = root; return obj; } } private static abstract class UnknownPart { ObjectNode tree; } private static class KnownPart extends UnknownPart { @JsonProperty private Customer customer; @JsonProperty private BrowserInfo browser; } private static class Customer { @JsonProperty private int id; @JsonProperty private String name; @JsonProperty private Address[] addresses; // just to make it more complex for this example public Customer(int id, String name, Address[] addresses) { this.id = id; this.name = name; this.addresses = addresses; } public Customer() { } } private static class Address { @JsonProperty private String street; @JsonProperty private String city; public Address(String street, String city) { this.street = street; this.city = city; } public Address() { } } private static class BrowserInfo { @JsonProperty private String agent; @JsonProperty private String version; public BrowserInfo(String agent, String version) { this.agent = agent; this.version = version; } public BrowserInfo() { } } private static class MyModule extends Module { @Override public String getModuleName() { return "MyModule"; } @Override public Version version() { return new Version(0, 0, 1, "SNAPSHOT"); } @Override public void setupModule(Module.SetupContext context) { context.addBeanSerializerModifier(new org.codehaus.jackson.map.ser.BeanSerializerModifier() { private UnknownPartSerializer cs; @Override public JsonSerializer modifySerializer(SerializationConfig config, BasicBeanDescription beanDesc, JsonSerializer<?> serializer) { return UnknownPart.class.isAssignableFrom(beanDesc.getBeanClass()) ? new UnknownPartSerializer((BeanSerializerBase) serializer) : serializer; } }); } } private static class UnknownPartSerializer extends BeanSerializerBase { public UnknownPartSerializer(BeanSerializerBase src) { super(src); } @Override public void serialize(Object bean, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonGenerationException { UnknownPart up = (UnknownPart) bean; jgen.writeStartObject(); serializeFields(up, jgen, provider); jgen.writeEndObject(); } protected void serializeFields(UnknownPart bean, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonGenerationException { final BeanPropertyWriter[] props; if (_filteredProps != null && provider.getSerializationView() != null) { props = _filteredProps; } else { props = _props; } int i = 0; try { for (final int len = props.length; i < len; ++i) { BeanPropertyWriter prop = props[i]; if (prop != null) { // can have nulls in filtered list prop.serializeAsField(bean, jgen, provider); bean.tree.remove(prop.getName()); } } if (_anyGetterWriter != null) { _anyGetterWriter.getAndSerialize(bean, jgen, provider); } Iterator<Entry<String, JsonNode>> it = bean.tree.getFields(); while (it.hasNext()) { Entry<String, JsonNode> e = it.next(); jgen.writeFieldName(e.getKey()); jgen.writeObject(e.getValue()); } } catch (Exception e) { String name = (i == props.length) ? "[anySetter]" : props[i].getName(); wrapAndThrow(provider, e, bean, name); } catch (StackOverflowError e) { /* 04-Sep-2009, tatu: Dealing with this is tricky, since we do not * have many stack frames to spare... just one or two; can't * make many calls. */ JsonMappingException mapE = new JsonMappingException("Infinite recursion (StackOverflowError)", e); String name = (i == props.length) ? "[anySetter]" : props[i].getName(); mapE.prependPath(new JsonMappingException.Reference(bean, name)); throw mapE; } } } private static Customer customer = new Customer(1, "John Doe", new Address[]{ new Address("broadway av", "new york"), new