Java框架_Mybatis_day02_CRUD操作

上接：Java框架_Mybatis_day01

目录

四、Mybatis的CRUD操作

4.1 依赖管理

4.2 User 实体类

4.3 UserDao接口（持久化层）

4.4 sqlMapConfig.xml 配置文件

4.5 UserDao.xml映像文件

4.6 log4j.properties 日志配置文件

4.7 TestUserDao 测试类

4.8 项目结构

---

四、Mybatis的CRUD操作

4.1 依赖管理

<?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.cpz</groupId>
    <artifactId>mybatis_day01_crud</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.18</version>
        </dependency>
        <!-- 日志坐标 -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        <!--测试-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
    </dependencies>
</project>

4.2 User 实体类

package com.cpz.domain;

import java.io.Serializable;
import java.util.Date;

public class User implements Serializable {
    private int id;// 主键ID
    private String username;// 用户姓名
    private String sex;// 性别
    private Date birthday;// 生日
    private String address;// 地址

    public int getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

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

    public String getSex() {
        return sex;
    }

    public void setSex(String 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 "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", sex='" + sex + '\'' +
                ", birthday=" + birthday +
                ", address='" + address + '\'' +
                '}';
    }
}

4.3 UserDao接口（持久化层）

package com.cpz.dao;

import com.cpz.domain.User;

import java.util.List;

public interface UserDao {
    // 查询所有
    public List<User> findAll();

    // 保存
    public void saveUser(User user);

    // 修改
    public void updateUser(User user);

    // 删除
    public void deleteUser(Integer id);

    // 主键查询
    public User findUserById(Integer id);

    // 模糊查询（方案一）
    public List<User> findUserByUserNameLike1(String username);

    // 模糊查询（方案二）
    public List<User> findUserByUserNameLike2(String username);

    // 查询数量
    public int findCount();

}

4.4 sqlMapConfig.xml 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">
<!--mybatis的核心配置文件-->
<configuration>
    <!--配置连接数据库的环境-->
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"></property>
                <property name="url" value="jdbc:mysql:///test"></property>
                <property name="username" value="root"></property>
                <property name="password" value="1234"></property>
            </dataSource>
        </environment>
    </environments>
    <!--加载映射文件-->
    <mappers>
        <mapper resource="com/cpz/dao/UserDao.xml"></mapper>
    </mappers>
</configuration>

4.5 UserDao.xml映像文件

<?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">
<!--建立映射：建立Dao中的方法（namespace+id）和数据库sql执行的映射（查询的结果封装到实体中）-->
<mapper namespace="com.cpz.dao.UserDao">
    <!--查询所有
        namespace="com.itheima.dao.UserDao"：表示类名的路径
        id="findAll"：表示方法名
        resultType="com.itheima.domain.User"：结果集的类型封装，封装到User实体中（实体中的属性和数据库表的字段一致）
    -->
    <select id="findAll" resultType="com.cpz.domain.User">
        select * from user
    </select>
    <!-- 保存
        parameterType：参数类型映射
        #{username},#{birthday},#{sex},#{address}：表示OGNL表达式，用对象图导航语言，使用#{}读取User中的属性值
        保存之后，将id查询的值，封装到实体中的id属性中
        selectKey：
            keyProperty="id"：封装到id的属性中
            keyColumn="id"：查询的列的名称
            resultType=""：结果类型，完整写法java.lang.Integer == 使用别名 int（Int）
            order="AFTER"：表示在执行insert语句之后执行
    -->
    <insert id="saveUser" parameterType="com.cpz.domain.User">
      <selectKey keyProperty="id" keyColumn="id" resultType="int" order="AFTER">
          select last_insert_id();
      </selectKey>
        insert into user (username,birthday,sex,address) values (#{username},#{birthday},#{sex},#{address});
    </insert>

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

    <!--删除
        如果传递的是1个参数，通过类型的方式写入值，所以名称随意命名
    -->
    <delete id="deleteUser" parameterType="int">
        delete from user where id = #{id}
    </delete>

