java框架Mybatis_day01

一、mybatis搭建配置环境
1.导入jar包（坐标）

<?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.itheima</groupId>
    <artifactId>kuangjia001</artifactId>
    <version>1.0-SNAPSHOT</version>
  <dependencies>
      <dependency>
          <groupId>org.mybatis</groupId>
          <artifactId>mybatis</artifactId>
          <version>3.5.0</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>
        <scope>test</scope>
    </dependency>
  </dependencies>

2.创建mybatis主配置文件
D:\黑马培训\ideal代码包\kuangjia001\src\main\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>
    <!--数据库环境：default用于指定默认的配置-->
    <environments default="mysql">
        <environment id="mysql">
            <!--事务管理器：此处配置为JDBC-->
            <transactionManager type="JDBC"></transactionManager>
            <!--配置数据源：type默认先使用POOLED-->
            <dataSource type="POOLED">
            <!--配置数据库链接:目前name的取值要固定-->
            <property name="driver" value="com.mysql.jdbc.Driver"/>
            <property name="url" value="jdbc:mysql///day01"/>
            <property name="username" value="root"/>
            <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!--注册映射文件-->
        <mapper resource="com/itheima/dao/UserMapper.xml"/>
    </mappers>
</configuration>

3.准备实体类和表结构
D:\黑马培训\ideal代码包\kuangjia001\src\main\java\com\itheima\domain\User.java

package com.itheima.domain;
import java.io.Serializable;
import java.util.Date;
public class User implements Serializable {
    private Integer uid;//主键。类型要使用包装类型
    private String name;//登录名
    private String password;//密码
    private String email;//邮箱
    private String phoneNumber;//手机号
    private Date birthday;//生日
    @Override
    public String toString() {
        return "User{" +
                "uid=" + uid +
                ", name='" + name + '\'' +
                ", password='" + password + '\'' +
                ", email='" + email + '\'' +
                ", phoneNumber='" + phoneNumber + '\'' +
                ", birthday=" + birthday +
                '}';
    }
    public Integer getUid() {
        return uid;
    }
    public void setUid(Integer uid) {
        this.uid = uid;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getPhoneNumber() {
        return phoneNumber;
    }
    public void setPhoneNumber(String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
}

4.创建Mapper接口（Dao接口）
D:\黑马培训\ideal代码包\kuangjia001\src\main\java\com\itheima\dao\UserMapper.java


public interface UserMapper {
    /**
     * 添加一条用户记录
     * @param user
     */
    void addUser(User user)
}

5.创建Mapper接口方法和SQL映射文件
D:\黑马培训\ideal代码包\kuangjia001\src\main\resources\mybatis-config.xml（映射文件与src\main\res）

?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属性取值要和Mapper接口类名一致-->
<mapper namespace="com.itheima.dao.UserMapper">
    <!--id取值要和接口中的方法名保持一致
        parameterType:值方法中的参数类型
    -->
    <insert id="addUser" parameterType="com.itheima.domain.User">//parameterType方法中输入值的类型
        INSERT into users (name,password,email,phoneNumber,birthday) values (#{name},#{password},#{email},#{phoneNumber},#{birthday});//#{name}相当于调用users.getname方法
    </insert>
    <!--查询所有用户:封装结果集-->
    <!--映射结果集：数据库字段与实体类属性的对应关系
        id：此映射唯一标识。日后使用
        type：目标类型
    -->
    <resultMap id="userMap" type="com.itheima.domain.User">
        <!--映射主键：column，数据库字段名称，要和查询结果显示的名字保持一致
                property,类中的属性名称。属性指getter（读属性）/setter（写属性）方法，属性名就是去掉get/set，首字母小写的名称
        -->
        <id column="id" property="uid" />
        <result column="username" property="name"/>
        <result column="password" property="password"/>
        <result column="email" property="email"/>
        <result column="phoneNumber" property="phoneNumber"/>
        <result column="birthday" property="birthday"/>
    </resultMap>
    <select id="findAllUsers" resultMap="userMap">
        select uid as id,name username,password,email,phoneNumber,birthday from users
    </select>
    <!--因为列名和属性名保持了一致，可以直接使用resultType指定要封装的目标类型。
        使用前提：遵守约定。简单查询。
    -->
    <select id="findAllUsers1" resultType="com.itheima.domain.User">
        select uid,name,password,email,phoneNumber,birthday from users
    </select>
</mapper>

6。将映射文件添加到Mybatis
D:\黑马培训\ideal代码包\kuangjia001\src\main\resources\mybatis-config.xml

<select id="findAllUsers1" resultType="com.itheima.domain.User">
        select uid,name,password,email,phoneNumber,birthday from users
    </select>