Address("peachtree st", "atlanta") }); private static BrowserInfo browser = new BrowserInfo("IE", "6.0"); // some json found on the internet private static final String JSON_LONG = "{\"web-app\": {" + "\"servlet\": [" + "{" + "\"servlet-name\": \"cofaxCDS\"," + "\"servlet-class\": \"org.cofax.cds.CDSServlet\"," + "\"init-param\": {" + "\"configGlossary:installationAt\": \"Philadelphia, PA\"," + "\"configGlossary:adminEmail\": \"ksm@pobox.com\"," + "\"configGlossary:poweredBy\": \"Cofax\"," + "\"configGlossary:poweredByIcon\": \"/images/cofax.gif\"," + "\"configGlossary:staticPath\": \"/content/static\"," + "\"templateProcessorClass\": \"org.cofax.WysiwygTemplate\"," + "\"templateLoaderClass\": \"org.cofax.FilesTemplateLoader\"," + "\"templatePath\": \"templates\"," + "\"templateOverridePath\": \"\"," + "\"defaultListTemplate\": \"listTemplate.htm\"," + "\"defaultFileTemplate\": \"articleTemplate.htm\"," + "\"useJSP\": false," + "\"jspListTemplate\": \"listTemplate.jsp\"," + "\"jspFileTemplate\": \"articleTemplate.jsp\"," + "\"cachePackageTagsTrack\": 200," + "\"cachePackageTagsStore\": 200," + "\"cachePackageTagsRefresh\": 60," + "\"cacheTemplatesTrack\": 100," + "\"cacheTemplatesStore\": 50," + "\"cacheTemplatesRefresh\": 15," + "\"cachePagesTrack\": 200," + "\"cachePagesStore\": 100," + "\"cachePagesRefresh\": 10," + "\"cachePagesDirtyRead\": 10," + "\"searchEngineListTemplate\": \"forSearchEnginesList.htm\"," + "\"searchEngineFileTemplate\": \"forSearchEngines.htm\"," + "\"searchEngineRobotsDb\": \"WEB-INF/robots.db\"," + "\"useDataStore\": true," + "\"dataStoreClass\": \"org.cofax.SqlDataStore\"," + "\"redirectionClass\": \"org.cofax.SqlRedirection\"," + "\"dataStoreName\": \"cofax\"," + "\"dataStoreDriver\": \"com.microsoft.jdbc.sqlserver.SQLServerDriver\"," + "\"dataStoreUrl\": \"jdbc:microsoft:sqlserver://LOCALHOST:1433;DatabaseName=goon\"," + "\"dataStoreUser\": \"sa\"," + "\"dataStorePassword\": \"dataStoreTestQuery\"," + "\"dataStoreTestQuery\": \"SET NOCOUNT ON;select test='test';\"," + "\"dataStoreLogFile\": \"/usr/local/tomcat/logs/datastore.log\"," + "\"dataStoreInitConns\": 10," + "\"dataStoreMaxConns\": 100," + "\"dataStoreConnUsageLimit\": 100," + "\"dataStoreLogLevel\": \"debug\"," + "\"maxUrlLength\": 500}}," + "{" + "\"servlet-name\": \"cofaxEmail\"," + "\"servlet-class\": \"org.cofax.cds.EmailServlet\"," + "\"init-param\": {" + "\"mailHost\": \"mail1\"," + "\"mailHostOverride\": \"mail2\"}}," + "{" + "\"servlet-name\": \"cofaxAdmin\"," + "\"servlet-class\": \"org.cofax.cds.AdminServlet\"}," + "" + "{" + "\"servlet-name\": \"fileServlet\"," + "\"servlet-class\": \"org.cofax.cds.FileServlet\"}," + "{" + "\"servlet-name\": \"cofaxTools\"," + "\"servlet-class\": \"org.cofax.cms.CofaxToolsServlet\"," + "\"init-param\": {" + "\"templatePath\": \"toolstemplates/\"," + "\"log\": 1," + "\"logLocation\": \"/usr/local/tomcat/logs/CofaxTools.log\"," + "\"logMaxSize\": \"\"," + "\"dataLog\": 1," + "\"dataLogLocation\": \"/usr/local/tomcat/logs/dataLog.log\"," + "\"dataLogMaxSize\": \"\"," + "\"removePageCache\": \"/content/admin/remove?cache=pages&id=\"," + "\"removeTemplateCache\": \"/content/admin/remove?cache=templates&id=\"," + "\"fileTransferFolder\": \"/usr/local/tomcat/webapps/content/fileTransferFolder\"," + "\"lookInContext\": 1," + "\"adminGroupID\": 4," + "\"betaServer\": true}}]," + "\"servlet-mapping\": {" + "\"cofaxCDS\": \"/\"," + "\"cofaxEmail\": \"/cofaxutil/aemail/*\"," + "\"cofaxAdmin\": \"/admin/*\"," + "\"fileServlet\": \"/static/*\"," + "\"cofaxTools\": \"/tools/*\"}," + "" + "\"taglib\": {" + "\"taglib-uri\": \"cofax.tld\"," + "\"taglib-location\": \"/WEB-INF/tlds/cofax.tld\"}}}"; }

