Mybatis-CRUD

原始的JDBC太过繁琐，因此出现大量的数据库连接框架，Mybatis就是其中之一
优点：简单易学、简化代码量、SQL写于XML中

代码

1、创建web应用，导入jar包
链接：https://pan.baidu.com/s/1uxLt_FUr2i2v7T7oGMUPLA 
提取码：nrji

创建数据库
create database how2java;
创建表
CREATE TABLE category_ (
  id int(11) NOT NULL AUTO_INCREMENT,
  name varchar(32) DEFAULT NULL,
  PRIMARY KEY (id)
) ENGINE=MyISAM AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
插入数据
INSERT INTO category_ VALUES (null,'category1');
INSERT INTO category_ VALUES (null,'category2');

2、src下创建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>
<!-- 扫描model -->
    <typeAliases>
      <package name="com.llhc.model"/>
    </typeAliases>
 <!-- 连接jdbc -->
    <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/mybatis1?characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
 <!-- 映射文件 -->
    <mappers>
        <mapper resource="com/llhc/model/Category.xml"/>
    </mappers>
</configuration>

3、Category

package com.llhc.model;
public class Category {
    private int id;
    private String name;
    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;
    }
}

4、category.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.llhc.model">
        <insert id="addCategory" parameterType="Category" >
            insert into category_ ( name ) values (#{name})   
        </insert>
         
        <delete id="deleteCategory" parameterType="Category" >
            delete from category_ where id= #{id}  
        </delete>
         
        <select id="getCategory" parameterType="_int" resultType="Category">
            select * from   category_  where id= #{id}   
        </select>
 
        <update id="updateCategory" parameterType="Category" >
            update category_ set name=#{name} where id=#{id}   
        </update>
    </mapper>

5、controller

package com.llhc.controller;
import java.io.IOException;
import java.io.InputStream;
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 com.llhc.model.Category;
 
public class TestMybatis {
 
    public static void main(String[] args) throws IOException {
        System.out.println("fasdfda");
        //1、连接配置文件
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        SqlSession session = sqlSessionFactory.openSession();
        /*2、添加
        session.insert("addCategory",CategoryAdd());*/
        /*3、删除
        session.delete("deleteCategory",CategoryDelete());*/
        /*4、查询
        Category c=session.selectOne("getCategory",2);
        System.out.println(c.getName());*/
       /* 5、修改
        session.update("updateCategory",CategoryUpdate(session));*/
    }
    //添加
    public static Category CategoryAdd(){
        //执行添加操作
        Category c = new Category();
        c.setName("Categoryhehe");
        return c;
    }
    //删除
    public static Category CategoryDelete(){
        //执行删除操作
        Category c = new Category();
        c.setId(3);
        return c;
    }
    //修改
    public static Category CategoryUpdate(SqlSession session){
        Category c=session.selectOne("getCategory",1);
        c.setName("修改成功");
        return c;
    }
}

6、执行测试即可！