MyBatis框架（二）

导包，

配置mybatis的总配置文件: 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>
     <!-- 引入数据库的信息的属性文件 -->
     <properties resource="db.properties"></properties>
 
     <typeAliases>
         <package name="model"/>
     </typeAliases>
 
     <environments default="hanqi">
         <environment id="hanqi">
             <!--
                 JDBC:
                 MANAGED:托管
              -->
             <transactionManager type="JDBC" />
             <!--
                 配置数据库源
                 POOLED: 连接池
                 UNPOOLED: 非连接池
                 JNDI: 使用应用服务器上的数据库连接
              -->
             <dataSource type="POOLED">
                 <property name="username" value="${jdbc.username}"/>
                 <property name="password" value="${jdbc.password}"/>
                 <property name="url" value="${jdbc.url}"/>
                 <property name="driver" value="${jdbc.driver}"/>
             </dataSource>
         </environment>
 
     </environments>
 
     <mappers>
         <!--
         <mapper resource="mapper/StudentMapper.xml" />
         <mapper class=""></mapper>
         <mapper url="f:/test/StudentMapper.xml"></mapper>
          -->
         <!--
         如果有多个，用包名，自动在包下面搜索
          -->
         <package name="com.hanqi.maya.mapper" />
     </mappers>
 
 </configuration>

新建每个实体类的接口和映射文件，并在xml映射文件中引入接口

 package mapper;
 
 import java.util.List;
 import java.util.Map;
 
 import model.Student;
 
 public interface StudentMapper {
     public List<Student> selectAllStudent();
 
     public int insertStudent(Student s);
 
     public int updateStudent(Map m);
 
     public int deleteStudent(Map m);
 
 }

 <?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">
 
     <select id="selectAllStudent" resultType="Student">
         select * from student
     </select>
 
     <insert id="insertStudent" parameterType="Student" useGeneratedKeys="true" keyProperty="sno" keyColumn="SNO">
         insert into student values(test1.nextval, #{name}, #{sex}, #{sbirthday}, #{sclass})
     </insert>
 
     <update id="updateStudent" parameterType="Map">
         update student s set s.sname=#{stuname},s.sbirthday=#{newDate}
         where s.sno=#{stusno}
     </update>
 
     <delete id="deleteStudent" parameterType="Map">
         delete student s where s.sno=#{stusno}
     </delete>
 
 </mapper>

namespace中如果是ID，可以随便写，需要唯一，如果是引入接口，需要接口和本文件名一致。

测试：

 package test;
 
 import static org.junit.Assert.*;
 
 import java.util.Date;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
 import org.apache.ibatis.session.SqlSession;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import mapper.StudentMapper;
 import model.Student;
 import util.MyBatisUtil;
 
 public class JUTest {
 
     private SqlSession ss;
     //定义接口类，拿到接口
     private StudentMapper sm;
 
     @Before
     public void setUp() throws Exception {
         ss=MyBatisUtil.getSession();
         sm=ss.getMapper(StudentMapper.class);
     } 
 
     @After
     public void tearDown() throws Exception {
         MyBatisUtil.destory(ss);
     }
 
     @Test
     public void test() {
         List<Student> slist=sm.selectAllStudent();
 
         /*Student s=new Student(null,"name","sex",new Date(),95053);
         int a=sm.insertStudent(s);
         System.out.println(a);*/
 
         /*Map m=new HashMap();
         m.put("stusno", "101");
         m.put("stuname", "修改1");
         m.put("newDate",new Date());
         int a=sm.updateStudent(m);
         System.out.println(a);*/
 
