将Json数组映射到Java模型
我有一个复杂的json,如 我试图在我的模型类“ChromeJsonModel”中对此进行映射,如:将Json数组映射到Java模型,java,json,gson,Java,Json,Gson,我有一个复杂的json,如 我试图在我的模型类“ChromeJsonModel”中对此进行映射,如: Type collectionType = new TypeToken<List<ChromeJsonModel>>(){}.getType(); List<ChromeJsonModel> jsonModelList = (List<ChromeJsonModel>) new Gson().fromJson( jsonPrettyPrintStr
Type collectionType = new TypeToken<List<ChromeJsonModel>>(){}.getType();
List<ChromeJsonModel> jsonModelList = (List<ChromeJsonModel>) new Gson().fromJson( jsonPrettyPrintString , collectionType);
有什么原因让我出错吗?我想你可以用杰克逊
ObjectMapper mapper = new ObjectMapper();
List<ChromeJsonModel> participantJsonList = mapper.readValue(jsonString, new TypeReference<List<ChromeJsonModel>>(){});
ObjectMapper mapper=new ObjectMapper();
List participantJsonList=mapper.readValue(jsonString,new TypeReference(){});
在您的json
中,根元素是json对象:
{ <---- HERE YOU HAVE "OBJECT"
"test-run": {
"duration": 508.56199999999995,
"result": "Passed",
...
}
}
您可以尝试在那里生成POJO:
您有非常复杂的
JSON
负载,其中同一属性可以有一个JSON对象
或JSON数组
<默认情况下,code>Gson不会处理这种情况,我们需要为这种一个或多个属性实现自定义反序列化程序。下面我创建了简单的POJO
模型,它表示您的JSON
负载:
class TestResponse {
@SerializedName("test-run")
private TestRun testRun;
// other properties, getters, setters, toString
}
class TestRun {
@SerializedName("test-suite")
private List<TestSuite> testSuite;
// other properties, getters, setters, toString
}
class TestSuite {
private String result;
private double duration;
@SerializedName("test-suite")
private List<TestSuite> testSuites;
@SerializedName("test-case")
private List<TestCase> testCases;
// other properties, getters, setters, toString
}
class TestCase {
private String fullname;
// other properties, getters, setters, toString
}
类
在运行时需要反序列化正确给定的JSON对象
。之后,让我们创建并定制Gson
实例:
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.annotations.SerializedName;
import com.google.gson.reflect.TypeToken;
import java.io.File;
import java.io.FileReader;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class GsonApp {
public static void main(String[] args) throws Exception {
File jsonFile = new File("./resource/test.json").getAbsoluteFile();
Type testCaseListType = new TypeToken<List<TestCase>>() {}.getType();
Type testSuiteListType = new TypeToken<List<TestSuite>>() {}.getType();
Gson gson = new GsonBuilder()
.registerTypeAdapter(testCaseListType, new OneOrManyJsonDeserializer<>(TestCase.class))
.registerTypeAdapter(testSuiteListType, new OneOrManyJsonDeserializer<>(TestSuite.class))
.setPrettyPrinting()
.create();
TestResponse response = gson.fromJson(new FileReader(jsonFile), TestResponse.class);
System.out.println(response);
}
}
我们不需要定制它。使用$Gson$Types
类,我们可以获取元素的类型并反序列化内部元素。简单用法:
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.annotations.SerializedName;
import com.google.gson.internal.$Gson$Types;
import java.io.File;
import java.io.FileReader;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class GsonApp {
public static void main(String[] args) throws Exception {
File jsonFile = new File("./resource/test.json").getAbsoluteFile();
Gson gson = new GsonBuilder()
.registerTypeAdapter(List.class, new OneOrManyJsonDeserializer())
.setPrettyPrinting()
.create();
TestResponse response = gson.fromJson(new FileReader(jsonFile), TestResponse.class);
System.out.println(response);
}
}
上述代码也适用于您。在json
中,所有东西都是一个(主要)对象,因为您有{…}
,所以使用ChromeJsonModel
而不是List
。将对象列表转换为json字符串。@MebinJoe您的意思是:ChromeJsonModel jsonModelList=new Gson()。fromJson(JSONPrettypPrintString,ChromeJsonModel.class);我尝试了这个,但出现了同样的错误。这对我来说很有效。尽管每次遇到这种情况时使用自定义反序列化程序都很痛苦。这是试图解决问题的唯一答案。@Einstein_AB,我很高兴听到它对你有效。我发现了一个更容易接受的解决方案。我们只需要一个反序列化程序就可以了这一次。
