mybatis学习（一）不使用 XML 构建 SqlSessionFactory

如果使用 Maven 来构建项目，则需将下面的 dependency 代码置于 pom.xml 文件中：

<dependency>
  <groupId>org.mybatis</groupId>
  <artifactId>mybatis</artifactId>
  <version>x.x.x</version>
</dependency>

配置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>

      <!-- 别名
        .类型别名 typeAlias type属性值为全类名 alias为别名
        .根据包   name属性值为包名 别名为包内类名的小写
      -->
    <typeAliases>
        <!-- <typeAlias type="com.tzh.bean.Clazz" alias="clazz"/>
        <typeAlias type="com.tzh.bean.Student" alias="student"/> -->
        <package name="com.tzh.bean"/>
    </typeAliases>

    <environments default="default">
        <environment id="default">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql:///1606a" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="com/tzh/mapper/*.xml" />
    </mappers>

</configuration>

创建beanSession工厂

每个基于 MyBatis 的应用都是以一个 SqlSessionFactory 的实例为核心的。SqlSessionFactory 的实例可以通过 SqlSessionFactoryBuilder 获得。而 SqlSessionFactoryBuilder 则可以从 XML 配置文件或一个预先定制的 Configuration 的实例构建出 SqlSessionFactory 的实例。

package com.tzh.test;

import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class SqlSessionUtils {

    public static SqlSession getSqlSession() {
        SqlSession sqlSession = null;
        try {
            InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");

            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);

            sqlSession = sqlSessionFactory.openSession();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return sqlSession;
    }

创建mapper接口

package com.tzh.mapper;

import java.util.List;

import com.tzh.bean.Student;

public interface StuMapperDao {

    List<Student> getStuList(Student student);
    List<Student> getStuListChoose(Student student);

    int updateStu(Student student);

    int addStu(List<Student> stuList );

    int delStu(int [] arr);
}

sql语句

<?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 对应的是接口的全名 -->
<mapper namespace="namespace">
     <!-- student为别名 在核心配置文件设置 -->
    <select id="getStuList" resultType="student" parameterType="student">

        select * from 0802_stu
        <!-- where  =  -->
        <!-- 如果内部的判断条件成立，会自动加上where关键字，并且会把多余的and或者or去掉 -->
        <where>
            <if test="sname !=null and sname!='' ">
                and sname like concat('%',#{sname},'%')
            </if>

            <if test="sex!=null and sex!=''">
                and sex =#{sex}
            </if>
            <if test="age >0 ">
                and age &lt; #{age}
            </if>
        </where>
    </select>
    <select id="getStuListChoose" resultType="student"
        parameterType="student">

        select * from 0802_stu
        <!-- where  =  -->
        <!-- 如果内部的判断条件成立，会自动加上where关键字，并且会把多余的and或者or去掉 -->
        <!-- <where> -->
        <trim prefix="where" prefixOverrides="and |or ">
            <!-- 条件成立在前面加上WHER关键词 并 prefixOverrides前缀覆盖 条件成立去挑前缀add|or-->

            <!-- choose when otherwise 用法和switch case break 类似 只运行一个条件都符合时运行第一个 -->
            <choose>
                <when test="sname !=null and sname!='' ">
                    and sname like concat('%',#{sname},'%')
                </when>
                <when test="sex!=null and sex!=''">
                    and sex =#{sex}
                </when>
                <otherwise><!-- 其他相当于else -->
                    and age &lt; #{age}
                </otherwise>
            </choose>
        </trim>
        <!-- </where> -->
    </select>

    <update id="updateStu" parameterType="student">
        update 0802_stu
        <!-- SET 在内部的条件成立，就会加上set关键字，并且会把多余的逗号去掉 -->
        <!-- <set> -->
        <trim prefix="set" suffixOverrides=",">
        <!-- suffixOverrides 去掉多余的 , -->
            <if test="sname != null and sname !=''">
                sname = #{sname},
            </if>
            <if test="sex !=null and sex != ''">
                sex = #{sex},
            </if>
            <if test="age>0">
                age = #{age}
            </if>
            </trim>
        <!-- </set> -->
        where sid= #{sid}
    </update>

    <insert id="addStu" parameterType="list">
        INSERT into 0802_stu (sname,sex,age,cid) VALUES
        <!-- 你可以传递一个 List 实例或者数组作为参数对象传给 MyBatis。
        当你这么做的时 候,MyBatis 会自动将它包装在一个 Map 中,用名称在作为键。
        List 实例将会以“list” 作为键,而数组实例将会以“array”作为键。 -->
        <foreach collection="list" item="stu" separator=",">
            (#{stu.sname},#{stu.sex},#{stu.age},#{stu.cid})
        </foreach>

                <!-- ('隆多','男',,),
                ('隆多','男',,),
                ('隆多','男',,),
                ('隆多','男',,),
                ('隆多','男',,),
                ('隆多','男',,) -->

    </insert>

    <delete id="delStu" parameterType="java.lang.reflect.Array">
        DELETE FROM 0802_stu WHERE sid in
            <foreach collection="array" item="sid" open="("  separator=","  close=")" >
                #{sid}
            </foreach>
    </delete>

</mapper>

测试

package com.tzh.test;

import java.util.ArrayList;
import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import com.tzh.bean.Student;
import com.tzh.mapper.StuMapperDao;

public class TestDemo {

    @Test
    public void testListLike() {

        SqlSession sqlSession = SqlSessionUtils.getSqlSession();
        StuMapperDao mapper = sqlSession.getMapper(StuMapperDao.class);
        Student student = new Student();
        student.setSname("k");
        student.setSex("男");
        student.setAge();

        //List<Student> stuList = mapper.getStuList(student);
        List<Student> stuList = mapper.getStuListChoose(student);
        for (Student student2 : stuList) {
            System.out.println(student2);
        }

    }

    @Test
    public void testUpdate() {

        SqlSession sqlSession = SqlSessionUtils.getSqlSession();
        StuMapperDao mapper = sqlSession.getMapper(StuMapperDao.class);
        Student student = new Student();
        student.setSname("k");
        student.setSex("男");
        //student.setAge(34);
        student.setSid();

        int updateStu = mapper.updateStu(student);
        sqlSession.commit();
    }

    @Test
    public void testAdd() {

        SqlSession sqlSession = SqlSessionUtils.getSqlSession();
        StuMapperDao mapper = sqlSession.getMapper(StuMapperDao.class);
        Student student = new Student();
        student.setSname("k");
        student.setSex("男");
        student.setAge();
        student.setCid();
        Student student1 = new Student();
        student1.setSname("k");
        student1.setSex("男");
        student1.setAge();
        student1.setCid();
        Student student2 = new Student();
        student2.setSname("k");
        student2.setSex("男");
        student2.setAge();
        student2.setCid();

        List<Student> stuList = new ArrayList<Student>();

        stuList.add(student);
        stuList.add(student1);
        stuList.add(student2);

        int addStu = mapper.addStu(stuList);

        sqlSession.commit();

    }

    @Test
    public void testDel() {
        SqlSession sqlSession = SqlSessionUtils.getSqlSession();
        StuMapperDao mapper = sqlSession.getMapper(StuMapperDao.class);

        int [] arr = {,,,,};

        int delStu = mapper.delStu(arr);
        sqlSession.commit();
    }

}