import java.io.IOException；导入java.io.StringWriter；导入java.util.Iterator；导入java.util.Map.Entry；导入java.util.Random；导入org.apache.commons.lang3.RandomStringUtils；导入org.apache.commons.lang3.StringUtils；导入org.codehaus.jackson.jsongGenerationException；导入org.codehaus.jackson.jsonggenerator；导入org.codehaus.jackson.JsonNode；导入org.codehaus.jackson.Version；导入org.codehaus.jackson.annotate.JsonProperty；导入org.codehaus.jackson.map.DeserializationConfig；导入org.codehaus.jackson.map.JsonMappingException；导入org.codehaus.jackson.map.JsonSerializer；导入org.codehaus.jackson.map.Module；导入org.codehaus.jackson.map.ObjectMapper；导入org.codehaus.jackson.map.SerializationConfig；导入org.codehaus.jackson.map.SerializerProvider；导入org.codehaus.jackson.map.introspect.BasicBeanDescription；导入org.codehaus.jackson.map.ser.BeanPropertyWriter；导入org.codehaus.jackson.map.ser.std.beanserializarbase；导入org.codehaus.jackson.node.ObjectNode；导入org.json.JSONException；导入org.json.JSONObject；公共类JacksonModule{ 私有静态最终ObjectMapper MAPPER=新ObjectMapper（）；私有静态最终整数计数=0；专用静态最终int REPEAT_头=40；静止的{ configure（在未知属性上反序列化config.Feature.FAIL，false）； configure（SerializationConfig.Feature.WRITE\u NULL\u属性，false）； registerModule（新的MyModule（））； } 专用数据处理器；私有长[]和=新长[5]；公共静态void main（字符串[]args）抛出IOException、JSONException{ 新JacksonModule（）.start（）； } 公共JacksonModule（）抛出IOException，JSONException{ this.sdp=新的数据处理程序 private static class UnknownPartSerializer extends BeanSerializerBase { public UnknownPartSerializer(BeanSerializerBase src) { super(src); } @Override public void serialize(Object bean, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonGenerationException { UnknownPart up = (UnknownPart) bean; jgen.writeStartObject(); serializeFields(up, jgen, provider); jgen.writeEndObject(); } protected void serializeFields(UnknownPart bean, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonGenerationException { final BeanPropertyWriter[] props; if (_filteredProps != null && provider.getSerializationView() != null) { props = _filteredProps; } else { props = _props; } int i = 0; try { for (final int len = props.length; i < len; ++i) { BeanPropertyWriter prop = props[i]; if (prop != null) { // can have nulls in filtered list prop.serializeAsField(bean, jgen, provider); bean.tree.remove(prop.getName()); // new } } if (_anyGetterWriter != null) { _anyGetterWriter.getAndSerialize(bean, jgen, provider); } // new: Iterator<Entry<String, JsonNode>> it = bean.tree.getFields(); while (it.hasNext()) { Entry<String, JsonNode> e = it.next(); jgen.writeFieldName(e.getKey()); jgen.writeObject(e.getValue()); } } catch (Exception e) { String name = (i == props.length) ? "[anySetter]" : props[i].getName(); wrapAndThrow(provider, e, bean, name); } catch (StackOverflowError e) { /* 04-Sep-2009, tatu: Dealing with this is tricky, since we do not * have many stack frames to spare... just one or two; can't * make many calls. */ JsonMappingException mapE = new JsonMappingException("Infinite recursion (StackOverflowError)", e); String name = (i == props.length) ? "[anySetter]" : props[i].getName(); mapE.prependPath(new JsonMappingException.Reference(bean, name)); throw mapE; } } } -- AVERAGE ---------------------------------------------------------------------------- | 1| 860,560| 157,772| 234,654| 1,595,018| 488,427| --------------------------------------------------------------------------------------- | | RO JSONObject| RO Jackson| R/- Jackson| R/W JSONObject| R/W