mybatis非接口开发helloworld--最基本单表crud包括获得插入返回id,#$注入的区别

Jar包导入,生成数据库表,创建与src同级资源目录config,test目录(注意,config,test均为资源目录)


在这里非接口开发和hibernate玩起来一模一样,也是先创建实体类DBUser,再建实体类对应的映射文件DBUser.xml(局部xml文件),再将DBUser.xml mapper到SqlMapConfig.xml(全局配置文件),再弄个测试类Demo1来测下

实体类:DBUser.java

package com.xiangshuai.mybatis;

 

import java.util.Date;

 

public classDBUser {

    private int id;

    private Integer sex;

    private Date birthday;

    private String address;

    private String username;

   

    public DBUser(Integer sex, Date birthday, String address, String username) {

        super();

        this.sex = sex;

        this.birthday = birthday;

        this.address = address;

        this.username = username;

    }

 

    public DBUser() {

        super();

        // TODO Auto-generated constructor stub

    }

 

    public String getUsername() {

        return username;

    }

 

    public void setUsername(String username) {

        this.username = username;

    }

 

    public int getId() {

        return id;

    }

 

    public void setId(int id) {

        this.id = id;

    }

 

    public Integer getSex() {

        return sex;

    }

 

    public void setSex(Integer sex) {

        this.sex = sex;

    }

 

    public Date getBirthday() {

        return birthday;

    }

 

    public void setBirthday(Date birthday) {

        this.birthday = birthday;

    }

 

   

 

    public String getAddress() {

        return address;

    }

 

    public void setAddress(String address) {

        this.address = address;

    }

 

    @Override

    public String toString() {

        return "DBUser [id="+ id + ", sex="+ sex+ ", birthday=" + birthday+ ", address=" + address+ ", username="

                +username + "]";

    }

}

 

建实体类对应的映射文件DBUser.xml(局部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">

<!-- namespace:命名空间,对statement的信息进行分类管理 -->

<!-- 注意:在mapper代理时,它具有特殊及重要的作用 -->

<mapper namespace="test">

    <!-- 根据用户ID查询用户信息 -->

    <!-- select:表示一个MappedStatement对象 -->

    <!-- idstatement的唯一标示 -->

    <!-- #{}:表示一个占位符? -->

    <!-- #{id}:里面的id表示输入参数的参数名称,如果该参数是简单类型,那么#{}里面的参数名称可以任意 -->

    <!-- parameterType:输入参数的java类型 -->

    <!-- resultType:输出结果的所映射的java类型(单条结果所对应的java类型) -->

    <select id="findDBUserById" parameterType="int"

        resultType="com.xiangshuai.mybatis.DBUser">

        SELECT* FROM DBUSER WHERE id =#{id}

    </select>

   

    <update id="udateDBUser" parameterType="com.xiangshuai.mybatis.DBUser">

           UPDATE DBUSER SET username=#{username},sex=#{sex},birthday=#{birthday},address=#{address}where id=#{id}

    </update>

   

    <delete id="deleteDBUser" parameterType="int">

            DELETE FROM DBUSER WHERE id=#{id}

    </delete>

   

    <!-- 增加后入参的dbuser对象仍然没有带id,如果要数据库持久化后入参带id,则需要在insert标签中加seleteKey标签从数据库中将id

    查出来再赋予给入参下个id="insertDBUser1"就是mysql主键是int类型自增就是这样的 -->

    <insert id="insertDBUser" parameterType="com.xiangshuai.mybatis.DBUser">

         INSERT INTO DBUSER

         (username,birthday,sex,address)

            VALUES(#{username},#{birthday},#{sex},#{address});

    </insert>

 

    <!-- 根据用户名称模糊查询用户列表 -->

    <!-- ${}:表示一个sql的连接符,会原样输出,而#{}会转成varchar也就是String类型

    比如一个idint类型id=3  #{id}后会变成'3' ${value}就是3-->

    <!-- ${value}:里面的value表示输入参数的参数名称,如果该参数是简单类型,那么${}里面的参数名称必须是value -->

    <!-- ${}这种写法存在sql注入的风险,所以要慎用!!但是在一些场景下,必须使用${},比如排序时,动态传入排序的列名,${}会原样输出,-->

    <select id="findDBUsersByName" parameterType="java.lang.String"

        resultType="com.xiangshuai.mybatis.DBUser">

        SELECT* FROM DBUSER WHERE username LIKE '%${value}%'

