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Mybatis

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1. Mybatis 介绍

MyBatis 是支持普通 SQL 查询,存储过程和高级映射的优秀持久层框架。MyBatis 消除了几乎所有的 JDBC 代码和参数的手工设置以
及对结果集的检索封装。MyBatis 可以使用简单的 XML 或注解用于配置和原始映射,将接口和 Java 的 POJO(Plain Old Java Objects,
普通的 Java 对象)映射成数据库中的记录.JDBC-->dbutils-->MyBatis-->Hibernate。

2. mybatis 快速入门

  编写第一个基于 mybaits 的测试例子:

2.1. 添加 jar 包

【mybatis】
  mybatis-3.1.1.jar
【MYSQL 驱动包】
  mysql-connector-java-5.1.7-bin.jar
 

2.2. 建库+表

  
create database mybatis;
use mybatis;
CREATE TABLE users(
    id INT PRIMARY KEY AUTO_INCREMENT,
    NAME VARCHAR(20),
    age INT
);

INSERT INTO users(NAME, age) VALUES(Tom, 12);
INSERT INTO users(NAME, age) VALUES(Jack, 11);

 

2.3. 添加 Mybatis 的配置文件 conf.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/mybatis" />
        <property name="username" value="root" />
        <property name="password" value="root" />
      </dataSource>
    </environment>
  </environments>
</configuration>

 

 

2.4. 定义表所对应的实体类

public class Users {

        private int id;
        private String name;
        private int age;
        //get,set 方法
        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 Users(int id, String name, int age) {
            this.id = id;
            this.name = name;
            this.age = age;
        }
        public Users() {
            
        }
        public Users(String name, int age) {
            this.name = name;
            this.age = age;
        }
        @Override
        public String toString() {
            return "Users [id=" + id + ", name=" + name + ", age=" + age + "]";
        }
}

 

2.5. 定义操作 users 表的 sql 映射文件 userMapper.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="com.zhiyou100.hhz.mapper.UsersMapper">
  <select id="getUser" parameterType="int" resultType="com.zhiyou100.hhz.bean.Users">
    select * from users where id=#{id}
  </select>
  <insert id="addUser" parameterType="com.zhiyou100.hhz.bean.Users">
    insert into users(name,age) value(#{name},#{age})
  </insert>
  <update id="updateUser" parameterType="com.zhiyou100.hhz.bean.Users">
    update Users set name=#{name},age=#{age} where id=#{id}
  </update>
  <delete id="deleteUser" parameterType="int">
    delete from Users where id=#{id}
  </delete>
  <select id="getUserAll" resultType="com.zhiyou100.hhz.bean.Users">
    select * from users
  </select>
  <select id="selectUserByAge" parameterType="java.util.Map" resultType="com.zhiyou100.hhz.bean.Users">
    <![CDATA[select * from users where age>=10 and age<=30]]>
  </select>
</mapper>

 

2.6. 在 conf.xml 文件中注册 userMapper.xml 文件

在</configuration>标签上写
<mappers>
    <mapper resource="com/zhiyou100/hhz/mapper/UsersMapper.xml" />
</mappers>

 

2.7. 编写测试代码:执行定义的 select 语句等

class UsersTest {

    final String str="com.zhiyou100.hhz.mapper.UsersMapper.";
    static SqlSession session = null;
    
    @BeforeAll
    static void setUpBeforeClass() throws Exception {
        Reader reader = Resources.getResourceAsReader("conf.xml");
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);
        session = sessionFactory.openSession();
    }

    @Test
    void test1() {
        Users users = session.selectOne(str+"getUser",1);
        System.out.println(users);
    }
    @Test
    void test2() {
        session.insert(str+"addUser",new Users("朱华龙",1));
    }
    @Test
    void test3() {
        session.update(str+"updateUser",new Users(1,"王玉芳",25));
    }
    @Test
    void test4() {
        session.delete(str+"deleteUser",6);
    }
    @Test
    void testselectAll() {
        List<Users> list = session.selectList(str+"getUserAll");
        for(Users users:list) {
            System.out.println(users);
        }
    }
    @Test
    void testselectByAge() {
        Map<String, Integer> map=new HashMap<String,Integer>();
        map.put("min", 10);
        map.put("max", 30);
        List<Users> list = session.selectList(str+"selectUserByAge",map);
        for(Users users:list) {
            System.out.println(users);
        }
        
    }
    @AfterAll
    static void tearDownAfterClass() throws Exception {
        session.commit();
    }

 

Mybatis

原文:https://www.cnblogs.com/zfyyfw/p/11438301.html

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