One record is expected, but the query result is multiple records

最新推荐文章于 2024-12-09 14:28:18 发布

原创最新推荐文章于 2024-12-09 14:28:18 发布 · 3.7w 阅读

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本文介绍了一个关于Mybatis-plus查询数据库时出现的错误-Onerecordisexpected,butthequeryresultismultiplerecords，并提供了相应的解决方案。该错误源于查询条件未能唯一匹配一条记录，导致返回了多条记录。

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在使用Mybatis-plus查询数据库时报错
One record is expected, but the query result is multiple records

报错内容

com.baomidou.mybatisplus.core.exceptions.MybatisPlusException: One record is expected, but the query result is multiple records

	at com.baomidou.mybatisplus.core.toolkit.ExceptionUtils.mpe(ExceptionUtils.java:49)
	at com.baomidou.mybatisplus.core.mapper.BaseMapper.selectOne(BaseMapper.java:177)
	at java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627)
	at com.baomidou.mybatisplus.core.override.MybatisMapperProxy$DefaultMethodInvoker.invoke(MybatisMapperProxy.java:162)
	at com.baomidou.mybatisplus.core.override.MybatisMapperProxy.invoke(MybatisMapperProxy.java:89)
	at com.sun.proxy.$Proxy70.selectOne(Unknown Source)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:344)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:198)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
	at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:137)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215)
	at com.sun.proxy.$Proxy71.selectOne(Unknown Source)

测试代码

@SpringBootTest
class SpringSecurity01ApplicationTests {
    @Autowired
    private UserMapper userMapper;

    @Test
    void contextLoads() {
    	//查询为tom的用户
        QueryWrapper<Users> wrapper = new QueryWrapper<>();
        wrapper.lambda().eq(Users::getUsername, "tom");
        Users users = userMapper.selectOne(wrapper);
        System.out.println(users.toString());
    }
}