如何使用 Spring Data JDBC 选择引用的实体

【问题标题】：How to select referenced entities with Spring Data JDBC如何使用 Spring Data JDBC 选择引用的实体
【发布时间】：2019-01-29 08:44:10
【问题描述】：

如何使用 Spring Data JDBC 选择 One-To-May 关系中的引用实体？

当我在this blog上尝试以下代码时

class PurchaseOrder {

    @Id
    private Long id;
    private String shippingAddress;
    private Set<OrderItem> items;
}

class OrderItem {

    @Id
    private Long id;
    private int quantity;
    private String product;
}

@Test
void test() {
    PurchaseOrder purchaseOrder = PurchaseOrder.of("Tokyo");
    purchaseOrder.addItem(4, "Captain Future Comet Lego set");
    purchaseOrder.addItem(2, "Cute blue angler fish plush toy");
    orderRepository.save(purchaseOrder);

    Iterable<PurchaseOrder> result = orderRepository.findAll(); //throw MappingException !!
    result.forEach(System.out::println);
}

这会在下面引发异常：

org.springframework.data.mapping.MappingException: Could not read property @org.springframework.data.annotation.Id()private final java.lang.Long com.example.demo.OrderItem.id from result set!

    at org.springframework.data.jdbc.core.EntityRowMapper.readFrom(EntityRowMapper.java:130)
    at org.springframework.data.jdbc.core.EntityRowMapper.readEntityFrom(EntityRowMapper.java:143)
    at org.springframework.data.jdbc.core.EntityRowMapper.readFrom(EntityRowMapper.java:124)
    at org.springframework.data.jdbc.core.EntityRowMapper.lambda$createInstance$0(EntityRowMapper.java:167)
......
Caused by: org.h2.jdbc.JdbcSQLException: Column "items_id" not found [42122-197]
    at org.h2.message.DbException.getJdbcSQLException(DbException.java:357)
    at org.h2.message.DbException.get(DbException.java:179)
    at org.h2.message.DbException.get(DbException.java:155)
......

看起来spring data jdbc在从ResultSet检索值时将父实体的名称作为前缀添加到子实体的列中。但是我不能在文档上使用这个映射规则...

有没有办法自定义这个映射规则？

DDL：

create table purchase_order (
  id bigint primary key auto_increment,
  shipping_address varchar NOT NULL
);

create table order_item (
  id bigint primary key auto_increment,
  purchase_order bigint NOT NULL,
  quantity int NOT NULL,
  product varchar NOT NULL
);

[更新]

spring-data-jdbc的版本是1.0.4.RELEASE。

SQL 语句在这里：

2019-01-29 23:49:16.932 DEBUG 80409 --- [           main] o.s.jdbc.core.JdbcTemplate               : Executing prepared SQL statement [SELECT purchase_order.id AS id, purchase_order.shipping_address AS shipping_address FROM purchase_order]

完整的堆栈跟踪是

org.springframework.data.mapping.MappingException: Could not read property @org.springframework.data.annotation.Id()private java.lang.Long com.example.demo.OrderItem.id from result set!

