一、两种方式初始化Mybatis

<?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>

<?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();
}
}
}

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);