    <!--主键查询-->
    <select id="findUserById" parameterType="int" resultType="com.cpz.domain.User">
        select * from user where id = #{id}
    </select>

    <!--模糊查询（方案一）-->
    <select id="findUserByUserNameLike1" resultType="com.cpz.domain.User" parameterType="java.lang.String">
        select * from user where username like #{name}
    </select>

    <!--模糊查询（方案二）-->
    <select id="findUserByUserNameLike2" resultType="com.cpz.domain.User" parameterType="java.lang.String">
        select * from user where username like '%${value}%'
    </select>

    <!--查询数量-->
    <select id="findCount" resultType="int">
        select count(*) from user
    </select>

</mapper>

4.6 log4j.properties 日志配置文件

# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
log4j.rootCategory=debug, CONSOLE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
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

# LOGFILE is set to be a File appender using a PatternLayout.
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

4.7 TestUserDao 测试类

package com.cpz.test;

import com.cpz.dao.UserDao;
import com.cpz.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.IOException;
import java.io.InputStream;
import java.util.Date;
import java.util.List;

public class TestUserDao {
    InputStream is;
    SqlSession sqlSession;
    UserDao userDao;

    @Before
    public void init() throws IOException {
        // 1：加载sqlMapConfig.xml（配置文件），同时加载UserDao.xml（映射文件）
        is = Resources.getResourceAsStream("sqlMapConfig.xml");
        // 2：创建SqlSessionFactory（1个），相当于DataSource
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
        // 3：创建SqlSession（多个，每个线程都会使用独立的SqlSession），相当于Connection
        sqlSession = sqlSessionFactory.openSession();
        // 4：使用SqlSession获取Dao（底层反射和代理技术完成）
        userDao = sqlSession.getMapper(UserDao.class);
    }

    @After
    public void destroy() throws IOException {
        // 手动提交
        sqlSession.commit();
        // 6：关闭资源
        sqlSession.close();
        is.close();
    }

    // 查询所有
    @Test
    public void findAll() throws IOException {
        List<User> list = userDao.findAll();
        for (User user : list) {
            System.out.println(user);
        }
    }

    // 保存
    @Test
    public void saveUser(){
        User user = new User();
        user.setUsername("哪吒");
        user.setSex("男");
        user.setAddress("钱塘关");
        user.setBirthday(new Date());

        System.out.println(user);
        userDao.saveUser(user);
        System.out.println(user);
    }

    // 修改
    @Test
    public void updateUser(){
        User user = new User();
        user.setId(56);
        user.setUsername("浩克");
        user.setSex("男");
        user.setAddress("美国");
        user.setBirthday(new Date());

        userDao.updateUser(user);
    }

    // 删除
    @Test
    public void deleteUser(){
        userDao.deleteUser(56);
    }

    // 主键查询
    @Test
    public void findUserById(){
        User user = userDao.findUserById(52);
        System.out.println(user);
    }

    // 模糊查询（方案一）
    // 如果： select * from user where username like #{abc}，此时%%在条件中完成
    // 此时执行的sql：select * from user where username like ?
    @Test
    public void findUserByUserNameLike1() {
        List<User> list = userDao.findUserByUserNameLike1("%王%");
        for (User user : list) {
            System.out.println(user);
        }
    }

    // 模糊查询（方案二）
    // 如果： select * from user where username like '%${value}%'，此时%%在sql中完成
    // 此时执行的sql：select * from user where username like '%王%'
    // ${value}只能写成value，底层源代码固定value
    @Test
    public void findUserByUserNameLike2(){
        List<User> list = userDao.findUserByUserNameLike2("王");
        for (User user : list) {
            System.out.println(user);
        }
    }

    // 查询数量
    @Test
    public void findCount(){
        int count = userDao.findCount();
        System.out.println(count);
    }
}

4.8 项目结构