MyBatis配置

 mybatis-config.xml配置

<?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>
    <settings>     
    	<!-- 允许JDBC支持生成的键 自动增长-->
        <setting name="useGeneratedKeys" value="true"/>
    </settings>  
	<typeAliases>
		<!-- 配置数据类型的别名 -->
		<typeAlias type="com.luohao.entity.Classes"  alias="Classes"/>
		<typeAlias type="com.luohao.entity.Student"  alias="Student"/>
	</typeAliases>
	<!-- 默认的环境ID  -->
	<environments default="development">
		<!-- 每个environment元素定义的环境ID -->
		<environment id="development">
			<!-- 事务处理方式 -->
			<transactionManager type="JDBC" />
			<!-- 数据源配置 -->
			<dataSource type="POOLED">
				<!-- 数据库JDBC驱动 -->
				<property name="driver" value="com.mysql.jdbc.Driver" />
				<!-- 数据库URL -->
				<property name="url" value="jdbc:mysql://localhost:3306/school" />
				<!-- 数据库用户 -->
				<property name="username" value="root" /> 
				<!-- 密码 -->
				<property name="password" value="950126" />
			</dataSource>
		</environment>
	</environments>
	<mappers>
		<!-- 配置映射文件 -->
		<mapper resource="com/luohao/mapper/ClassesMapper.xml"/>
		<mapper resource="com/luohao/mapper/StudentMapper.xml"/>
	</mappers>
</configuration>

---

MyBatisUtils中的sqlsessionFactroy

package com.luohao.util;
 
import java.io.IOException;
import java.io.Reader;
 
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 
public class MyBatisUtil { //获取SqlSession工具类
	//单例SqlSessionFactory对象
	private MyBatisUtil(){}
	private final static SqlSessionFactory sqlSessionFactory; 
	static{ //静态语句块，仅执行一次
		String resource = "mybatis-config.xml"; 
		Reader reader = null;
		try {
		     reader = Resources.getResourceAsReader(resource); //读取配置文件		
		} catch (IOException e) {
		     System.out.println(e.getMessage());
		}
 
		//创建SqlSessionFactory对象
		sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);  
	}
	//返回单例SqlSessionFactory对象
	public static SqlSessionFactory getSqlSessionFactory(){
		return sqlSessionFactory;
	}
}

studentMapper.java

 
import java.util.HashMap;
import java.util.List;
 
import com.luohao.entity.Student;
 
public interface StudentMapper {
	
	public void insert(Student student);
	
	public void delete(int stuId);
	
	public void update(Student student);
 
	public Student getStudentById(int stuId);
	
	public List<Student> getStudents();
	
	public List<Student> getStudentsPage(HashMap<String, Integer> map);
	
	/**
	 * 动态sql查询
	 * @param student
	 * @return
	 */
	public List<Student> searchStudent(Student student);
}

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">
	<!-- 映射器名字空间，即BlogMapper对象的完整路径名 -->
<mapper namespace="com.luohao.mapper.StudentMapper">
	<resultMap type="Student" id="studentResult">
		<id column="stuId" property="stuId" />
		<result column="name" property="name" />
		<result column="age" property="age" />
		<result column="sex" property="sex" />
		<association column="classId" property="classes" javaType="Classes">
			<id column="classId" property="classId"/>
			<id column="cname" property="name"/>
		</association>
	</resultMap>
	
	<insert id="insert" parameterType="Student">
		insert into student(name,age,sex,classId) values (#{name},#{age},#{sex},#{classes.classId})
	</insert>
	
	<delete id="delete" parameterType="int">
		delete from student where stuId = #{0}
	</delete>
	
	<update id="update" parameterType="Student">
		update student set name = #{name},age = #{age},sex = #{sex},classId = #{classes.classId} where stuId = #{stuId}
	</update>
	
	<select id="getStudentById" parameterType="int" resultMap="studentResult">
    	SELECT s.*,c.classId,c.name from student s INNER JOIN classes c on s.classId = c.classId where s.stuId = #{0};
    </select>
	
    <select id="getStudents"  resultMap="studentResult">
    	SELECT s.*,c.classId,c.name as cname from student s INNER JOIN classes c on s.classId = c.classId;
    </select>
    
    <select id="getStudentsPage" parameterType="HashMap" resultMap="studentResult">
    	SELECT * from student LIMIT ${start},${end};
    </select>
    
    <select id="searchStudent" parameterType="Student" resultMap="studentResult">
    	SELECT * from student 
    	<where>
    		<if test="name!=null">
    			and name like #{name}
    		</if>
    		<if test="age!=null">
    			and age = ${age}
    		</if>
    		<if test="sex!=null">
    			and sex = ${sex}
    		</if>
    	</where>
    	
    </select>
	
</mapper>

studentService.java

package com.luohao.service;
 
import java.util.HashMap;
import java.util.List;
 
import org.apache.ibatis.session.SqlSession;
 
import com.luohao.entity.Classes;
import com.luohao.entity.Student;
import com.luohao.mapper.ClassesMapper;
import com.luohao.mapper.StudentMapper;
import com.luohao.util.MyBatisUtil;
 
public class StudentService {
	
	public List<Student> getStudents(){
		SqlSession session = MyBatisUtil.getSqlSessionFactory().openSession();
		StudentMapper mapper = session.getMapper(StudentMapper.class);
		return mapper.getStudents();
	}
	
	public Student getStudentById(int stuId){
		SqlSession session = MyBatisUtil.getSqlSessionFactory().openSession();
		StudentMapper mapper = session.getMapper(StudentMapper.class);
		return mapper.getStudentById(stuId);
	}
	
	public List<Student> getStudentsPage(int pageIndex,int pageSize){
		SqlSession session = MyBatisUtil.getSqlSessionFactory().openSession();
		StudentMapper mapper = session.getMapper(StudentMapper.class);
		HashMap<String, Integer> map = new HashMap<String, Integer>();
		map.put("start", (pageIndex-1)*pageSize);
		map.put("end", pageSize);
		return mapper.getStudentsPage(map);
	}
	
	public void insert(Student student){
		SqlSession session = MyBatisUtil.getSqlSessionFactory().openSession();
		StudentMapper mapper = session.getMapper(StudentMapper.class);
		mapper.insert(student);
		session.commit();
		session.close();
	}
	
	public void delete(int stuId){
		SqlSession session = MyBatisUtil.getSqlSessionFactory().openSession();
		StudentMapper mapper = session.getMapper(StudentMapper.class);
		mapper.delete(stuId);
		session.commit();
		session.close();
	}
	
	public void update(Student student){
		SqlSession session = MyBatisUtil.getSqlSessionFactory().openSession();
		StudentMapper mapper = session.getMapper(StudentMapper.class);
		mapper.update(student);
		session.commit();
		session.close();
	}
	
	public List<Student> searchStudent(Student student){
		SqlSession session = MyBatisUtil.getSqlSessionFactory().openSession();
		StudentMapper mapper = session.getMapper(StudentMapper.class);
		return mapper.searchStudent(student);
	}
}