mybatis

SSM

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　　java web 框架

　　spring　　　　//业务层框架

　　spring MVC　　//开发web程序应用的模块model+ view +controller模块化编程。模型视图控制器展现部分放到一个模块中去，控制的部分放到一个文件中去，数据部分放到一个数据模块中去。当改变数据的时候前面的状态会有变化。

　　Mybatis　　　　//数据持久化技术。jcbc，mysql

一、mybatis

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　　前身ibatis.对jdbc的封装，

　　

1.体验ibatis

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　　　　1.创建项目和模块

　　　　2.添加pom文件　　　　

<?xml version="1.0" encoding="UTF-8"?>
<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.it18zhang</groupId>
    <artifactId>idea-bigdata-project4</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.2.1</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.17</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>
</project>

　　　　3.XML 配置文件（configuration XML）中包含了对 MyBatis 系统的核心设置，包含获取数据库连接实例的数据源（DataSource）和决定事务作用域和控制方式的事务管理器（TransactionManager）。XML 配置文件的详细内容后面再探讨，这里先给出一个简单的示例：

　　　　打开mysql:创建数据库：create database mybatis ;　　//
            create table users(id int primary_key,name varchar(20),age int)//创建表

　　　　[resources/mybatis-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>
  <environments default="development">
    <environment id="development">
      <transactionManager type="JDBC"/>
      <dataSource type="POOLED">
        <property name="driver" value="${driver}"/>
        <property name="url" value="${url}"/>
        <property name="username" value="${username}"/>
        <property name="password" value="${password}"/>
      </dataSource>
    </environment>
  </environments>
  <mappers>
    <mapper resource="org/mybatis/example/BlogMapper.xml"/>
  </mappers>
</configuration>

　　4.创建库和表

　　5.API编程测试连接

package com.it18zhang.mybatisdemo;

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.InputStream;

/**
 * Created by stone on 2018/9/19.
 */
public class App {
    public static void main(String[] args){
        try{
            //指定配置文件的路径(类路径)
            String resource = "mybatis-config.xml";
            //加载文件
            InputStream inputStream = Resources.getResourceAsStream(resource);
            //创建回话工厂Builder,相当于连接池
            SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);
            //通过sf开启会话，相当于打开连接
            SqlSession s=sf.openSession();
            System.out.println(s);

        } catch(Exception e ){
            e.printStackTrace();
        }
    }
}

　　6.编写映射文件

　　　　a.创建User类，和User表对应

package com.it18zhang.mybatisdemo.domain;

/**
 * Created by stone on 2018/9/19.
 */
public class User {
    private Integer id ;
    private String name ;
    private int age ;

    public Integer getId() {
        return id;
    }

    public void setId(Integer 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;
    }
}

　　　　b.创建UserMapper.xml文件

　　　　[com/it18zhang/mybatisdemo/domain/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="users ">
    <insert id="insert" >
        insert into users(name,age) values(#{NAME},#{age})
    </insert>
</mapper>

　　　　c.通过映射来进行数据库的CRUD

package com.it18zhang.mybatisDemo;

import com.it18zhang.mybatisdemo.domain.User;
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.Test;

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

/**
 * Created by stone on 2018/9/19.
 */
public class testCRUD {
    /*
    *
    * insert
    * */
    @Test
    public void insert(){
        try {
            //添加配置文件(加载类路径)
            String resources = "mybatis-config.xml";
            //加载文件
            InputStream inputStream = Resources.getResourceAsStream(resources);
            //创建会话工厂Builder，相当于连接池
            SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);
            //通过sf开启会话，相当于打开连接
            SqlSession s = sf.openSession();
            User u = new User();
            u.setId(2);
            u.setName("jerry");
            u.setAge(13);
            s.insert("users.insert",u);
            s.commit();
            s.close();

        } catch (IOException e) {
            e.printStackTrace();
        }


    }
    /*
    * uodate
    * */
    @Test
    public void update(){
        try {
            //添加配置文件(加载类路径)
            String resources = "mybatis-config.xml";
            //加载文件
            InputStream inputStream = Resources.getResourceAsStream(resources);
            //创建会话工厂Builder，相当于连接池
            SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);
            //通过sf开启会话，相当于打开连接
            SqlSession s = sf.openSession();
            User u = new User();
            u.setId(2);
            u.setName("stone");
            u.setAge(23);
            s.update("users.update",u);
            s.commit();
            s.close();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    /*
    * SelectOne
    * */
    @Test
    public void selectOne(){
        try {
            //添加配置文件(加载类路径)
            String resources = "mybatis-config.xml";
            //加载文件
            InputStream inputStream = Resources.getResourceAsStream(resources);
            //创建会话工厂Builder，相当于连接池
            SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);
            //通过sf开启会话，相当于打开连接
            SqlSession s = sf.openSession();
            User u = s.selectOne("users.selectOne",1);
            System.out.println(u.getName());
            s.commit();
            s.close();

        } catch (IOException e) {
            e.printStackTrace();
        }


    }
    @Test
    public void selectAll(){
        try {
            //添加配置文件(加载类路径)
            String resources = "mybatis-config.xml";
            //加载文件
            InputStream inputStream = Resources.getResourceAsStream(resources);
            //创建会话工厂Builder，相当于连接池
            SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);
            //通过sf开启会话，相当于打开连接
            SqlSession s = sf.openSession();
            List<User> users = s.selectList("users.selectAll");
            for(User u : users){
                System.out.println(u.getName()+":"+u.getAge());
            }
            s.commit();
            s.close();

        } catch (IOException e) {
            e.printStackTrace();
        }


    }
}

　　　d在数据库中运行脚本：source e:/sql.sql

二、复杂应用

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　　1.准备数据：sql.sql

　　2.创建java bean

　　　　(1)User

package com.it18zhang.mybatisdemo.domain;

/**
 * Created by stone on 2018/9/19.
 */
public class User {
    private Integer id ;
    private String name ;
    private int age ;

    public Integer getId() {
        return id;
    }

    public void setId(Integer 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;
    }
}

　　(2)Order

package com.it18zhang.mybatisdemo.domain;

/**
 *订单类
 */
public class Order {
    private Integer id;
    private String orderNo;
    //建立关联关系
    private User user ;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getOrderNo() {
        return orderNo;
    }

    public void setOrderNo(String orderNo) {
        this.orderNo = orderNo;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }
}

　　(4)Item

package com.it18zhang.mybatisdemo.domain;

/**
 * Created by stone on 2018/9/20.
 */
public class Item {
    private Integer id;
    private String  itemName;
　　//订单项和订单之间的关联查询
    private Order order;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getItemName() {
        return itemName;
    }

    public void setItemName(String itemName) {
        this.itemName = itemName;
    }

    public Order getOrder() {
        return order;
    }

    public void setOrder(Order order) {
        this.order = order;
    }
}

　　3.创建Order映射文件

　　　　[resource/OrderMapper.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="orders">
    <insert id="insert" >
        insert into orders(orderno,uid) values(#{orderNo},#{user.id})
    </insert>
</mapper>

　　4.修改配置文件，添加映射

　　[resource/mybatis.xml]

 <!--引入映射文件-->
    <mappers>
        <mapper resource="*Mapper.xml"/>
    </mappers>