一、两种方式初始化Mybatis

一、xml

Configuration.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>
     <!-- 用于建立会话的变量，可以从文件中读取 -->
     <properties resource="config/config.properties">
         <property name="driver" value="com.mysql.jdbc.Driver" />
         <property name="url" value="jdbc:mysql://localhost:3306/test" />
         <property name="username" value="root" />
         <property name="password" value="asd123" />
     </properties>

     <!-- 可以不设置 -->
     <!-- <setting></setting> -->

     <typeAliases>
         <typeAlias alias="Student" type="entity.Student"></typeAlias>
         <typeAlias alias="Score" type="entity.Score"></typeAlias>
     </typeAliases>
     <environments default="development">
         <environment id="development">
             <transactionManager type="JDBC" />
             <dataSource type="POOLED">
                 <property name="driver" value="${driver}" />
                 <property name="url" value="${url}" />
                 <property name="username" value="${username}" />
                 <property name="password" value="${password}" />
             </dataSource>
         </environment>
     </environments>
     <mappers>
         <mapper resource="mapper/StudentMapper.xml" />
         <mapper resource="entity/ScoreMapper.xml" />
     </mappers>
 </configuration> 

StudentMapper.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="mapper.StudentMapper">

     <resultMap type="Student" id="StudentResultMap">
         <id property="id" column="id" />
         <result property="name" column="name" />
         <result property="password" column="password" />
         <result property="sex" column="sex" />
         <result property="college" column="college" />
         <collection property="scores" column="sid" javaType="ArrayList" ofType="Score" resultMap="Score.ScoreResultMap" />
     </resultMap>

     <select id="get" parameterType="String" resultMap="StudentResultMap">
         SELECT * FROM sc_student st LEFT OUTER JOIN sc_score sc ON st.id=sc.sid WHERE st.id=#{id}
     </select>
     <insert id="insert" parameterType="Student">
         insert into sc_student (id,name,password,sex,college) values
         (#{id},#{name},#{password},#{sex},#{college})
     </insert>
     <update id="update" parameterType="Student">
         UPDATE sc_student SET id=#{id},name=#{name},password=#{password},
         sex=#{sex},college=#{college} WHERE id=#{id}
     </update>
     <delete id="delete" parameterType="Student">
         DELETE FROM sc_student WHERE id = #{id}
     </delete>
 </mapper>

 package test;

 import java.io.IOException;
 import java.io.Reader;

 import mapper.StudentMapper;

 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.Before;
 import org.junit.BeforeClass;
 import org.junit.Test;

 import entity.Student;

 public class TestXmlBuild1 {
     public static SqlSessionFactory sqlMapper = null;

     @Before
     public void setUpClass() throws IOException {
         String resource = "config/Configuration1.xml";
         Reader reader = Resources.getResourceAsReader(resource);
         sqlMapper = new SqlSessionFactoryBuilder().build(reader);
     }

     @Test
     public void test1() {
         SqlSession session = sqlMapper.openSession();
         //第一种方法，直接调用，名字要和<mapper namespace="mapper.StudentMapper">匹配
         try {
             Student student = (Student) session.selectOne("mapper.StudentMapper.get", "ttt");
             System.out.println(student);
         } finally {
             session.close();
         }
     }

     @Test
     public void test2() {
         SqlSession session = sqlMapper.openSession();
         //第二种方法，通过接口，mapper名字需要和<mapper namespace="mapper.StudentMapper">匹配
         try {
             StudentMapper studentMapper = session.getMapper(StudentMapper.class);
             Student student = studentMapper.get("ttt123");
             System.out.println(student);
         } finally {
             session.close();
         }
     }
 }

二、不使用XML构建SqlSessionFactory

没用到，就不解释了。

 DataSource dataSource = BlogDataSourceFactory.getBlogDataSource();
 TransactionFactory transactionFactory = new
 JdbcTransactionFactory();
 Environment environment =
 new Environment("development", transactionFactory, dataSource);
 Configuration configuration = new Configuration(environment);
 configuration.addMapper(BlogMapper.class);
 SqlSessionFactory sqlSessionFactory =
 new SqlSessionFactoryBuilder().build(configuration);