Java Spring DataCouchbase自定义存储库方法

大家好，我在SpringDataCouchbase上使用couchbase模板添加一个简单的自定义查询时遇到了问题

存储库接口：

@RepositoryRestResource
public interface EmployeeRepository extends CouchbasePagingAndSortingRepository<Employee, String>, EmployeeCustomRepository {
}

public interface EmployeeCustomRepository {
    List<Employee> customMethod(String firstName, String lastName);
}

主要应用

@SpringBootApplication
public class SpringDataCouchbaseCustomExampleApplication implements CommandLineRunner {

    public static void main(String[] args) {
        SpringApplication.run(SpringDataCouchbaseCustomExampleApplication.class, args);
    }

    @Autowired
    private EmployeeRepository repository;

    @Override
    public void run(String... strings) throws Exception {
        String empId = "1";

        Employee employee = repository.findOne(empId);

        if(employee == null) {
            employee = new Employee(empId, "Joe", "Smith");
            repository.save(employee);
        }

        List<Employee> result = repository.customMethod("Joe", "Smith");

        System.out.println("correct result:" + result.size());


        result = repository.customMethod("Joe", "Wopa");
        System.out.println("no result:" + result.size());
    }
}

---

这是由于您编写查询语句的方式和在模板上使用的方法的混合造成的

首先，您正在尝试检索

Employee

s，它们是成熟的实体。此

findByN1QLProjection

用于一种不同类型的查询，您只需选择几个字段，例如

count（*）

查询

因此，您应该使用

findByN1ql

。无论如何，这都有一个问题：N1QL返回的最简单（但也是最自然）查询格式不适合Jackson的反序列化

首先，N1QL将每个结果包装在一个JSON对象中，其中有一个以数据来源的bucket命名的字段，这里是“default”）。这就是您看到的问题：(

其次，为了反序列化实体，spring data couchbase需要您的N1QL查询来选择

select（*）

没有涵盖的两个特定内容：元数据（即

ID

和

CAS

）

我们提供了

N1qlUtils

类来帮助您解决这个问题。。。 请注意，处理编写自定义方法的是如何在步骤8中使用

N1qlUtils

类来构建查询的

我同意这有点误导，因为它使用了投影方法，所以您必须对其进行一些调整，以使用

N1qlUtils.createSelectFromForEntity

和

N1qlUtils.createWhere FilterForEntity

。类似这样的内容：

// your own WHERE criteria:
Expression where = x("firstName = $1 and lastName = $2");

Statement statement =
    //this will produce the adequate SELECT..FROM.. clause:
    N1qlUtils.createSelectFromForEntity(template.getCouchbaseBucket().name())
    //use the DSL to continue to the WHERE clause
    .where(
        //this will produce the adequate WHERE criterias in addition to your own:
        //(see doc snippet for getting converter and entityInfo)
        N1qlUtils.createWhereFilterForEntity(where, converter, entityInfo));

然后，您可以使用该语句（而不是字符串）创建一个

N1qlQuery

，并使用

findByN1ql

执行它

快速备选方案：

您可以使用基于字符串的查询派生

---

请看一个例子。您可以在

EmployeeRepository

界面的注释中添加一个类似的签名，并对WHERE子句进行一些调整（无需在此处进行自定义实现）.

Simon谢谢你的回答！现在开始工作了。我认为在参考文档中有一个显示非计数查询的部分可能会有所帮助。对于新用户，我没有发现这些文档过于直观。再次感谢你的帮助！好的建议，已发布。请毫不犹豫地在PR中为文档起草一个附加内容（一个维护人员可以在以后对它进行迭代）：）太棒了，谢谢Simon。我会看看我是否能在周末做到这一点。

@SpringBootApplication
public class SpringDataCouchbaseCustomExampleApplication implements CommandLineRunner {

    public static void main(String[] args) {
        SpringApplication.run(SpringDataCouchbaseCustomExampleApplication.class, args);
    }

    @Autowired
    private EmployeeRepository repository;

    @Override
    public void run(String... strings) throws Exception {
        String empId = "1";

        Employee employee = repository.findOne(empId);

        if(employee == null) {
            employee = new Employee(empId, "Joe", "Smith");
            repository.save(employee);
        }

        List<Employee> result = repository.customMethod("Joe", "Smith");