    at org.springframework.data.jdbc.core.EntityRowMapper.readFrom(EntityRowMapper.java:130)
    at org.springframework.data.jdbc.core.EntityRowMapper.readEntityFrom(EntityRowMapper.java:143)
    at org.springframework.data.jdbc.core.EntityRowMapper.readFrom(EntityRowMapper.java:124)
    at org.springframework.data.jdbc.core.EntityRowMapper.lambda$createInstance$0(EntityRowMapper.java:167)
    at org.springframework.data.relational.core.conversion.BasicRelationalConverter$ConvertingParameterValueProvider.getParameterValue(BasicRelationalConverter.java:251)
    at org.springframework.data.convert.ReflectionEntityInstantiator.createInstance(ReflectionEntityInstantiator.java:75)
    at org.springframework.data.convert.ClassGeneratingEntityInstantiator.createInstance(ClassGeneratingEntityInstantiator.java:84)
    at org.springframework.data.relational.core.conversion.BasicRelationalConverter.createInstance(BasicRelationalConverter.java:141)
    at org.springframework.data.jdbc.core.EntityRowMapper.createInstance(EntityRowMapper.java:160)
    at org.springframework.data.jdbc.core.EntityRowMapper.mapRow(EntityRowMapper.java:71)
    at org.springframework.jdbc.core.RowMapperResultSetExtractor.extractData(RowMapperResultSetExtractor.java:94)
    at org.springframework.jdbc.core.RowMapperResultSetExtractor.extractData(RowMapperResultSetExtractor.java:61)
    at org.springframework.jdbc.core.JdbcTemplate$1.doInPreparedStatement(JdbcTemplate.java:679)
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:617)
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:669)
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:694)
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:748)
    at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.query(NamedParameterJdbcTemplate.java:215)
    at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.query(NamedParameterJdbcTemplate.java:227)
    at org.springframework.data.jdbc.core.DefaultDataAccessStrategy.findAll(DefaultDataAccessStrategy.java:217)
    at org.springframework.data.jdbc.core.JdbcAggregateTemplate.findAll(JdbcAggregateTemplate.java:158)
    at org.springframework.data.jdbc.repository.support.SimpleJdbcRepository.findAll(SimpleJdbcRepository.java:84)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:359)
    at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:200)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:644)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:608)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.lambda$invoke$3(RepositoryFactorySupport.java:595)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:595)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:93)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)
    at com.sun.proxy.$Proxy68.findAll(Unknown Source)
    at com.example.demo.OrderRepositoryTest.test(OrderRepositoryTest.java:61)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:532)
    at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:115)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:171)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:167)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:114)
    at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:59)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$4(NodeTestTask.java:108)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:98)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:74)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$4(NodeTestTask.java:112)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:98)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:74)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1540)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$4(NodeTestTask.java:112)
    at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:72)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:98)
    at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:74)
    at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
    at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:220)
    at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$6(DefaultLauncher.java:188)
    at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:202)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:181)
    at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:128)
    at com.intellij.junit5.JUnit5IdeaTestRunner.startRunnerWithArgs(JUnit5IdeaTestRunner.java:74)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: org.h2.jdbc.JdbcSQLException: Column "items_id" not found [42122-197]
    at org.h2.message.DbException.getJdbcSQLException(DbException.java:357)
    at org.h2.message.DbException.get(DbException.java:179)
    at org.h2.message.DbException.get(DbException.java:155)
    at org.h2.jdbc.JdbcResultSet.getColumnIndex(JdbcResultSet.java:3174)
    at org.h2.jdbc.JdbcResultSet.get(JdbcResultSet.java:3247)
    at org.h2.jdbc.JdbcResultSet.getObject(JdbcResultSet.java:529)
    at org.springframework.data.jdbc.core.EntityRowMapper.readFrom(EntityRowMapper.java:127)
    ... 86 more

【问题讨论】：

  • 可以分享一下这两张表的数据库结构吗
  • @LalitMehra 哎呀，更新了。
  • 首先，您的表没有 items_id 列，因此似乎触发了异常。其次，您的代码不反映任何映射信息。
  • 能否请您发布完整的堆栈跟踪、您正在使用的版本以及您能否通过将org.springframework.jdbc.core 的日志级别设置为trace 来激活SQL 语句的日志记录？如果你可以在 Github 上发布你的项目，那事情可能会变得相当容易。
  • @LalitMehra 我试过但发现了类似的异常：org.h2.jdbc.JdbcSQLException: Column "items_items_id" not found

标签： java spring spring-data-jdbc


【解决方案1】：

以下复制自官方文档。

总结一下：Spring Data JDBC 不支持多对一或多对多关系。为了对这些进行建模，请使用 ID。这鼓励了域模型的干净模块化。它还消除了人们必须解决并学习推理这种映射是否可能的一整类问题。

 class PurchaseOrder {

   @Id
   private Long id;
   private String shippingAddress;
  private Set<OrderItem> items;

     private OrderItemRef createOrderItem(OrderItem orderItem ) {

   OrderItemRef orderItemRef = new OrderItemRef ();
   orderItemRef.orderItem = orderItemRef.id;
   return orderItemRef ;
 }
 }

  @Table("Purchase_OrderItem ")
class OrderItemRef {
    Long orderItem;
 }


 class OrderItem {

   @Id
  private Long id;
  private int quantity;
  private String product;
 }

【讨论】：

  • Spring Data JDBC 能否从实体类生成 DDL？我知道 Spring Data JPA（或 Hibernate）可以做到。
  • 请检查我修改后的答案。我已经转发了这个spring.io/blog/2018/09/24/…
  • @RyoShindo 目前不支持 Spring Data JDBC 不支持模式生成。
  • @SupunDharmarathne 但 OP 海报试图做的似乎不是多对 X 关系。他们只是缺少一列。
  • 您似乎遇到了jira.spring.io/browse/DATAJDBC-127 的变体，您的实体看起来与您发布的内容有很大不同。特别是它确实期望在构造函数中有一个Set。你能从构造函数中删除Set吗？
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