mybatis实现简单的增删改查

项目结构添加maven依赖配置mybatis-config.xml创建UserMapper.xml 创建dao层并写UserMapper创建实体类Domain层并写User在主程序中测试增删改查创建db数据库,建立user表运行结果

项目结构

添加maven依赖

创建好springboot项目后在pom.xml中添加

// An highlighted block <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.4.5</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.43</version> </dependency>

配置mybatis-config.xml

下面展示一些 内联代码片。

// An highlighted block <?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> <settings> <setting name="mapUnderscoreToCamelCase" value="true"/> </settings> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/><!--配置数据库驱动--> <property name="url" value="jdbc:mysql://127.0.0.1:3306/db?useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=false"/> <property name="username" value="root"/> <property name="password" value="admin"/> </dataSource> </environment> </environments> <mappers> <mapper resource="mapper/UserMapper.xml"/><!--注意--> </mappers> </configuration>

创建UserMapper.xml

// An highlighted block <?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="Dao.UserMapper"> <select id="selectUser" resultType="Domain.User"> select * from user </select> <select id="searchId" resultType="Domain.User"> select * from user where id=#{User_id} </select> <insert id="add" parameterType="Domain.User" useGeneratedKeys="true" keyProperty="id" keyColumn="id"> INSERT INTO `user` ( `Id`, `pwd`, `name`) VALUES (#{id},#{pwd},#{name}); </insert> <update id="update" parameterType="Domain.User"> update user set pwd=#{pwd}, name=#{name} where Id=#{id} </update> <delete id="delete" parameterType="Domain.User"> delete from user where Id=#{id} </delete> </mapper>

创建dao层并写UserMapper

// An highlighted block package Dao; import Domain.User; import java.util.List; public interface UserMapper { //查询所有用户 List<User> selectUser(); //按id查询 User searchId(int id); //添加用户 void add(User user); //更改信息 void update(User user); //删除用户 void delete(User user); }

创建实体类Domain层并写User

// An highlighted block package Domain; public class User { private int id; private String pwd; private String name; public User(){} public User(int id,String pwd,String name){ this.id=id; this.pwd= pwd; this.name = name; } 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 getPwd() { return pwd; } public void setPwd(String pwd) { this.pwd = pwd; } @Override public String toString() { return "User{" + "id=" + id + ", name='" + name + '\'' + ", pwd='" + pwd + '\'' + '}'; } }

在主程序中测试增删改查

// An highlighted block package com.zhang.firstproject; import Dao.UserMapper; import Domain.User; 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 org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import java.io.IOException; import java.io.InputStream; import java.util.List; @SpringBootApplication public class FirstprojectApplication { public FirstprojectApplication() throws IOException { } public static void main(String[] args) { SpringApplication.run(FirstprojectApplication.class, args); } String resouce = "config/mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(resouce); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); SqlSession sqlSession = sqlSessionFactory.openSession(); { UserMapper usermapper = sqlSession.getMapper(Dao.UserMapper.class); User user = new User(); user.setPwd("1234"); user.setName("张五"); usermapper.add(user); sqlSession.commit();//防止插入运行成功,但没有插入数据库中 List<User> alluser = usermapper.selectUser(); System.out.println(alluser.toString()); } }

创建db数据库,建立user表

运行结果