Jackson| --------------------------------------------------------------------------------------- import java.io.IOException; import java.io.StringWriter; import java.util.Iterator; import java.util.Map.Entry; import java.util.Random; import org.apache.commons.lang3.RandomStringUtils; import org.apache.commons.lang3.StringUtils; import org.codehaus.jackson.JsonGenerationException; import org.codehaus.jackson.JsonGenerator; import org.codehaus.jackson.JsonNode; import org.codehaus.jackson.Version; import org.codehaus.jackson.annotate.JsonProperty; import org.codehaus.jackson.map.DeserializationConfig; import org.codehaus.jackson.map.JsonMappingException; import org.codehaus.jackson.map.JsonSerializer; import org.codehaus.jackson.map.Module; import org.codehaus.jackson.map.ObjectMapper; import org.codehaus.jackson.map.SerializationConfig; import org.codehaus.jackson.map.SerializerProvider; import org.codehaus.jackson.map.introspect.BasicBeanDescription; import org.codehaus.jackson.map.ser.BeanPropertyWriter; import org.codehaus.jackson.map.ser.std.BeanSerializerBase; import org.codehaus.jackson.node.ObjectNode; import org.json.JSONException; import org.json.JSONObject; public class JacksonModule { private static final ObjectMapper MAPPER = new ObjectMapper(); private static final int COUNT = 0; private static final int REPEAT_HEADER = 40; static { MAPPER.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES, false); MAPPER.configure(SerializationConfig.Feature.WRITE_NULL_PROPERTIES, false); MAPPER.registerModule(new MyModule()); } private DataProcessor sdp; private long[] sum = new long[5]; public static void main(String[] args) throws IOException, JSONException { new JacksonModule().start(); } public JacksonModule() throws IOException, JSONException { this.sdp = new DataProcessor(); } public void start() throws IOException, JSONException { run(-1, false); // load classes: slow if (COUNT > 0) { for (int i = 0; i < COUNT; ++i) { if (i % REPEAT_HEADER == 0) { System.out.println("---------------------------------------------------------------------------------------"); print("", "RO JSONObject", "RO Jackson", "R/- Jackson", "R/W JSONObject", "R/W Jackson"); System.out.println("---------------------------------------------------------------------------------------"); } run(i, true); } System.out.println("-- AVERAGE ----------------------------------------------------------------------------"); print(1, sum[0] / COUNT, sum[1] / COUNT, sum[2] / COUNT, sum[3] / COUNT, sum[4] / COUNT); System.out.println("---------------------------------------------------------------------------------------"); print("", "RO JSONObject", "RO Jackson", "R/- Jackson", "R/W JSONObject", "R/W Jackson"); System.out.println("---------------------------------------------------------------------------------------"); } } public void run(int i, boolean print) throws JSONException, IOException { long t1 = sdp.doReadWithJSONObject(); long t2 = sdp.doReadWithJackson(); long t3 = sdp.doReadForUpdatingWithJacksonButDontWrite(); long t4 = sdp.doSomeWritingWithJSONObject(); long t5 = sdp.doSomeWritingWithJackson(); if (print) { print(i, t1, t2, t3, t4, t5); sum[0] += t1; sum[1] += t2; sum[2] += t3; sum[3] += t4; sum[4] += t5; } } private void print(int index, long t1, long t2, long t3, long t4, long t5) { print(Integer.toString(index), String.format("%,d", t1), String.format("%,d", t2), String.format("%,d", t3), String.format("%,d", t4), String.format("%,d", t5)); } private void print(String i0, String a, String b, String c, String d, String e) { System.out.println("|" + StringUtils.leftPad(i0, 