二、入门案例一
1.案例一中主要的类和接口
Resources:加载mybatis配置文件。
SqlSessionFactoryBuilder:利用Resources指定的资源，将配置信息加载到内存中，还会加载所有的配置文件映射配置信息，并用特定的对象实例进行保存，从而创建SqlSessionFactory对象。
SqlSessionFactory:包含所有配置内容的对象，一个项目只用一个。
SqlSession:每个线程独有，用时打开，不用关闭。单独使用mybaits进行开发时最常用的接口。
openSession:获取SqlSessionFactory，返回一个SqlSession对象创建事务。底层是做各种成员变量的初始化。
BasemapperTest基类用于junit单元测试。
classloader:类加载器，将类加载到jvm 中。
Resources 类为从类路径中加载资源，提供了易于使用的方法。
? 从类路径加载 SQL Map 配置文件（如 sqlMap-config.xml）。
? 从类路径加载 DAO Manager 配置文件（如 dao.xml）
? 从类路径加载各种.properties 文件。
2.案例源码
2.1
01.mybatis 的Junit测试基类
1.获取配置文件的输入流
2.通过输入流获得sqlSessionFactoryBuilder工厂
3.创建openSession,获取SqlSessionFactory，返回一个SqlSession对象创建事务。

public class BaseMapperTest {
    private static SqlSessionFactory sqlSessionFactory;
    @BeforeClass//仅在加载类字节码时执行一次
    public static void init(){
        try {
            InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");//获取配置文件的输入流
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
            //SqlSessionFactoryBuilder:加载所有的配置文件映射配置信息，并用特定的对象实例进行保存，从而创建SqlSessionFactory对象。
        } catch (IOException e) {
            e.printStackTrace();
        } 
    }
    protected SqlSession openSession() {return sqlSessionFactory.openSession();}
}

02.测试编码模板


@Test
public void testAddUser3() throws Exception {
    SqlSession sqlSession = null;
    try {
        sqlSession = openSession();
        //获取UserMapper实例
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        System.out.println(userMapper.getClass().getCanonicalName());
        //调用方法
        User user = new User();
        user.setName("user4");
        user.setPassword("sorry");
        user.setEmail("[email protected]");
        user.setPhoneNumber("124");
        user.setBirthday(new Date());
        userMapper.addUser(user);
        //提交事务
        sqlSession.commit();
    }catch (Exception e){
        sqlSession.rollback();
        throw new RuntimeException(e);
    }finally{
        //释放资源
        sqlSession.close();
    }
}

2.2查询所有记录
resultMap映射结果集
com/itheima/dao/UserMapper.xml


<!--查询所有用户:封装结果集-->
<!--映射结果集：数据库字段与实体类属性的对应关系
    id：此映射唯一标识。日后使用
    type：目标类型
-->
<resultMap id="userMap" type="com.itheima.domain.User">
    <!--映射主键：column，数据库字段名称，要和查询结果显示的名字保持一致
            property,类中的属性名称。属性指getter（读属性）/setter（写属性）方法，属性名就是去掉get/set，首字母小写的名称
    -->
    <id column="id" property="uid" />
    <result column="username" property="name"/>
    <result column="password" property="password"/>
    <result column="email" property="email"/>
    <result column="phoneNumber" property="phoneNumber"/>
    <result column="birthday" property="birthday"/>
</resultMap>
//<select id="findAllUsers" resultMap="userMap">  因类名和属性名保持一致，可以用resultType直接指向目标类型。
<select id="findAllUsers" resultType="com.itheima.domain.User">
    select uid as id,name username,password,email,phoneNumber,birthday from users
</select>

com.itheima.test.UserMapperTest

@Test
public void testFinaAllUsers() throws Exception {
    SqlSession sqlSession = null;
    try {
        sqlSession = openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        List<User> users = userMapper.findAllUsers();
        for(User user:users)
            System.out.println(user);
    }catch (Exception e){
        throw new RuntimeException(e);
    }finally{
        sqlSession.close();
    }
}

2.2查询一条记录
com/itheima/dao/UserMapper.xml


<select id="findUserByUid" parameterType="int" resultType="com.itheima.domain.User">
    <!--参数占位符可以随便写。应为参数只有一个，所以名字就不再那么重要了-->
    select uid,name,password,email,phoneNumber,birthday from users where uid=#{uiddddd}
</select>

com.itheima.test.UserMapperTest


@Test
public void testFinaUserByUid() throws Exception {
    SqlSession sqlSession = null;
    try {
        sqlSession = openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = userMapper.findUserByUid(1);
        System.out.println(user);
    }catch (Exception e){
        throw new RuntimeException(e);
    }finally{
        sqlSession.close();
    }
}

2.3查询多条记录
com.itheima.dao.UserMapper

/**

根据用户名和密码查询
@param name,password
@return
*/
User findUserByNamePassword(@Param("name") String name,@Param("password") String password);

//设置param别名，与xml中的代码相联系。

com/itheima/dao/UserMapper.xml

<select id="findUserByNamePassword" resultType="com.itheima.domain.User">
    <!--[arg1, arg0, param1, param2]
    select uid,name,password,email,phoneNumber,birthday from users where name=#{arg0} and password=#{arg1}
    select uid,name,password,email,phoneNumber,birthday from users where name=#{param1} and password=#{param2}
    -->
    select uid,name,password,email,phoneNumber,birthday from users where name=#{name} and password=#{password}
</select>

com.itheima.test.UserMapperTest

@Test
public void testFinaUserByNamePassword() throws Exception {
    SqlSession sqlSession = null;
    try {
        sqlSession = openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = userMapper.findUserByNamePassword("admin","sorry");
        System.out.println(user);
    }catch (Exception e){
        throw new RuntimeException(e);
    }finally{
        sqlSession.close();
    }
}

