MyBatis框架零基础快速入门案例详解

mysql> create database ssm;

Query OK, 1 row affected (0.01 sec)

mysql> use ssm

Database changed

mysql> CREATE TABLE `student` (

     ->  `id` int (11) NOT NULL ,

     ->  ` name ` varchar (255) DEFAULT NULL ,

     ->  `email` varchar (255) DEFAULT NULL ,

     ->  `age` int (11) DEFAULT NULL ,

     ->  PRIMARY KEY (`id`)

     -> ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Query OK, 0 rows affected, 3 warnings (0.03 sec)

< dependencies >

  < dependency >

< groupId >junit</ groupId >

  < artifactId >junit</ artifactId >

  < version >4.11</ version >

  < scope >test</ scope >

</ dependency >

  < dependency >

  < groupId >org.mybatis</ groupId >

  < artifactId >mybatis</ artifactId >

  < version >3.5.1</ version >

</ dependency >

  < dependency >

  < groupId >mysql</ groupId >

  < artifactId >mysql-connector-java</ artifactId >

  < version >5.1.9</ version >

  </ dependency >

  </ dependencies >

< build >

< resources >

  < resource >

  < directory >src/main/java</ directory > <!--所在的目录-->

  < includes > <!--包括目录下的.properties,.xml 文件都会扫描到-->

  < include >**/*.properties</ include >

  < include >**/*.xml</ include >

  </ includes >

  < filtering >false</ filtering >

  </ resource >

</ resources >

  < plugins >

  < plugin >

  < artifactId >maven-compiler-plugin</ artifactId >

  < version >3.1</ version >

  < configuration >

  < source >1.8</ source >

  < target >1.8</ target >

  </ configuration >

  </ plugin >

  </ plugins >

</ build >

package com.bjpowernode.domain;

/**

  * <p>Description: 实体类 </p>

  * <p>Company: http://www.bjpowernode.com

  */

public class Student {

  //属性名和列名一样

  private Integer id;

  private String name;

  private String email;

  private Integer age;

  // set ,get , toString

}

package com.bjpowernode.dao;

import com.bjpowernode.domain.Student;

import java.util.List;

/*

  * <p>Description: Dao 接口 </p>

  * <p>Company: http://www.bjpowernode.com

  */

public interface StudentDao {

  /*查询所有数据*/

  List<Student> selectStudents();

}

<? 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">

<!--

  namespace：必须有值，自定义的唯一字符串

  推荐使用：dao 接口的全限定名称

-->

< mapper namespace = "com.Example.dao.StudentDao" >

  <!--

  <select>: 查询数据， 标签中必须是 select 语句

  id: sql 语句的自定义名称，推荐使用 dao 接口中方法名称，

  使用名称表示要执行的 sql 语句

  resultType: 查询语句的返回结果数据类型，使用全限定类名

  -->

  < select id = "selectStudents"

resultType = "com.Example.domain.Student" >

  <!--要执行的 sql 语句-->

  select id,name,email,age from student

  </ select >

</ mapper >

<? 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 >

  <!--配置 mybatis 环境-->

  < environments default = "mysql" >

  <!--id:数据源的名称-->

  < environment id = "mysql" >

  <!--配置事务类型：使用 JDBC 事务（使用 Connection 的提交和回

滚）-->

  < transactionManager type = "JDBC" />

  <!--数据源 dataSource：创建数据库 Connection 对象

  type: POOLED 使用数据库的连接池

  -->

  < dataSource type = "POOLED" >

  <!--连接数据库的四个要素-->

  < property name = "driver" value = "com.mysql.jdbc.Driver" />

  < property name = "url"

value = "jdbc:mysql://localhost:3306/ssm" />

  < property name = "username" value = "root" />

  < property name = "password" value = "123456" />

  </ dataSource >

  </ environment >

  </ environments >

  < mappers >

  <!--告诉 mybatis 要执行的 sql 语句的位置-->

  < mapper resource = "com/Example/dao/StudentDao.xml" />

  </ mappers >

</ configuration >

/*

* mybatis 入门

*/

@Test

public void testStart() throws IOException {

  //1.mybatis 主配置文件

  String config = "mybatis-config.xml" ;

  //2.读取配置文件

  InputStream in = Resources.getResourceAsStream(config);

  //3.创建 SqlSessionFactory 对象,目的是获取 SqlSession

  SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);

  //4.获取 SqlSession,SqlSession 能执行 sql 语句

  SqlSession session = factory.openSession();

  //5.执行 SqlSession 的 selectList()

  List<Student> studentList =

session.selectList( "com.bjpowernode.dao.StudentDao.selectStudents" );

  //6.循环输出查询结果

  studentList.forEach( student -> System.out.println(student));

  //7.关闭 SqlSession，释放资源

  session.close();

}

< settings >

  < setting name = "logImpl" value = "STDOUT_LOGGING" />

</ settings >

int insertStudent(Student student);

< insert id = "insertStudent" >

  insert into student(id,name,email,age)

values(#{id},#{name},#{email},#{age})

</ insert >

@Test

public void testInsert() throws IOException {

  //1.mybatis 主配置文件

  String config = "mybatis-config.xml" ;

  //2.读取配置文件

  InputStream in = Resources.getResourceAsStream(config);

  //3.创建 SqlSessionFactory 对象

  SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);

  //4.获取 SqlSession

  SqlSession session = factory.openSession();

  //5.创建保存数据的对象

  Student student = new Student();

  student.setId( 1005 );

  student.setName( "张丽" );

  student.setEmail( "zhangli@163.com" );

  student.setAge( 20 );

  //6.执行插入 insert

  int rows = session.insert(

"com.bjpowernode.dao.StudentDao.insertStudent" ,student);

  //7.提交事务

  session.commit();

  System.out.println( "增加记录的行数:" +rows);

  //8.关闭 SqlSession

  session.close();

}