    </select>

   

    <select id="findDBUsersByName2" parameterType="java.lang.String"

        resultType="com.xiangshuai.mybatis.DBUser">

        SELECT* FROM DBUSER WHERE USERNAME LIKE '%${value}%'

    </select>

 

    <!-- 添加用户 -->

    <!-- selectKey:查询主键,在标签内需要输入查询主键的sql -->

    <!-- order:指定查询主键的sqlinsert语句的执行顺序,相当于insert语句来说

    AFTER之后也就是在执行完insert完成持久化记录之后  将这条记录的id查出来再赋值给入参参数DBUse对象 -->

    <!-- LAST_INSERT_ID:该函数是mysql的函数,获取自增主键的ID,它必须配合insert语句一起使用  -->

    <insert id="insertDBUser1" parameterType="com.xiangshuai.mybatis.DBUser">

        <selectKey keyProperty="id" resultType="int"order="AFTER">

            SELECTLAST_INSERT_ID()

        </selectKey>

   

        INSERTINTO DBUSER

        (username,birthday,sex,address)

        VALUES(#{username},#{birthday},#{sex},#{address})

    </insert>

   

    <!-- 自增主键之UUID -->

    <insert id="insertDBUser2" parameterType="com.xiangshuai.mybatis.DBUser">

        <selectKey keyProperty="id" resultType="string"order="BEFORE">

            SELECTUUID()

        </selectKey>

   

        INSERTINTO DBUSER

        (id,username,birthday,sex,address)

        VALUES(#{id},#{username},#{birthday},#{sex},#{address})

    </insert>

   

    <!-- 自增主键之UUID oralce序列自增-->

    <insert id="insertDBUser3" parameterType="com.xiangshuai.mybatis.DBUser">

        <selectKey keyProperty="id" resultType="int"order="BEFORE">

            SELECTseq.nextval FROM dual

        </selectKey>

   

        INSERTINTO DBUSER

        (id,username,birthday,sex,address)

        VALUES(#{id},#{username},#{birthday},#{sex},#{address})

    </insert>

</mapper>

 

SqlMapConfig.xml(全局配置文件)

<?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>

 

    <!-- 加载java的配置文件或者声明属性信息 -->

    <properties resource="db.properties">

    </properties>

 

    <!-- <settings></settings> -->

 

    <!-- 自定义别名 -->

    <!-- <typeAliases>

        单个别名定义

        <typeAliastype="com.itheima.mybatis.po.User" alias="user"/>

 

        批量别名定义(推荐)

        package:指定包名称来为该包下的po类声明别名,默认的别名就是类名(首字母大小写都可)

        <packagename="com.itheima.mybatis.po" />

    </typeAliases>

 -->

    <!-- 配置mybatis的环境信息,与spring整合,该信息由spring来管理 -->

    <environments default="development">

        <environment id="development">

            <!-- 配置JDBC事务控制,由mybatis进行管理 -->

            <transactionManager type="JDBC"></transactionManager>

            <!-- 配置数据源,采用mybatis连接池 -->

            <dataSource type="POOLED">

                <property name="driver" value="${db.driver}"/>

                <property name="url" value="${db.url}"/>

                <property name="username" value="${db.username}"/>

                <property name="password" value="${db.password}"/>

            </dataSource>

        </environment>

    </environments>

 

    <!-- 加载映射文件 -->

    <mappers>

        <mapper resource="DBUser.xml" />

    <!-- <mapper resource="mapper/UserMapper.xml"/> -->

 

        <!-- 批量加载映射文件 -->

        <!-- <packagename="com.itheima.mybatis.mapper" /> -->

    </mappers>

</configuration>

 

测试类Demo1

package com.xiangshuai.test;

 

import java.io.IOException;

import java.io.InputStream;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Date;

