mybatis实现查找列表以及增删改差

傷城~ 2022-05-20 08:45 149阅读 0赞

#### 1、首先创建User类与表中结构相对应 ####

![70][]

User.class,写好getter和setter方法。

package com.xiao.mybatis.bean;
    
    public class User {
        private int id;
        private String name;
        int age;
        String sex;
        String school;
    
        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;
        }
    
        public String getSchool() {
            return school;
        }
    
        public void setSchool(String school) {
            this.school = school;
        }
    }

#### 2、写IUser接口映射文件，里面有增删改差和获取用户列表的方法。    ####

package com.xiao.mybatis.dao;
    
    import com.xiao.mybatis.bean.User;
    
    import java.util.List;
    
    public interface IUser {
        public List<User> getUserList();
            public void insertUser(User user);
            public void updateUser(User user);
            public void deleteUser(int id);
            public User getUser(int id);
    
    
    }

#### 3、写mapper映射文件User.xml ####

其中，有对应IUser接口中，每一个方法的sql语句类型，语句具体值，参数类型和返回值类型。namespace一定要是IUser所在的位置。

<?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.xiao.mybatis.dao.IUser">
        <select id="getUser" parameterType="int" resultType="com.xiao.mybatis.bean.User">
            SELECT *
            FROM USER
            WHERE id = #{id}
        </select>
    
        <insert id="insertUser" parameterType="User">
            INSERT INTO USER (id,name,age,sex,school)
            VALUES (#{id},#{name},#{age},#{sex},#{school})
        </insert>
    
        <select id="getUserList" resultType="com.xiao.mybatis.bean.User">
            select * FROM  USER
        </select>
    
        <update id="updateUser" parameterType="User">
            UPDATE USER
            SET
            name=#{name},
            age = #{age},
            sex = #{sex},
            school = #{school}
            WHERE
            id =
            #{id}
        </update>
    
    
        <delete id="deleteUser" parameterType="int">
            DELETE FROM USER WHERE id = #{id}
        </delete>
    
    </mapper>

#### 4、编写主类进行测试。 ####

package com.xiao.mybatis.bean;
    /*
    *
    * 实现增删改查
    * */
    
    import com.xiao.mybatis.dao.IUser;
    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 java.io.Reader;
    import java.text.MessageFormat;
    import java.util.List;
    
    public class DemoTest {
    
        private static SqlSessionFactory sqlSessionFactory;
    
        static {
            try{
                Reader reader = Resources.getResourceAsReader("mybatis-remote-config.xml");
                sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    
        public static void main(String[] args) {
            SqlSession session = sqlSessionFactory.openSession();
            try{
    
                // 用户数据列表
                //getUserList();
                //插入数据
                 //testInsert();
    
                // 更新用户
                testUpdate();
    
                // 删除数据
                //testDelete();
            }finally {
                session.close();
            }
        }
    
        /*
        * 添加用户信息
        * */
        public static void testInsert(){
            try{
                SqlSession session = sqlSessionFactory.openSession();
                //获取mapper
                IUser userMapper = session.getMapper(IUser.class);
                System.out.println("Test insert>>>>>>>>>>>>>");
    
                //执行插入
                User user = new User();
                        user.setId(8);
                        user.setName("提莫");
                        user.setAge(5);
                        user.setSex("未知");
                        user.setSchool("约德尔");
                        userMapper.insertUser(user);
    
                        //提交事务
                session.commit();
    
                //插入之后显示用户信息
                System.out.println("after insert>>>>>>>>>>>>");
                getUserList();
                System.out.println("Test insert finished>>>>>>>>>>>>");
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    
        /*
        * 获取用户列表
        * */
        public static void getUserList(){
            try{
                SqlSession session = sqlSessionFactory.openSession();
                IUser iuser = session.getMapper(IUser.class);
                //显示user信息
                System.out.println("Test Get Start>>>>>>>>>>>>");
                printUsers(iuser.getUserList());
                System.out.println("Test get finished>>>>>>>>>>");
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    
    
        public static void testUpdate()
        {
            try
            {
                SqlSession session = sqlSessionFactory.openSession();
                IUser iuser = session.getMapper(IUser.class);
                System.out.println("Test update start...");
                printUsers(iuser.getUserList());
                // 执行更新
                User user = iuser.getUser(8);
                user.setName("New name");
                iuser.updateUser(user);
                // 提交事务
                session.commit();
                // 显示更新之后User信息
                System.out.println("After update");
                printUsers(iuser.getUserList());
                System.out.println("Test update finished...");
            }catch (Exception e)
            {
                e.printStackTrace();
            }
        }
    
    
        // 删除用户信息
        public static void testDelete()
        {
            try
            {
                SqlSession session = sqlSessionFactory.openSession();
                IUser iuser = session.getMapper(IUser.class);
                System.out.println("Test delete start...");
                // 显示删除之前User信息
                System.out.println("Before delete");
                printUsers(iuser.getUserList());
                // 执行删除
                iuser.deleteUser(7);
                // 提交事务
                session.commit();
                // 显示删除之后User信息
                System.out.println("After delete");
                printUsers(iuser.getUserList());
                System.out.println("Test delete finished...");
            }catch (Exception e)
            {
                e.printStackTrace();
            }
        }
    
        /**
         *
         * 打印用户信息到控制台
         *
         * @param users
         */
        private static void printUsers(final List<User> users) {
            int count = 0;
    
            for (User user : users) {
                System.out.println(MessageFormat.format(
                        "============= User[{0}]=================", ++count));
                System.out.println("User Id: " + user.getId());
                System.out.println("User Name: " + user.getName());
                System.out.println("User Age: " + user.getAge());
                System.out.println("User Sex: " + user.getSex());
                System.out.println("User school:" + user.getSchool());
            }
        }
    
    
    }

#### 5、别忘了还有mybatis配置文件。mybatis-remote-config.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>
        <typeAliases>
            <typeAlias alias="User" type="com.xiao.mybatis.bean.User"/>
        </typeAliases>
    
        <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://10.2.17.205:3306/IOTDB?useUnicode=true&characterEncoding=UTF-8"/>
                    <property name="username" value="IOTUSER"/>
                    <property name="password" value="******/>
                </dataSource>
            </environment>
        </environments>
    
    
        <mappers>
            <mapper resource="com/xiao/mybatis/xml/User.xml"/>
        </mappers>
    
    </configuration>

参考教程

[Mybatis增删改查][Mybatis]

[70]: /images/20220520/5871fd211c5e47579506bc1815301eba.png
[Mybatis]: https://www.yiibai.com/mybatis/mybatis-curd.html