5) + "|" + StringUtils.leftPad(a, 15) + "|" + StringUtils.leftPad(b, 15) + "|" + StringUtils.leftPad(c, 15) + "|" + StringUtils.leftPad(d, 15) + "|" + StringUtils.leftPad(e, 15) + "|"); } private static class DataProcessor { private DataStore store; private long t0, t1; private DataProcessor() throws IOException, JSONException { this.store = new DataStore(customer, browser); } public long doReadWithJSONObject() throws JSONException { t0 = System.nanoTime(); JSONObject json = new JSONObject(store.readData(null)); // can throw JSONException JSONObject customer = json.getJSONObject("customer"); // can throw JSONException JSONObject browserInfo = json.getJSONObject("browser"); // can throw JSONException // need to do manually the mapping and figure out what is exactly in this object. Hell no! t1 = System.nanoTime(); return t1 - t0; } public long doReadWithJackson() throws IOException { t0 = System.nanoTime(); KnownPart obj = store.readData(null, KnownPart.class); t1 = System.nanoTime(); return t1 - t0; } public long doReadForUpdatingWithJacksonButDontWrite() throws IOException { t0 = System.nanoTime(); KnownPart obj = store.readDataForUpdating(null, KnownPart.class); t1 = System.nanoTime(); return t1 - t0; } public long doSomeWritingWithJSONObject() throws JSONException { t0 = System.nanoTime(); JSONObject json = new JSONObject(store.readData(null)); // can throw JSONException JSONObject customer = json.getJSONObject("customer"); // can throw JSONException JSONObject browserInfo = json.getJSONObject("browser"); // can throw JSONException customer.put("name", "Jackson Doe"); browserInfo.put("version", "10"); store.saveData(json); t1 = System.nanoTime(); return t1 - t0; } public long doSomeWritingWithJackson() throws IOException { t0 = System.nanoTime(); KnownPart obj = store.readDataForUpdating(null, KnownPart.class); obj.customer.name = "Jackson Doe"; obj.browser.version = "10"; store.saveData(obj); t1 = System.nanoTime(); return t1 - t0; } } private static class DataStore { private final String data; private DataStore(Customer customer, BrowserInfo browser) throws IOException, JSONException { StringWriter sw = new StringWriter(1000); try (JsonGenerator jgen = MAPPER.getJsonFactory().createJsonGenerator(sw)) { jgen.writeStartObject(); writeBunchOfProperties(jgen); jgen.writeFieldName("customer"); jgen.writeRawValue(MAPPER.writeValueAsString(customer)); writeBunchOfProperties(jgen); jgen.writeFieldName("browser"); jgen.writeRawValue(MAPPER.writeValueAsString(browser)); writeBunchOfProperties(jgen); jgen.writeEndObject(); } this.data = sw.toString(); } private void writeBunchOfProperties(JsonGenerator jgen) throws IOException { int c = new Random().nextInt(3) + 1; for (int i = 0; i < c; ++i) { jgen.writeFieldName(RandomStringUtils.random(10)); jgen.writeRawValue(JSON_LONG); } } public String readData(String query) { return data; } private void saveData(String json) { // TODO } public void saveData(JSONObject json) { saveData(json.toString()); } public void saveData(Object obj) throws IOException { saveData(MAPPER.writeValueAsString(obj)); } public <T> T readData(String query, Class<T> clazz) throws IOException { return MAPPER.readValue(readData(query), clazz); } public <T extends UnknownPart> T readDataForUpdating(String query, Class<T> clazz) throws IOException { ObjectNode root = (ObjectNode) MAPPER.readTree(readData(query)); T obj = MAPPER.readValue(root, clazz); obj.tree = root; return obj; } } private static abstract class UnknownPart { ObjectNode tree; } private static class