mybatis+MySQL简单实例及错误解决

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数据库和数据表

项目目录（动态 web项目）

1、首先是与user表对应的实体类User.java

package com.entity;public class User {private int id;private String name;private String password;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}

2、添加配置文件mapperUser.xml 完成实体类到数据表的映射，并编写sql语句

<?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="com.mapper.UserMapper"><resultMap type="com.entity.User" id="mapUser">  <id property="id" column="id" />  <result property="name" column="name" />  <result property="password" column="password" /></resultMap><select id="selectById" parameterType="int"  resultMap="mapUser">  select  *    from  user  where id=#{id}</select></mapper>

3、添加配置文件configuration.xml 完成数据源的配置，并指向mapperUser.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration>  <environments default="development">    <environment id="development">      <transactionManager type="JDBC" />        <dataSource type="POOLED">           <property name="driver" value="com.mysql.jdbc.Driver" />           <property name="url" value="jdbc:mysql://localhost:3306/user_information?useSSL=false" />           <property name="username" value="admin" />           <property name="password" value="123456" />                  </dataSource>    </environment>  </environments>    <mappers>    <mapper resource="com/mapper/UserMapper.xml"></mapper>  </mappers> </configuration>

4、编写测试代码Test.java 小小应用下了封装，mySqlSessionFactory.java 可以不用，直接在Test.java 中直接写

package com.test;import java.io.IOException;import java.io.Reader;import org.apache.ibatis.io.Resources;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;public class MysqlSessionFactory {static SqlSession session;public SqlSession getSqlSession(){try {Reader reader = Resources.getResourceAsReader("configuration.xml");SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);session = sqlSessionFactory.openSession();} catch (IOException e) {e.printStackTrace();}return session;}}

package com.test;import org.apache.ibatis.session.SqlSession;import com.entity.User;public class Test {public static void main(String[] args) {MysqlSessionFactory mysqlSessionFactory = new MysqlSessionFactory();SqlSession session = mysqlSessionFactory.getSqlSession();System.out.println(session);User user = session.selectOne("com.mapper.UserMapper.selectById", 1);System.out.println("对应的姓名是" + user.getName());session.commit();}}

运行结果

以上便是整个简单的mybatis+MySQL实例

错误和解决方法

错误：正常运行，但弹出警告，如图

解决方法：该句后面加上，如图所示

相关包下载地址：http://download.csdn.net/detail/forrest_ou/9629182

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