class TestResponse {
@SerializedName("test-run")
private TestRun testRun;
// other properties, getters, setters, toString
}
class TestRun {
@SerializedName("test-suite")
private List<TestSuite> testSuite;
// other properties, getters, setters, toString
}
class TestSuite {
private String result;
private double duration;
@SerializedName("test-suite")
private List<TestSuite> testSuites;
@SerializedName("test-case")
private List<TestCase> testCases;
// other properties, getters, setters, toString
}
class TestCase {
private String fullname;
// other properties, getters, setters, toString
}
class OneOrManyJsonDeserializer<E> implements JsonDeserializer<List<E>> {
private final Class<E> clazz;
public OneOrManyJsonDeserializer(Class<E> clazz) {
this.clazz = clazz;
}
@Override
public List<E> deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
if (json instanceof JsonArray) {
final JsonArray array = (JsonArray) json;
final int size = array.size();
if (size == 0) {
return Collections.emptyList();
}
final List<E> suites = new ArrayList<>(size);
for (int i = 0; i < size; i++) {
suites.add(context.deserialize(array.get(i), clazz));
}
return suites;
}
E suite = context.deserialize(json, clazz);
return Collections.singletonList(suite);
}
}
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.annotations.SerializedName;
import com.google.gson.reflect.TypeToken;
import java.io.File;
import java.io.FileReader;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class GsonApp {
public static void main(String[] args) throws Exception {
File jsonFile = new File("./resource/test.json").getAbsoluteFile();
Type testCaseListType = new TypeToken<List<TestCase>>() {}.getType();
Type testSuiteListType = new TypeToken<List<TestSuite>>() {}.getType();
Gson gson = new GsonBuilder()
.registerTypeAdapter(testCaseListType, new OneOrManyJsonDeserializer<>(TestCase.class))
.registerTypeAdapter(testSuiteListType, new OneOrManyJsonDeserializer<>(TestSuite.class))
.setPrettyPrinting()
.create();
TestResponse response = gson.fromJson(new FileReader(jsonFile), TestResponse.class);
System.out.println(response);
}
}
class OneOrManyJsonDeserializer implements JsonDeserializer<List<?>> {
@Override
public List<?> deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
final Type elementType = $Gson$Types.getCollectionElementType(typeOfT, List.class);
if (json instanceof JsonArray) {
final JsonArray array = (JsonArray) json;
final int size = array.size();
if (size == 0) {
return Collections.emptyList();
}
final List<?> suites = new ArrayList<>(size);
for (int i = 0; i < size; i++) {
suites.add(context.deserialize(array.get(i), elementType));
}
return suites;
}
Object suite = context.deserialize(json, elementType);
return Collections.singletonList(suite);
}
}
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.annotations.SerializedName;
import com.google.gson.internal.$Gson$Types;
import java.io.File;
import java.io.FileReader;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class GsonApp {
public static void main(String[] args) throws Exception {
File jsonFile = new File("./resource/test.json").getAbsoluteFile();
Gson gson = new GsonBuilder()
.registerTypeAdapter(List.class, new OneOrManyJsonDeserializer())
.setPrettyPrinting()
.create();
TestResponse response = gson.fromJson(new FileReader(jsonFile), TestResponse.class);
System.out.println(response);
}
}