         Map m1=new HashMap();
         m1.put("stusno", "s");
         int b=sm.deleteStudent(m1);
 
         for(Student s:slist){
             System.out.println(s);
         }
 
     }
 
 }

关联查询：

一对一查询（三种方式），

一对多查询

部门表P_Dept和员工表P_Emp

员工表中有部门编号

员工类中有部门属性

部门类中有员工集合属性

通过联合查询，查询员工时得到员工属性和部门，查询部门时通过联合查询得出员工列表

结构：

model包：

 packa1ge model;
 
 import java.util.Date;
 
 public class Emp {
     private int empno;
     private String ename;
     private String job;
     private int mgr;
     private Date hiredate;
     private int sal;
     private int comm;
     private int deptno;
     private int sex;
     private Dept dept;
     public Emp() {
         super();
         // TODO Auto-generated constructor stub
     }
     public Emp(int empno, String ename, String job, int mgr, Date hiredate, int sal, int comm, int deptno, int sex,
             Dept dept) {
         super();
         this.empno = empno;
         this.ename = ename;
         this.job = job;
         this.mgr = mgr;
         this.hiredate = hiredate;
         this.sal = sal;
         this.comm = comm;
         this.deptno = deptno;
         this.sex = sex;
         this.dept = dept;
     }
     public int getEmpno() {
         return empno;
     }
     public void setEmpno(int empno) {
         this.empno = empno;
     }
     public String getEname() {
         return ename;
     }
     public void setEname(String ename) {
         this.ename = ename;
     }
     public String getJob() {
         return job;
     }
     public void setJob(String job) {
         this.job = job;
     }
     public int getMgr() {
         return mgr;
     }
     public void setMgr(int mgr) {
         this.mgr = mgr;
     }
     public Date getHiredate() {
         return hiredate;
     }
     public void setHiredate(Date hiredate) {
         this.hiredate = hiredate;
     }
     public int getSal() {
         return sal;
     }
     public void setSal(int sal) {
         this.sal = sal;
     }
     public int getComm() {
         return comm;
     }
     public void setComm(int comm) {
         this.comm = comm;
     }
     public int getDeptno() {
         return deptno;
     }
     public void setDeptno(int deptno) {
         this.deptno = deptno;
     }
     public int getSex() {
         return sex;
     }
     public void setSex(int sex) {
         this.sex = sex;
     }
     public Dept getDept() {
         return dept;
     }
     public void setDept(Dept dept) {
         this.dept = dept;
     }
     @Override
     public String toString() {
         return "Emp [empno=" + empno + ", ename=" + ename + ", job=" + job + ", mgr=" + mgr + ", hiredate=" + hiredate
                 + ", sal=" + sal + ", comm=" + comm + ", deptno=" + deptno + ", sex=" + sex + ", dept=" + dept + "]";
     }
 
 }

 package model;
 
 import java.util.List;
 
 public class Dept {
     private int deptno;
     private String dname;
     private String loc;
     private List<Emp> elist;
     public Dept() {
         super();
         // TODO Auto-generated constructor stub
     }
     public Dept(int deptno, String dname, String loc) {
         super();
         this.deptno = deptno;
         this.dname = dname;
         this.loc = loc;
     }
 
     public Dept(int deptno, String dname, String loc, List<Emp> elist) {
         super();
         this.deptno = deptno;
         this.dname = dname;
         this.loc = loc;
         this.elist = elist;
     }
 
     public List<Emp> getElist() {
         return elist;
     }
     public void setElist(List<Emp> elist) {
         this.elist = elist;
     }
     public int getDeptno() {
         return deptno;
     }
     public void setDeptno(int deptno) {
         this.deptno = deptno;
     }
     public String getDname() {
         return dname;
     }
     public void setDname(String dname) {
         this.dname = dname;
     }
     public String getLoc() {
         return loc;
     }
     public void setLoc(String loc) {
         this.loc = loc;
     }
     @Override
     public String toString() {
         return "Dept [deptno=" + deptno + ", dname=" + dname + ", loc=" + loc + ", elist=" + elist + "]";
     }
 
 }

mapper包：

 package mapper;
 
 import java.util.List;
 
 import model.Dept;
 import model.Emp;
 
 public interface DeptMapper {
     Dept selectDeptByDeptno(Integer id);
 }

 <?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.DeptMapper">
 
     <resultMap type="Dept" id="abc">
         <collection property="elist" column="deptno"
             select="mapper.EmpMapper.selectEmpByDeptno" />
     </resultMap>
 