2.4根据POJO查询
com.itheima.dao.UserMapper

/**
* 根据用户名和密码查询
* @param userVo
* @return
*/
User findUserByNamePassword1(User userVo);
com/itheima/dao/UserMapper.xml

<select id="findUserByNamePassword" parameterType="com.itheima.domain.User" resultType="com.itheima.domain.User">
    select uid,name,password,email,phoneNumber,birthday from users where name=#{name} and password=#{password}
</select>
com.itheima.test.UserMapperTest

@Test
public void testFinaUserByNamePassword1() throws Exception {
    SqlSession sqlSession = null;
    try {
        sqlSession = openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User userVo = new User();
        userVo.setName("admin");
        userVo.setPassword("sorry");
        User user = userMapper.findUserByNamePassword1(userVo);
        System.out.println(user);
    }catch (Exception e){
        throw new RuntimeException(e);
    }finally{
        sqlSession.close();
    }
}

2.5模糊查询
com.itheima.dao.UserMapper

01 List<User> findUsersByName(String name);
02 List<User> findUsersByName1(@Param("name") String name);
03 List<User> findUsersByName2(String name);

com/itheima/dao/UserMapper.xml

01 select uid,name,password,email,phoneNumber,birthday from users where name like #{name}
02 select uid,name,password,email,phoneNumber,birthday from users where name like '%${name}%'
03 select uid,name,password,email,phoneNumber,birthday from users where name like concat('%',#{name},'%')

com.itheima.test.UserMapperTest

01 List<User> users = userMapper.findUsersByName("%user%");
02 List<User> users = userMapper.findUsersByName1("user");
03 List<User> users = userMapper.findUsersByName2("user");

2.6获取自动生成的主键
com.itheima.dao.UserMapper


void addUser1(User user);
void addUser2(User user);

com/itheima/dao/UserMapper.xml


<!--获取数据库自动生成的主键值:仅仅适用于有自动增长能力的数据库，比如mysql、sql server
    useGeneratedKeys:开启获取主键
    keyProperty：获取的主键封装到哪个属性中-->
<insert id="addUser1" parameterType="com.itheima.domain.User" useGeneratedKeys="true" keyProperty="uid">
    INSERT into users (name,password,email,phoneNumber,birthday) values (#{name},#{password},#{email},#{phoneNumber},#{birthday});
</insert>
<!--使用selectKey方式：不仅适用于自动增长的数据库，还适用于非自动增长的数据库-->
<insert id="addUser2" parameterType="com.itheima.domain.User">
    <!--
        keyColumn:指定主键列名
        resultType：生成的主键类型
        keyProperty：封装主键到哪个属性
        order:在数据插入前还是插入后获取主键
    -->
    <selectKey keyColumn="uid" resultType="int" keyProperty="uid" order="AFTER">
        select last_insert_id()
    </selectKey>
    INSERT into users (name,password,email,phoneNumber,birthday) values (#{name},#{password},#{email},#{phoneNumber},#{birthday});
</insert>

com.itheima.test.UserMapperTest

@Test
public void testAddUser6() throws Exception {
    SqlSession sqlSession = null;
    try {
        sqlSession = openSession();
        //获取UserMapper实例
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        System.out.println(userMapper.getClass().getCanonicalName());
        //调用方法
        User user = new User();
        user.setName("user10");
        user.setPassword("sorry");
        user.setEmail("[email protected]");
        user.setPhoneNumber("130");
        user.setBirthday(new Date());
        userMapper.addUser2(user);
        //提交事务
        sqlSession.commit();
        System.out.println(user);
    }catch (Exception e){
        sqlSession.rollback();
        throw new RuntimeException(e);
    }finally{
        //释放资源
        sqlSession.close();
    }
}

2.6修改和删除
com.itheima.dao.UserMapper


void updateUser(User user);
void deleteUserByUid(Integer uid);

com/itheima/dao/UserMapper.xml

<update id="updateUser" parameterType="com.itheima.domain.User">
    update users set name=#{name},password=#{password},email=#{email},phoneNumber=#{phoneNumber},birthday=#{birthday} where uid=#{uid}
</update>
<delete id="deleteUserByUid" parameterType="int">
    delete from users where uid=#{uid}
</delete>

com.itheima.test.UserMapperTest


@Test
public void testDeleteUser() throws Exception {
    SqlSession sqlSession = null;
    try {
        sqlSession = openSession();
        //获取UserMapper实例
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        System.out.println(userMapper.getClass().getCanonicalName());
        userMapper.deleteUserByUid(9);
        sqlSession.commit();
    }catch (Exception e){
        throw new RuntimeException(e);
    }finally{
        sqlSession.close();
    }
}

java框架Mybatis_day01

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