KnownPart extends UnknownPart { @JsonProperty private Customer customer; @JsonProperty private BrowserInfo browser; } private static class Customer { @JsonProperty private int id; @JsonProperty private String name; @JsonProperty private Address[] addresses; // just to make it more complex for this example public Customer(int id, String name, Address[] addresses) { this.id = id; this.name = name; this.addresses = addresses; } public Customer() { } } private static class Address { @JsonProperty private String street; @JsonProperty private String city; public Address(String street, String city) { this.street = street; this.city = city; } public Address() { } } private static class BrowserInfo { @JsonProperty private String agent; @JsonProperty private String version; public BrowserInfo(String agent, String version) { this.agent = agent; this.version = version; } public BrowserInfo() { } } private static class MyModule extends Module { @Override public String getModuleName() { return "MyModule"; } @Override public Version version() { return new Version(0, 0, 1, "SNAPSHOT"); } @Override public void setupModule(Module.SetupContext context) { context.addBeanSerializerModifier(new org.codehaus.jackson.map.ser.BeanSerializerModifier() { private UnknownPartSerializer cs; @Override public JsonSerializer modifySerializer(SerializationConfig config, BasicBeanDescription beanDesc, JsonSerializer<?> serializer) { return UnknownPart.class.isAssignableFrom(beanDesc.getBeanClass()) ? new UnknownPartSerializer((BeanSerializerBase) serializer) : serializer; } }); } } private static class UnknownPartSerializer extends BeanSerializerBase { public UnknownPartSerializer(BeanSerializerBase src) { super(src); } @Override public void serialize(Object bean, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonGenerationException { UnknownPart up = (UnknownPart) bean; jgen.writeStartObject(); serializeFields(up, jgen, provider); jgen.writeEndObject(); } protected void serializeFields(UnknownPart bean, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonGenerationException { final BeanPropertyWriter[] props; if (_filteredProps != null && provider.getSerializationView() != null) { props = _filteredProps; } else { props = _props; } int i = 0; try { for (final int len = props.length; i < len; ++i) { BeanPropertyWriter prop = props[i]; if (prop != null) { // can have nulls in filtered list prop.serializeAsField(bean, jgen, provider); bean.tree.remove(prop.getName()); } } if (_anyGetterWriter != null) { _anyGetterWriter.getAndSerialize(bean, jgen, provider); } Iterator<Entry<String, JsonNode>> it = bean.tree.getFields(); while (it.hasNext()) { Entry<String, JsonNode> e = it.next(); jgen.writeFieldName(e.getKey()); jgen.writeObject(e.getValue()); } } catch (Exception e) { String name = (i == props.length) ? "[anySetter]" : props[i].getName(); wrapAndThrow(provider, e, bean, name); } catch (StackOverflowError e) { /* 04-Sep-2009, tatu: Dealing with this is tricky, since we do not * have many stack frames to spare... just one or two; can't * make many calls. */ JsonMappingException mapE = new JsonMappingException("Infinite recursion (StackOverflowError)", e); String name = (i == props.length) ? "[anySetter]" : props[i].getName(); mapE.prependPath(new JsonMappingException.Reference(bean, name)); throw mapE; } } } private static Customer customer = new Customer(1, "John Doe", new Address[]{ new Address("broadway av", "new york"), new Address("peachtree st", "atlanta") }); private static BrowserInfo browser = new BrowserInfo("IE", "6.0"); // some