Mybatis简单入门

Posted 2022-12-08 SDingBa

转载:
首先是环境的配置，我使用maven创建项目，pom.xml文件如下

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">  
    <modelVersion>4.0.0</modelVersion>  

    <groupId>com.bird</groupId>  
    <artifactId>concursey</artifactId>  
    <version>0.0.1-SNAPSHOT</version>  
    <packaging>jar</packaging>  

    <name>concursey</name>  
    <url>http://maven.apache.org</url>  

    <properties>  
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  
    </properties>  

    <dependencies>  
        <dependency>  
            <groupId>junit</groupId>  
            <artifactId>junit</artifactId>  
            <version>3.8.1</version>  
            <scope>test</scope>  
        </dependency>  

        <dependency>  
            <groupId>org.mybatis</groupId>  
            <artifactId>mybatis</artifactId>  
            <version>3.2.7</version>  
        </dependency>  

        <dependency>  
            <groupId>mysql</groupId>  
            <artifactId>mysql-connector-java</artifactId>  
            <version>5.1.32</version>  
        </dependency>  
    </dependencies>  
</project>  

还得创建一个数据库和对应的一张表做示范，这里就不写了，直接上对应的JavaBean

package com.bird.mybatis.bean;  

public class Users   

    private int id;  
    private String name;  
    private int age;  

    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;  
      

    @Override  
    public String toString()   
        return "Users [id=" + id + ", name=" + name + ", age=" + age + "]";  
      

  

然后要给对应的JavaBean创建对应的mapper.xml文件，内容如下

<?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.bird.mybatis.bean.userMapper">  
    <!--根据ID获取对应的值  -->  
    <select id="getUser" parameterType="int" resultType="com.bird.mybatis.bean.Users">  
        select * from users where id = #id  
    </select>  
</mapper>  

当然还有mybatis的全局文件，conf.xml内容如下

<?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>  
<!-- development:开发模式     work:工作模式 -->  
    <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>  

    <mappers>  
        <mapper resource="com/bird/mybatis/bean/userMapper.xml" />  
    </mappers>  

</configuration>  

最后是测试代码

package com.bird.mybatis.bean;  

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 Test   

    public static void main(String[] args) throws Exception   
        String resource = "conf.xml";  
        Reader reader = Resources.getResourceAsReader(resource);  
        SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader);  
        SqlSession session = sessionFactory.openSession();  
        String statement = "com.bird.mybatis.bean.userMapper.getUser";  
        Users user = session.selectOne(statement, 1);  
        System.out.println(user);  
      
  

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1,xml文件的使用;;
xml文件:

<?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.bird.mybatis.bean.userMapper">  
    <!--CRUD  -->  
    <insert id="insertUser" parameterType="com.bird.mybatis.bean.Users">  
        insert into users(name, age) values(#name, #age);  
    </insert>  

    <delete id="deleteUser" parameterType="int">  
        delete from users where id = #id;  
    </delete>  

    <update id="updateUser" parameterType="com.bird.mybatis.bean.Users">  
        update users set name = #name, age = #age where id = #id;  
    </update>  

    <select id="getUser" parameterType="int" resultType="com.bird.mybatis.bean.Users">  
        select * from users where id = #id;  
    </select>  

    <select id="getAllUser" resultType="com.bird.mybatis.bean.Users">  
        select * from users;  
    </select>  
</mapper>  

package com.bird.mybatis.bean;  

import java.io.IOException;  
import java.io.Reader;  
import java.util.List;  

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.junit.Before;  
import org.junit.Test;  

public class MyTest   

    private SqlSessionFactory factory;  

    @Before  
    public void init()   
        String resource = "conf.xml";  
        Reader reader = null;  
        try   
            reader = Resources.getResourceAsReader(resource);  
         catch (IOException e)   
            e.printStackTrace();  
          
        factory = new SqlSessionFactoryBuilder().build(reader);  
      

    @Test  
    public void testAdd()   
        //默认是手动的   
        SqlSession session = factory.openSession();  
        String statement = "com.bird.mybatis.bean.userMapper.insertUser";  
        int rows = session.insert(statement, new Users(-1, "哈哈", 29));  
        //提交  
        session.commit();  
        System.out.println(rows);  
        session.close();  
      

    @Test  
    public void testUpdate()   
        SqlSession session = factory.openSession();  
        String statement = "com.bird.mybatis.bean.userMapper.updateUser";  
        session.update(statement, new Users(4, "呵呵", 29));  
        session.commit();  
        session.close();  
      

    @Test  
    public void testDelete()   
        SqlSession session = factory.openSession();  
        String statement = "com.bird.mybatis.bean.userMapper.deleteUser";  
        session.delete(statement, 1);  
        session.commit();  
        session.close();  
      

    @Test  
    public void testGetAllUser()   
        SqlSession session = factory.openSession();  
        String statement = "com.bird.mybatis.bean.userMapper.getAllUser";  
        List<Users> list = session.selectList(statement);  
        System.out.println(list.size());  
        session.close();  
      
  

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2 注解的使用:

上使用XML来操作Mybatis实现CRUD，但是大量的XML配置文件的编写是非常烦人的。因此
Mybatis也提供了基于注解的配置方式，下面我们来演示一下使用接口加注解来实现CRUD的的例子。
首先是创建一个接口

package com.bird.mybatis.bean;  

import java.util.List;  

import org.apache.ibatis.annotations.Delete;  
import org.apache.ibatis.annotations.Insert;  
import org.apache.ibatis.annotations.Select;  
import org.apache.ibatis.annotations.Update;  

public interface UserMapper   
    @Insert("insert into users(name, age) values(#name, #age)")  
    public int add(Users user);  

    @Delete("delete from users where id = #id")  
    public int deleteById(int id);  

    @Update("update users set name = #name, age = #age where id = #id")  
    public int update(Users user);  

    @Select("select * from users where id = #id")  
    public Users getUserById(int id);  

    @Select("select * from users")  
    public List<Users> getAllUsers();  
  

<mappers>  
        <mapper resource="com/bird/mybatis/bean/userMapper.xml" />  
        <mapper class="com.bird.mybatis.bean.UserMapper"/>  
    </mappers>  

@Test  
    public void testAdd2()   
        SqlSession openSession = factory.openSession();  
        UserMapper mapper = openSession.getMapper(UserMapper.class);  
        mapper.add(new Users(-1,"娃娃",99));  
        openSession.commit();  
        openSession.close();  
      

h
z转载来着: http://blog.csdn.net/a352193394/article/details/39940259