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;

 

import com.xiangshuai.mybatis.DBUser;

 

public classDemo1 {

     /*mybatis开发方式1查询,操作和hibernate很像,也是先造实体类,然后配实体类的XML映射文件,然后将实体类的XML映射文件mapper到全局映射 XML文件

      SqlMapConfig.xml中去,

      * */

    private SqlSessionFactory sqlSessionFactory;

    private SqlSession sqlSession;

    //before在每个执行@Test之前都会执行的方法

    @Before

    public void before(){

        //读取配置文件

        //全局配置文件的路径

        Stringresource = "SqlMapConfig.xml";

        InputStreaminputStream = null;

        try {

            inputStream = Resources.getResourceAsStream(resource);

        }catch(IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

       

        //创建SqlSessionFactory

         sqlSessionFactory = newSqlSessionFactoryBuilder().build(inputStream);

       

        //创建SqlSession

        sqlSession = sqlSessionFactory.openSession();

    }

    @Test

    public void findDBUserById(){

               

                //调用SqlSession的增删改查方法

                //第一个参数:表示statement的唯一标示,namespace.id(DBUser.xmlsql标签 id)

                DBUseruser = sqlSession.selectOne("test.findDBUserById",1);

                System.out.println(user);

               

                //关闭资源

                sqlSession.close();

    }

    //模糊查询之 like '%${value}%',之所以不用 %#{username}%是因为 mybatis #{username}转成 %''%而不是像${}原样输出

    @Test

   public void findDBUserByUsername(){

               

                //调用SqlSession的增删改查方法

                //第一个参数:表示statement的唯一标示,namespace.id(DBUser.xmlsql标签 id)

                List<DBUser> users = sqlSession.selectList("test.findDBUsersByName2", "");

                System.out.println(users);

               

                //关闭资源

                sqlSession.close();

   }

   

    @Test

    public void updateDBUser(){

        //调用SqlSession的增删改查方法

        //第一个参数:表示statement的唯一标示,namespace.id(DBUser.xmlsql标签 id)

        DBUseruser = sqlSession.selectOne("test.findDBUserById",1);

        user.setUsername("王小二");user.setSex(2);user.setBirthday(new Date());user.setAddress("广东广州");

        sqlSession.insert("test.udateDBUser",user);

        sqlSession.commit();

        //关闭资源

        sqlSession.close();

    }

    @Test

    public void deleteDBUserById(){

        sqlSession.delete("test.deleteDBUser",32);

        sqlSession.commit();

        //关闭资源

        sqlSession.close();

    }

    //insert标签中不加selectKey标签,不返回iddbuser对象的增加测试

    @Test

    public void insertUser() throws ParseException{

        SimpleDateFormatsdf = new SimpleDateFormat("yyyy-MM-dd");

        Dateda = sdf.parse("1997-11-12");

        DBUseruser = new DBUser(1,da,"广西梧州","刘小诗");

        sqlSession.insert("test.insertDBUser",user);

        sqlSession.commit();

        sqlSession.close();

        System.out.println(user);//打印结果无id,但数据库中已经有这条id记录  DBUser [id=0,sex=1, birthday=Wed Nov 12 00:00:00 CST 1997, address=广西梧州, username=刘小诗]

    }

    //insert标签中加selectKey标签,并且order="AFTER"表示在insert持久化后将这条记录的id查出粜,赋给入参 dbuser对象的增加测试

    @Test

    public void insertUserHaveId() throws ParseException{

        SimpleDateFormatsdf = new SimpleDateFormat("yyyy-MM-dd");

        Dateda = sdf.parse("1997-11-13");

        DBUseruser = new DBUser(1,da,"北京西城","刘诗诗");

        sqlSession.insert("test.insertDBUser1",user);

        sqlSession.commit();

        sqlSession.close();

        System.out.println(user);//打印结果带idDBUser [id=36, sex=1,birthday=Thu Nov 13 00:00:00 CST 1997, address=北京西城, username=刘诗诗]

    }

}

 

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转载自blog.csdn.net/xiangshuai198807/article/details/78637537