Java mybatis如何使用Guava的不可变集合

发布于05月18日

我try 了创建返回类型ImmuableList并从表中 Select 一组ID，但当然，mybatis不知道如何做到这一点，并抛出异常:

org.apache.ibatis.reflection.ReflectionException: Error instantiating class com.google.common.collect.ImmutableList with invalid types () or values (). Cause: java.lang.InstantiationException
    at org.apache.ibatis.reflection.factory.DefaultObjectFactory.instantiateClass(DefaultObjectFactory.java:88)
    at org.apache.ibatis.reflection.factory.DefaultObjectFactory.create(DefaultObjectFactory.java:53)
    at org.apache.ibatis.reflection.factory.DefaultObjectFactory.create(DefaultObjectFactory.java:45)
    at org.apache.ibatis.binding.MapperMethod.convertToDeclaredCollection(MapperMethod.java:173)
    at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:154)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:80)
    at org.apache.ibatis.binding.MapperProxy$PlainMethodInvoker.invoke(MapperProxy.java:145)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:86)
    at jdk.proxy5/jdk.proxy5.$Proxy76.getAllIds(Unknown Source)
    at org.acanthite.services.UtilityService.getAllIds(UtilityService.java:98)
    at org.acanthite.services.UtilityService_ClientProxy.getAllIds(Unknown Source)
    at org.acanthite.resources.UtilityResource.ids(UtilityResource.java:77)
    at org.acanthite.resources.UtilityResource$quarkusrestinvoker$ids_8602df045ce9b7e168a75788bbd936486ed83b98.invoke(Unknown Source)
    at org.jboss.resteasy.reactive.server.handlers.InvocationHandler.handle(InvocationHandler.java:29)
    at io.quarkus.resteasy.reactive.server.runtime.QuarkusResteasyReactiveRequestContext.invokeHandler(QuarkusResteasyReactiveRequestContext.java:141)
    at org.jboss.resteasy.reactive.common.core.AbstractResteasyReactiveContext.run(AbstractResteasyReactiveContext.java:145)
    at io.quarkus.vertx.core.runtime.VertxCoreRecorder$14.runWith(VertxCoreRecorder.java:576)
    at org.jboss.threads.EnhancedQueueExecutor$Task.run(EnhancedQueueExecutor.java:2513)
    at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1538)
    at org.jboss.threads.DelegatingRunnable.run(DelegatingRunnable.java:29)
    at org.jboss.threads.ThreadLocalResettingRunnable.run(ThreadLocalResettingRunnable.java:29)
    at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
    at java.base/java.lang.Thread.run(Thread.java:833)
Caused by: java.lang.InstantiationException
    at java.base/jdk.internal.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(InstantiationExceptionConstructorAccessorImpl.java:48)
    at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:480)
    at org.apache.ibatis.reflection.factory.DefaultObjectFactory.instantiateClass(DefaultObjectFactory.java:66)
    ... 22 more

下面是我的映射器的XML:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="org.acanthite.repository.UtilityRepository">
    <select id="getAllIds" resultType="integer">
        select id from utility;
    </select>
</mapper>

映射器界面:

@Mapper
public interface UtilityRepository {
  ImmutableList<Integer> getAllIds();
}

以及我如何使用它:

@ApplicationScoped
@AllArgsConstructor
public class UtilityService {
  private final UtilityRepository repository;
  
  public ImmutableList<Integer> getAllIds() {
    return repository.getAllIds();
  }
}

有没有库或变通方法教mybatis如何实例化Guava的不可变集合(或者基本上任何其他非Java集合)？

public Object execute(SqlSession sqlSession, Object[] args) { Object result; switch (command.getType()) { // ... case SELECT: if (method.returnsVoid() && method.hasResultHandler()) { executeWithResultHandler(sqlSession, args); result = null; } else if (method.returnsMany()) { result = executeForMany(sqlSession, args); } else if (method.returnsMap()) { result = executeForMap(sqlSession, args); } else if (method.returnsCursor()) { result = executeForCursor(sqlSession, args); } else { Object param = method.convertArgsToSqlCommandParam(args); result = sqlSession.selectOne(command.getName(), param); if (method.returnsOptional() && (result == null || !method.getReturnType().equals(result.getClass()))) { result = Optional.ofNullable(result); } } break; // ... } if (result == null && method.getReturnType().isPrimitive() && !method.returnsVoid()) { throw new BindingException("Mapper method '" + command.getName() + "' attempted to return null from a method with a primitive return type (" + method.getReturnType() + ")."); } return result; }

private <E> Object executeForMany(SqlSession sqlSession, Object[] args) { List<E> result; Object param = method.convertArgsToSqlCommandParam(args); if (method.hasRowBounds()) { RowBounds rowBounds = method.extractRowBounds(args); result = sqlSession.selectList(command.getName(), param, rowBounds); } else { result = sqlSession.selectList(command.getName(), param); } // issue #510 Collections & arrays support if (!method.getReturnType().isAssignableFrom(result.getClass())) { if (method.getReturnType().isArray()) { return convertToArray(result); } return convertToDeclaredCollection(sqlSession.getConfiguration(), result); } return result; }

private <E> Object convertToDeclaredCollection(Configuration config, List<E> list) { Object collection = config.getObjectFactory().create(method.getReturnType()); MetaObject metaObject = config.newMetaObject(collection); metaObject.addAll(list); return collection; }

@Mapper public interface UtilityRepository { List<Integer> getAllIds(); } @ApplicationScoped @AllArgsConstructor public class UtilityService { private final UtilityRepository repository; public ImmutableList<Integer> getAllIds() { return ImmutableList.copyOf(repository.getAllIds()); } }

Java mybatis如何使用Guava的不可变集合

推荐答案

Java相关问答推荐

如何在Inspaut中获取当前路径的 * 模式 *？

如何让HikariCP指标在NewRelic中正确显示？

我可以从Java模块中排除maven资源文件夹吗？

具有额外列的Hibert多对多关系在添加关系时返回NonUniqueHealthExcellent

当切换javaFX场景时，stage的大小正在Minimize

OpenJDK、4K显示和文本质量

填写文本字段后锁定PDF

Spring @Value default无法计算表达式

我如何知道MediaDiscoverer何时完成发现介质？

通过Spring Security公开Spring Boot执行器端点

使SLF4J在Android中登录到Logcat，在测试中登录到控制台(Gradle依赖问题)

在Java中将int[]矩阵添加到ArrayList中，但出现错误

在实例化中指定泛型类型与不指定泛型类型之间的区别

Java集合：NPE，即使没有添加空值

用于Java的Visual Studio代码完成不起作用

我们可以在方法中声明接口吗？

Java System.getProperty在哪里检索user.home？

如何使用Rascal Evaluator从编译的JAR访问Rascal函数？

如何以事务方式向ibmmq发送消息

java 11上出现DateTimeParseException，但java 8上没有