22_4mybatis——动态SQL

1.创建maven工程并导入坐标

<?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的主配置文件 -->
<configuration>
    <!-- 配置环境 -->
    <environments default="mysql">
        <!-- 配置mysql环境 -->
        <environment id="mysql">
            <!-- 事物类型 -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- 配置数据源（连接池） -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/eesy_mybatis" />
                <property name="username" value="root" />
                <property name="password" value="123456" />
            </dataSource>
        </environment>
    </environments>
    <!-- 指定映射配置文件的位置，映射配置文件指的是dao独立的配置文件-->
    <mappers>
        <mapper resource="com/itheima/dao/IUserDao.xml"/>
    </mappers>
</configuration>

2.创建实体类和dao的接口

package com.itheima.domain;

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

public class User implements Serializable {
    private Integer id;
    private String username;
    private Date birthday;
    private String sex;
    private String 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 Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date 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;
    }

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

package com.itheima.domain;

import java.util.List;

/**
 * @author 黑马程序员
 * @Company http://www.ithiema.com
 */
public class QueryVo {

    private User user;

    private List<Integer> ids;

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public List<Integer> getIds() {
        return ids;
    }

    public void setIds(List<Integer> ids) {
        this.ids = ids;
    }
}

package com.itheima.dao;

import com.itheima.domain.QueryVo;
import com.itheima.domain.User;

import java.util.List;

public interface IUserDao {

    List<User> findAll();

    List<User> findByCondition(User user);

    List<User> findInIds(QueryVo vo);
}

3.创建Mybatis的主配置文件

<?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的主配置文件 -->
<configuration>
    <!-- 配置环境 -->
    <environments default="mysql">
        <!-- 配置mysql环境 -->
        <environment id="mysql">
            <!-- 事物类型 -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- 配置数据源（连接池） -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/eesy_mybatis" />
                <property name="username" value="root" />
                <property name="password" value="123456" />
            </dataSource>
        </environment>
    </environments>
    <!-- 指定映射配置文件的位置，映射配置文件指的是dao独立的配置文件-->
    <mappers>
        <mapper resource="com/itheima/dao/IUserDao.xml"/>
    </mappers>
</configuration>

4.创建映射配置文件

<?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">
<mapper namespace="com.itheima.dao.IUserDao">

    <!-- 配置查询所有 -->
    <select id="findAll" resultType="com.itheima.domain.User">
        select  *  from  user;
    </select>

    <select id="findByCondition" resultType="com.itheima.domain.User">
        <!-- select * from user where 1=1
         <if test="username!= null">
             and username = #{username}
         </if>
         <if test="sex!=null">
             and sex = #{sex}
         </if>-->
        -- 不写where1=1
         select * from user
         <where>
             <if test="username!= null">
                 and username = #{username}
             </if>
             <if test="sex!=null">
                 and sex = #{sex}
             </if>
         </where>

    </select>

    <select id="findInIds" resultType="com.itheima.domain.User" parameterType="com.itheima.domain.QueryVo">
        <!--<include refid="defaultUser"></include>-->
        select * from user
        <where>
            <if test="ids != null and ids.size()>0">
                <foreach collection="ids" open="and id in (" close=")" item="id" separator=",">
                    #{id}
                </foreach>
            </if>
        </where>
    </select>
</mapper>

5.测试程序

package com.itheima.test;

import com.itheima.dao.IUserDao;
import com.itheima.domain.QueryVo;
import com.itheima.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.ArrayList;
import java.util.Date;
import java.util.List;

public class MybatisTest {
    private InputStream in;
    private SqlSession sqlSession;
    private IUserDao userDao;

    @Before
    public void init() throws IOException {
        // 1.读取文件
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        // 2.创建SqlSessionFactory工厂
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        // 3.使用工厂生产SQLSession对象
        sqlSession = factory.openSession(true);
        // 4.使用SQLSession创建Dao接口的代理对象
        userDao = sqlSession.getMapper(IUserDao.class);
    }

    @After
    public void destroy() throws IOException {
        // 提交事务
//        sqlSession.commit();
        // 关闭资源
        sqlSession.close();
        in.close();
    }

    /**
     * 查询所有用户
     */
    @Test
    public void findAll() throws IOException {

        List<User> users = userDao.findAll();
        for (User user : users) {
            System.out.println(user);
        }
    }

    /**
     * 测试查询所有
     */
    @Test
    public void testFindByCondition() {
        User u = new User();
        u.setUsername("老王");
//        u.setSex("女");

        //5.执行查询所有方法
        List<User> users = userDao.findByCondition(u);
        for (User user : users) {
            System.out.println(user);
        }

    }
    /**
     * 测试查询所有
     */
    @Test
    public void testFindInIds() {
        QueryVo qo = new QueryVo();
        List<Integer> list = new ArrayList<Integer>();
        list.add(41);
        list.add(42);
        list.add(46);
        qo.setIds(list);

        //5.执行查询所有方法
        List<User> users = userDao.findInIds(qo);
        for (User user : users) {
            System.out.println(user);
        }

    }

}