（6）Mybatis - 修改删除，id查询，模糊查询，总个数查询

1 修改和删除操作

1. UserDao
   

2. xml
   

注意:
1.在映射文件中，我们的parameterType是Integer
2.在delete映射文件中，如果我们的参数只有一个，比如Interger userId 那么我们只需要写清楚占位符就行
了， 随便取什么都可以 where id = #{ uid }

3. 测试类：
   

4. 更新结果显示：

5. 删除操作显示：
   

2 根据Id查询信息：

3 根据名称模糊查询信息

注意：如果用底下这种方式查询的话 里面的值必须写成value， 因为已经绑定了的。

两者的区别：

4 查询总记录条数

5 总体结构

1. pom

<?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</groupId>
    <artifactId>day2-mybatis</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>



    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.6</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

    </dependencies>


</project>

2. log4j.properties

log4j.rootCategory=debug, CONSOLE, LOGFILE

log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30C %x - %m\n

3. SqlMapConfig.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">
<!--首先是跟元素-->
<configuration>
    <!--配置环境 , 选择一个默认的环境mysql-->
    <environments default="mysql">
        <!--配置mysql的环境-->
        <environment id="mysql">
            <!--配置事务-->
            <transactionManager type="JDBC"></transactionManager>
            <!--配置连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"></property>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?characterEncoding=UTF-8" />
                <property name="username" value="root"></property>
                <property name="password" value=""></property>
            </dataSource>
                
        </environment>
    </environments>

    <!--配置映射文件的位置-->
    <mappers>
        <mapper resource="com/dao/UserDao.xml"></mapper>
    </mappers>

</configuration>

4. User

package com.domain;

import java.io.Serializable;

//让它实现序列化接口
public class User implements Serializable {
    private Integer id;
    private String username;
    private String birthday;
    private String sex;
    private String address;

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", birthday='" + birthday + '\'' +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }

    public Integer getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getBirthday() {
        return birthday;
    }

    public void setBirthday(String birthday) {
        this.birthday = birthday;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

5. UserDao

package com.dao;

import com.domain.User;

import java.util.List;

/**
 * 用户的持久层
 */
public interface UserDao {

    /**
     * 查询所有的用户
     */
    List<User> findAll();

    /**
     * 保存方法
     */
    void saveUser(User user);

    /**
     * 更新操作
     */
    void updateUser(User user);

    /**
     * 删除操作
     */
    void deleteUser(Integer userId);

    /**
     *  根据id查询用户信息
     */
    User findById(Integer userId);


    /**
     * 根据名称模糊查询信息
     */
    List<User> findByName(String username);

    /**
     * 查询总用户数
     */
    int findTotal();



}

6. UserDao.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.dao.UserDao">
    <!--配置查询所有-->
    <select id="findAll" resultType="com.domain.User">
        select * from user;
    </select>
    
    <!--保存用户-->
    <insert id="saveUser" parameterType="com.domain.User">
        insert into user(username,address,sex,birthday) value(#{username},#{address},#{sex},#{birthday});
    </insert>

    <!--更新用户-->
    <update id="updateUser" parameterType="com.domain.User">
        update user set username=#{username},address=#{address},sex=#{sex},birthday=#{birthday} where id=#{id};
    </update>

    <!--删除用户-->
    <delete id="deleteUser" parameterType="java.lang.Integer">
        delete from user where id = #{uid};
    </delete>

    <!--根据ID查询用户-->
    <select id="findById" parameterType="INT" resultType="com.domain.User">
        select * from user where id = #{uid};
    </select>

    <select id="findByName" parameterType="string" resultType="com.domain.User">

        <!--select * from user where username like #{name};-->
        select * from user where username like '%${value}%'
    </select>

    <!--获取用户的总记录条数-->
    <select id="findTotal" resultType="int">
        select count(id) from user;
    </select>

</mapper>

7. MybatisTest

import com.dao.UserDao;
import com.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.After;
import org.junit.Before;
import org.junit.Test;

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

public class MybatisTest {


    private InputStream in;
    private SqlSession sqlSession;
    private UserDao userDao;

    @Before//用于在测试方法之前执行
    public void init()throws Exception{
        //1.读取配置文件，生成字节输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.获取SqlSessionFactory
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        //3.获取SqlSession对象
        sqlSession = factory.openSession();
        //4.获取dao的代理对象
        userDao = sqlSession.getMapper(UserDao.class);
    }

    @After//用于在测试方法之后执行
    public void destory()throws Exception{
        //5.提交事务
        sqlSession.commit();
        //6.释放资源
        sqlSession.close();
        in.close();
    }
    /**
     * 测试查询所有
     */
    @Test
    public void testFindAll(){
        //5.执行查询所有方法
        List<User> users = userDao.findAll();
        for(User user: users){
            System.out.println(user);
        }
    }

    /**
     * 测试保存操作
     */
    @Test
    public void testSave()throws Exception{
        User user = new User();
        user.setUsername("test");
        user.setAddress("成都市");
        user.setSex("男");
        user.setBirthday("2019");
        //5.执行查询所有方法
        userDao.saveUser(user);
    }

    /**
     * 测试更新操作
     */
    @Test
    public void testUpdate(){
        User user = new User();
        user.setId(49);
        user.setUsername("update");
        user.setSex("male");
        user.setBirthday("2020");
        user.setAddress("chengdu");

        //5.执行保存方法
        userDao.updateUser(user);

    }

    /**
     * 测试删除操作
     */
    @Test
    public void testDelete(){
        //5.执行删除操作
        userDao.deleteUser(42);
    }


    /**
     * 测试根据ID查询用户
     */
    @Test
    public void testFindOne(){
        User user = userDao.findById(43);
        System.out.println(user);
    }

    /**
     * 测试模糊查询操作
     */
    @Test
    public void testFindByName(){
        List<User> users = userDao.findByName("王");
        for(User user: users){
            System.out.println(user);
        }
    }

    /**
     * 查询总记录条数
     */
    @Test
    public void testFindTotal(){
        int count = userDao.findTotal();
        System.out.println(count);
    }
}