        System.out.println("correct result:" + result.size());


        result = repository.customMethod("Joe", "Wopa");
        System.out.println("no result:" + result.size());
    }
}

java.lang.IllegalStateException: Failed to execute CommandLineRunner
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:803) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:784) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.afterRefresh(SpringApplication.java:771) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1186) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1175) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    at com.example.SpringDataCouchbaseCustomExampleApplication.main(SpringDataCouchbaseCustomExampleApplication.java:14) [classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_77]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_77]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_77]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_77]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-1.4.3.RELEASE.jar:1.4.3.RELEASE]
Caused by: java.lang.RuntimeException: Cannot decode ad-hoc JSON
    at org.springframework.data.couchbase.core.convert.translation.JacksonTranslationService.decodeFragment(JacksonTranslationService.java:245) ~[spring-data-couchbase-2.1.6.RELEASE.jar:na]
    at org.springframework.data.couchbase.core.CouchbaseTemplate.findByN1QLProjection(CouchbaseTemplate.java:466) ~[spring-data-couchbase-2.1.6.RELEASE.jar:na]
    at com.example.EmployeeRepositoryImpl.customMethod(EmployeeRepositoryImpl.java:26) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_77]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_77]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_77]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_77]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:503) ~[spring-data-commons-1.12.6.RELEASE.jar:na]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:478) ~[spring-data-commons-1.12.6.RELEASE.jar:na]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:460) ~[spring-data-commons-1.12.6.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:61) ~[spring-data-commons-1.12.6.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.data.couchbase.repository.support.ViewPostProcessor$ViewInterceptor.invoke(ViewPostProcessor.java:87) ~[spring-data-couchbase-2.1.6.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213) ~[spring-aop-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at com.sun.proxy.$Proxy77.customMethod(Unknown Source) ~[na:na]
    at com.example.SpringDataCouchbaseCustomExampleApplication.run(SpringDataCouchbaseCustomExampleApplication.java:31) [classes/:na]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:800) [spring-boot-1.4.3.RELEASE.jar:1.4.3.RELEASE]
    ... 11 common frames omitted
Caused by: com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "default" (class com.example.Employee), not marked as ignorable (3 known properties: "lastName", "id", "firstName"])
 at [Source: {"default":{"firstName":"Joe","lastName":"Smith","_class":"com.example.Employee"}}; line: 1, column: 83] (through reference chain: com.example.Employee["default"])
    at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:62) ~[jackson-databind-2.8.5.jar:2.8.5]
    at com.fasterxml.jackson.databind.DeserializationContext.handleUnknownProperty(DeserializationContext.java:834) ~[jackson-databind-2.8.5.jar:2.8.5]
    at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:1093) ~[jackson-databind-2.8.5.jar:2.8.5]
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1477) ~[jackson-databind-2.8.5.jar:2.8.5]
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperties(BeanDeserializerBase.java:1431) ~[jackson-databind-2.8.5.jar:2.8.5]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer._deserializeUsingPropertyBased(BeanDeserializer.java:487) ~[jackson-databind-2.8.5.jar:2.8.5]
    at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1198) ~[jackson-databind-2.8.5.jar:2.8.5]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:314) ~[jackson-databind-2.8.5.jar:2.8.5]
    at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:148) ~[jackson-databind-2.8.5.jar:2.8.5]
    at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3798) ~[jackson-databind-2.8.5.jar:2.8.5]
    at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2842) ~[jackson-databind-2.8.5.jar:2.8.5]
    at org.springframework.data.couchbase.core.convert.translation.JacksonTranslationService.decodeFragment(JacksonTranslationService.java:242) ~[spring-data-couchbase-2.1.6.RELEASE.jar:na]
    ... 33 common frames omitted

// your own WHERE criteria:
Expression where = x("firstName = $1 and lastName = $2");

Statement statement =
    //this will produce the adequate SELECT..FROM.. clause:
    N1qlUtils.createSelectFromForEntity(template.getCouchbaseBucket().name())
    //use the DSL to continue to the WHERE clause
    .where(
        //this will produce the adequate WHERE criterias in addition to your own:
        //(see doc snippet for getting converter and entityInfo)
        N1qlUtils.createWhereFilterForEntity(where, converter, entityInfo));