json found on the internet private static final String JSON_LONG = "{\"web-app\": {" + "\"servlet\": [" + "{" + "\"servlet-name\": \"cofaxCDS\"," + "\"servlet-class\": \"org.cofax.cds.CDSServlet\"," + "\"init-param\": {" + "\"configGlossary:installationAt\": \"Philadelphia, PA\"," + "\"configGlossary:adminEmail\": \"ksm@pobox.com\"," + "\"configGlossary:poweredBy\": \"Cofax\"," + "\"configGlossary:poweredByIcon\": \"/images/cofax.gif\"," + "\"configGlossary:staticPath\": \"/content/static\"," + "\"templateProcessorClass\": \"org.cofax.WysiwygTemplate\"," + "\"templateLoaderClass\": \"org.cofax.FilesTemplateLoader\"," + "\"templatePath\": \"templates\"," + "\"templateOverridePath\": \"\"," + "\"defaultListTemplate\": \"listTemplate.htm\"," + "\"defaultFileTemplate\": \"articleTemplate.htm\"," + "\"useJSP\": false," + "\"jspListTemplate\": \"listTemplate.jsp\"," + "\"jspFileTemplate\": \"articleTemplate.jsp\"," + "\"cachePackageTagsTrack\": 200," + "\"cachePackageTagsStore\": 200," + "\"cachePackageTagsRefresh\": 60," + "\"cacheTemplatesTrack\": 100," + "\"cacheTemplatesStore\": 50," + "\"cacheTemplatesRefresh\": 15," + "\"cachePagesTrack\": 200," + "\"cachePagesStore\": 100," + "\"cachePagesRefresh\": 10," + "\"cachePagesDirtyRead\": 10," + "\"searchEngineListTemplate\": \"forSearchEnginesList.htm\"," + "\"searchEngineFileTemplate\": \"forSearchEngines.htm\"," + "\"searchEngineRobotsDb\": \"WEB-INF/robots.db\"," + "\"useDataStore\": true," + "\"dataStoreClass\": \"org.cofax.SqlDataStore\"," + "\"redirectionClass\": \"org.cofax.SqlRedirection\"," + "\"dataStoreName\": \"cofax\"," + "\"dataStoreDriver\": \"com.microsoft.jdbc.sqlserver.SQLServerDriver\"," + "\"dataStoreUrl\": \"jdbc:microsoft:sqlserver://LOCALHOST:1433;DatabaseName=goon\"," + "\"dataStoreUser\": \"sa\"," + "\"dataStorePassword\": \"dataStoreTestQuery\"," + "\"dataStoreTestQuery\": \"SET NOCOUNT ON;select test='test';\"," + "\"dataStoreLogFile\": \"/usr/local/tomcat/logs/datastore.log\"," + "\"dataStoreInitConns\": 10," + "\"dataStoreMaxConns\": 100," + "\"dataStoreConnUsageLimit\": 100," + "\"dataStoreLogLevel\": \"debug\"," + "\"maxUrlLength\": 500}}," + "{" + "\"servlet-name\": \"cofaxEmail\"," + "\"servlet-class\": \"org.cofax.cds.EmailServlet\"," + "\"init-param\": {" + "\"mailHost\": \"mail1\"," + "\"mailHostOverride\": \"mail2\"}}," + "{" + "\"servlet-name\": \"cofaxAdmin\"," + "\"servlet-class\": \"org.cofax.cds.AdminServlet\"}," + "" + "{" + "\"servlet-name\": \"fileServlet\"," + "\"servlet-class\": \"org.cofax.cds.FileServlet\"}," + "{" + "\"servlet-name\": \"cofaxTools\"," + "\"servlet-class\": \"org.cofax.cms.CofaxToolsServlet\"," + "\"init-param\": {" + "\"templatePath\": \"toolstemplates/\"," + "\"log\": 1," + "\"logLocation\": \"/usr/local/tomcat/logs/CofaxTools.log\"," + "\"logMaxSize\": \"\"," + "\"dataLog\": 1," + "\"dataLogLocation\": \"/usr/local/tomcat/logs/dataLog.log\"," + "\"dataLogMaxSize\": \"\"," + "\"removePageCache\": \"/content/admin/remove?cache=pages&id=\"," + "\"removeTemplateCache\": \"/content/admin/remove?cache=templates&id=\"," + "\"fileTransferFolder\": \"/usr/local/tomcat/webapps/content/fileTransferFolder\"," + "\"lookInContext\": 1," + "\"adminGroupID\": 4," + "\"betaServer\": true}}]," + "\"servlet-mapping\": {" + "\"cofaxCDS\": \"/\"," + "\"cofaxEmail\": \"/cofaxutil/aemail/*\"," + "\"cofaxAdmin\": \"/admin/*\"," + "\"fileServlet\": \"/static/*\"," + "\"cofaxTools\": \"/tools/*\"}," + "" + "\"taglib\": {" + "\"taglib-uri\": \"cofax.tld\"," + "\"taglib-location\": \"/WEB-INF/tlds/cofax.tld\"}}}"; }