MyBatis框架(二)
2024-10-20 22:55:37
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); } }
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