     <select id="selectDeptByDeptno" parameterType="Integer" resultMap="abc">
         select * from p_dept d where d.deptno=#{deptno}
     </select>
 
 </mapper>

 package mapper;
 
 import java.util.List;
 
 import model.Emp;
 
 public interface EmpMapper {
     //查询所有信息
     List<Emp> selectAllEmp();
     // 根据部门id查询员工
     List<Emp> selectEmpByDeptno(Integer deptno);
 }

 <?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.EmpMapper">
 
     <!-- 对象及联 -->
     <resultMap type="Emp" id="empList">
         <id property="empno" column="empno" />
         <result property="ename" column="ename" />
         <result property="job" column="job" />
         <result property="mgr" column="mgr" />
         <result property="hiredate" column="hiredate" />
         <result property="sal" column="sal" />
         <result property="comm" column="comm" />
         <result property="deptno" column="deptno" />
         <result property="sex" column="sex"/>
         <result property="dept.deptno" column="deptno"/>
         <result property="dept.dname" column="dname"/>
         <result property="dept.loc" column="loc"/>
     </resultMap>
 
     <select id="selectAllEmp" resultMap="empList">
         select * from p_Emp e left join p_Dept d  on d.deptno=e.deptno
 
     </select>
 
     <!-- 关联 -->
     <!-- <resultMap type="Emp" id="empList1">
         <id property="empno" column="empno" />
         <result property="ename" column="ename" />
         <result property="job" column="job" />
         <result property="mgr" column="mgr" />
         <result property="hiredate" column="hiredate" />
         <result property="sal" column="sal" />
         <result property="comm" column="comm" />
         <result property="deptno" column="deptno" />
         <result property="sex" column="sex"/>
         <association property="dept" resultMap="deptlist"></association>
     </resultMap>
     <resultMap type="Dept" id="deptlist">
         <result property="deptno" column="deptno"/>
         <result property="dname" column="dname"/>
         <result property="loc" column="loc"/>
     </resultMap>
 
     <select id="selectAllEmp" resultMap="empList1">
         select * from p_Emp e left join p_Dept d  on d.deptno=e.deptno
     </select> -->
     <!-- 关联查询 -->
 <!--     <resultMap type="Emp" id="empList3">
         <association property="dept" column="deptno"
             select="mapper.DeptMapper.selectDeptById" />
     </resultMap>
 
     <select id="selectAllEmp" resultMap="empList3">
         select * from p_EMP t
     </select> -->
     <!-- 一对多 -->
     <select id="selectEmpByDeptno" parameterType="Integer" resultType="Emp">
         SELECT * FROM p_emp e WHERE e.deptno=#{deptno}
     </select>
 
 </mapper>

测试：

 package test;
 
 import static org.junit.Assert.*;
 
 import java.util.List;
 
 import org.apache.ibatis.session.SqlSession;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 
 import mapper.DeptMapper;
 import mapper.EmpMapper;
 import model.Dept;
 import model.Emp;
 import util.MyBatisUtil;
 
 public class JUTest {
     private SqlSession ss;
     private EmpMapper em;
     private DeptMapper dm;
 
     @Before
     public void setUp() throws Exception {
         ss = MyBatisUtil.getSession();
         em = ss.getMapper(EmpMapper.class);
         dm = ss.getMapper(DeptMapper.class);
     }
 
     @After
     public void tearDown() throws Exception {
         MyBatisUtil.destory(ss);
     }
 
     @Test
     public void test() {
         /*List<Emp> slist=em.selectAllEmp();
         for(Emp e:slist){
             System.out.println(e);
         }*/
 
         /*List<Emp> elist = em.selectEmpByDeptno(10);
         System.out.println(elist);*/
 
         Dept d = dm.selectDeptByDeptno(10);
         System.out.println(d);
     }
 
 }