mybatis中出现了问题不知道咋改了

使用mybatis时遇到的问题
错误提示如下

Exception in thread "main" org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: org.apache.ibatis.executor.ExecutorException: No constructor found in pojo.User matching [java.lang.Integer, java.lang.String, java.lang.String]
### The error may exist in UserMapper.xml
### The error may involve mapper.UserMapper.SelectUser
### The error occurred while handling results
### SQL: select * from tb_user where username=? and password=?;
### Cause: org.apache.ibatis.executor.ExecutorException: No constructor found in pojo.User matching [java.lang.Integer, java.lang.String, java.lang.String]
    at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:150)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:77)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:83)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59)
    at com.sun.proxy.$Proxy2.SelectUser(Unknown Source)
    at simpletest.main(simpletest.java:25)
Caused by: org.apache.ibatis.executor.ExecutorException: No constructor found in pojo.User matching [java.lang.Integer, java.lang.String, java.lang.String]
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createByConstructorSignature(DefaultResultSetHandler.java:668)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createResultObject(DefaultResultSetHandler.java:621)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.createResultObject(DefaultResultSetHandler.java:594)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.getRowValue(DefaultResultSetHandler.java:396)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValuesForSimpleResultMap(DefaultResultSetHandler.java:355)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleRowValues(DefaultResultSetHandler.java:330)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSet(DefaultResultSetHandler.java:303)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSets(DefaultResultSetHandler.java:196)
    at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:64)
    at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:79)
    at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:63)
    at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:326)
    at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148)
    ... 6 more

按照这个提示检查了UsserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="mapper.UserMapper">
    <select id="SelectUser" resultType="pojo.User">
select *
from tb_user
where username=#{username}
and password=#{password};





    </select>





</mapper>

也没发现问题

以下是main方法

import mapper.UserMapper;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import pojo.User;

import java.io.IOException;
import java.io.InputStream;

public class simpletest {
    public static void main(String[] args) throws IOException {

        User user=new User("zhangsan","123");

        //mybatis
        SqlSessionFactory sqlSessionFactory;
        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);


        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

        User user1 = userMapper.SelectUser(user);

        if (user1 !=null){
            System.out.println("有这个人");
        }else
            System.out.println("没有这个人");


    }
}

几个小时前是·能运行的但是idea提示啥之后给转换啥了就不行了麻烦大家看看

回答：它提示你没有这个构造函数，你想把结果直接转化为实体类，需要构造函数；

不过我自己采用mybatis-plus尝试了几下，不管有没有构造函数，它都没有问题，要是你加了构造函数还是有错误的话，你把你的配置文件mybatis-config.xml发一下，我这边测试一下看看

【相关推荐】

这篇博客: mybatis中核心配置文件和映射文件的一些知识点中的 对mybatis中映射文件的概述（一般命名为xxxMapper.xml) 部分也许能够解决你的问题, 你可以仔细阅读以下内容或跳转源博客中阅读:

如果你已经解决了该问题, 非常希望你能够分享一下解决方案, 写成博客, 将相关链接放在评论区, 以帮助更多的人 ^-^

mybatis中出现了问题 不知道咋改了

mybatis中出现了问题不知道咋改了