Idea（Mybatis框架）中对SQL的增删改查

中对SQL的增删改查"/>

Idea（Mybatis框架）中对SQL的增删改查

 一：创建原始数据库

二：创建mybatis_1文件，搭建原始Mybatis框架

        1：引入相关依赖

        2：引入相关资源（config核心配置文件、db、log4j）

        3：\src\main\java分别创建包（实体包、映射包、测试包）并创建相应的class类文件

        4：创建实体包与映射链接接口

        5：创建测试类（find查）

三：在Idea中写Mysql的增删改查

 一：创建原始数据库

        

 二：创建mybatis_1文件，搭建原始Mybatis框架

        

        1：引入相关依赖

            

        代码如下：xml

<dependencies><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.32</version></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version><scope>test</scope></dependency><dependency><groupId>org.example</groupId><artifactId>mybatis_1</artifactId><version>1.0-SNAPSHOT</version></dependency><dependency><groupId>log4j</groupId><artifactId>log4j</artifactId><version>1.2.12</version></dependency>
</dependencies>

        2：引入相关资源（config核心配置文件、db、log4j）

        

        代码如下：

                mybatis-config:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configurationPUBLIC "-//mybatis//DTD Config 3.0//EN"".dtd">
<configuration><!-- 环境配置 --><!-- 加载类路径下的属性文件 --><properties resource="db.properties"/><environments default="development"><environment id="development"><transactionManager type="JDBC"/><!-- 数据库连接相关配置 ,db.properties文件中的内容--><dataSource type="POOLED"><property name="driver" value="${mysql.driver}"/><property name="url" value="${mysql.url}"/><property name="username" value="${mysql.username}"/><property name="password" value="${mysql.password}"/></dataSource></environment></environments><!-- mapping文件路径配置 --><mappers><mapper resource="mapper/UserMapper.xml"/></mappers></configuration>

                log4j代码：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="/"><appender name="STDOUT" class="org.apache.log4j.ConsoleAppender"><param name="Encoding" value="UTF-8"/><layout class="org.apache.log4j.PatternLayout"><param name="ConversionPattern" value="%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L) \n"/></layout></appender><logger name="java.sql"><level value="debug"/></logger><logger name="org.apache.ibatis"><level value="info"/></logger><root><level value="debug"/><appender-ref ref="STDOUT"/></root>
</log4j:configuration>

                db代码：mybatis1是你创建数据库的名

mysql.driver=com.mysql.cj.jdbc.Driver
mysql.url=jdbc:mysql://localhost:3306/mybatis1?serverTimezone=UTC&characterEncoding=utf8&useUnicode=true&useSSL=false
mysql.username=root
mysql.password=123456

        3：\src\main\java分别创建包（实体包、映射包、测试包）并创建相应的class类文件

                ①.pojo的class代码：

package org.example.pojo;public class Users {private int id;private String name;private int age;private String sex;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 int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}@Overridepublic String toString() {return "Users{" +"id=" + id +", name='" + name + '\'' +", age=" + age +", sex='" + sex + '\'' +'}';}
}

                 ②、Mapper和Utils的代码暂时不填

        4：创建实体包与映射链接接口

                UsersMapper代码如下：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapperPUBLIC "-//mybatis//DTD mapper 3.0//EN"".dtd">
<!-- mapper为映射的根节点-->
<!-- mapper为映射的根节点，namespace指定Dao接口的完整类名
mybatis会依据这个接口动态创建一个实现类去实现这个接口，
而这个实现类是一个Mapper对象-->
<mapper namespace="com.example.pojo.User"><!--id ="接口中的方法名"parameterType="传入的参数类型"resultType = "返回实体类对象，使用包.类名"--><select id="findById" parameterType="int"resultType="com.example.pojo.User">select *from userswhere id = #{id}</select>
</mapper>

        5：创建测试类

代码如下：

@Test
public void testFindUserById(){SqlSession session = MyBatisUtil.getSqlSession();UserMapper mapper = session.getMapper(UserMapper.class);User user = mapper.findUserById(1);System.out.println("user = " + user);}

三：在Idea中写Mysql的增删改查

        ①：写映射类：

                ②：写映射文件：

<insert id="insertEmp" parameterType="Employee">insert into employee values(null, #{name}, #{age}, #{position});
</insert><!--public int updateEmpById(Employee employee);-->
<update id="updateEmpById" parameterType="employee">update employee set name=#{name}, age=#{age}, position = #{position} where id = #{id}
</update><!--public int deleteEmpById(int id);-->
<delete id="deleteEmpById" parameterType="int">delete from employee where id=#{id}
</delete>

 

                ③：写测试类：

public class TestUser {@Testpublic void testFindUserById(){SqlSession session = MyBatisUtil.getSqlSession();UserMapper mapper = session.getMapper(UserMapper.class);User user = mapper.findUserById(1);System.out.println("user = " + user);}@Testpublic void testInsertEmp(){SqlSession session = MyBatisUtil.getSqlSession();UserMapper mapper = session.getMapper(UserMapper.class);User emp = new User();emp.setUname("小米");emp.setUage(24);emp.setUid(3);int result = mapper.insertUser(emp);}@Testpublic void testUpdateEmp(){SqlSession session = MyBatisUtil.getSqlSession();UserMapper mapper = session.getMapper(UserMapper.class);User emp = new User();emp.setUid(4);emp.setUname("小明");emp.setUage(36);int result = mapper.updateUserById(emp);}@Testpublic void testDeleteEmpById(){SqlSession session = MyBatisUtil.getSqlSession();UserMapper mapper = session.getMapper(UserMapper.class);int result = mapper.delUserById(5);}}

执行结果：