HibernateLab--多对多

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package org.niit.ormlab.example3;import java.io.Serializable;import java.util.HashSet;import java.util.Set;public class Depart implements Serializable {private Integer did;private String dname;private String ddesc;private Set<Emp> emps = new HashSet<Emp>();//为了提高程序健壮性我们实例化这个属性避免产生空指针异常public Depart(String dname, String ddesc, Set<Emp> emps) {super();this.dname = dname;this.ddesc = ddesc;this.emps = emps;}public Set<Emp> getEmps() {return emps;}public void setEmps(Set<Emp> emps) {this.emps = emps;}public Depart() {}public Depart(String dname, String ddesc) {super();this.dname = dname;this.ddesc = ddesc;}public Depart(Integer did, String dname, String ddesc) {super();this.did = did;this.dname = dname;this.ddesc = ddesc;}public Integer getDid() {return did;}public void setDid(Integer did) {this.did = did;}public String getDname() {return dname;}public void setDname(String dname) {this.dname = dname;}public String getDdesc() {return ddesc;}public void setDdesc(String ddesc) {this.ddesc = ddesc;}}

package org.niit.ormlab.example3;import java.io.Serializable;import java.util.*;public class Emp implements Serializable {private int eid;private String ename;private String esex;private String eaddr;private String etel;private Depart depart;//many to oneprivate Set<Role> roles = new HashSet<Role>();//多对多public Emp() {// TODO Auto-generated constructor stub}public Emp(String ename, String esex, String eaddr, String etel,Depart depart, Set<Role> roles) {super();this.ename = ename;this.esex = esex;this.eaddr = eaddr;this.etel = etel;this.depart = depart;this.roles = roles;}public Set<Role> getRoles() {return roles;}public void setRoles(Set<Role> roles) {this.roles = roles;}public Emp(int eid, String ename, String esex, String eaddr, String etel,Depart depart, Set<Role> roles) {super();this.eid = eid;this.ename = ename;this.esex = esex;this.eaddr = eaddr;this.etel = etel;this.depart = depart;this.roles = roles;}public Emp(String ename, String esex, String eaddr, String etel,Depart depart) {super();this.ename = ename;this.esex = esex;this.eaddr = eaddr;this.etel = etel;this.depart = depart;}public Emp(int eid, String ename, String esex, String eaddr, String etel,Depart depart) {super();this.eid = eid;this.ename = ename;this.esex = esex;this.eaddr = eaddr;this.etel = etel;this.depart = depart;}public int getEid() {return eid;}public void setEid(int eid) {this.eid = eid;}public String getEname() {return ename;}public void setEname(String ename) {this.ename = ename;}public String getEsex() {return esex;}public void setEsex(String esex) {this.esex = esex;}public String getEaddr() {return eaddr;}public void setEaddr(String eaddr) {this.eaddr = eaddr;}public String getEtel() {return etel;}public void setEtel(String etel) {this.etel = etel;}public Depart getDepart() {return depart;}public void setDepart(Depart depart) {this.depart = depart;}}

package org.niit.ormlab.example3;import java.io.Serializable;import java.util.*;public class Role implements Serializable {private int rid;private String rname;private String rdesc;private Set<Emp> emps = new HashSet<Emp>();//many to manypublic Role(String rname, String rdesc) {super();this.rname = rname;this.rdesc = rdesc;}public Role(String rname, String rdesc, Set<Emp> emps) {super();this.rname = rname;this.rdesc = rdesc;this.emps = emps;}public Role() {super();}public Role(int rid, String rname, String rdesc, Set<Emp> emps) {super();this.rid = rid;this.rname = rname;this.rdesc = rdesc;this.emps = emps;}public int getRid() {return rid;}public void setRid(int rid) {this.rid = rid;}public String getRname() {return rname;}public void setRname(String rname) {this.rname = rname;}public String getRdesc() {return rdesc;}public void setRdesc(String rdesc) {this.rdesc = rdesc;}public Set<Emp> getEmps() {return emps;}public void setEmps(Set<Emp> emps) {this.emps = emps;}}

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" ><hibernate-mapping package="org.niit.ormlab.example3"><class name="Emp" table="`Emp`"><id name="eid" column="eid" type="integer"><generator class="identity" /></id><property name="ename" column="ename" type="string" /><property name="esex" column="esex" type="string" /><property name="etel" column="`etel`" type="string"/><property name="eaddr" column="eaddr" type="string" /><many-to-onename="depart" class="Depart" column="did"cascade="save-update"not-null="true"/><set name="roles" cascade="save-update" table="`roleemp`" lazy="true" inverse="true" ><key column="eid" not-null="true"></key><many-to-many class="Role" column="rid"/></set></class></hibernate-mapping>

测试代码:

package org.niit.ormlab.example3;import java.util.List;import org.hibernate.Session;import org.hibernate.Transaction;import org.hibernate.criterion.Restrictions;public class Client {/**保存角色和员工使用级联*/public void saveRoleAndEmpWithCascade(){Session session = SessionFactory.getSession();Transaction ts = session.beginTransaction();try {Depart depart = (Depart)session.get(Depart.class,19);Role r = new Role("市场经理","市场经理");Emp e1 = new Emp("王涛", "男", "成都市武侯区", "115", depart);Emp e2 = new Emp("王丽", "女", "成都市武侯区", "116", depart);//建立角色对象和员工对象的双向关系r.getEmps().add(e1);r.getEmps().add(e2);//e1.getRoles().add(r);//在Role的映射上使用了cascade=save-update可以省略这一句代码//e2.getRoles().add(r);//在Role的映射上使用了cascade=save-update可以省略这一句代码session.save(r);//保存角色对象ts.commit();} catch (Exception e) {e.printStackTrace();ts.rollback();} finally {session.close();}}/** * 得到角色信息及该角色的员工信息 * */public void getRoleAndEmps(){Session session = SessionFactory.getSession();try {Role r = (Role)session.createQuery("from Role as r where r.rid=?").setParameter(0, 3).uniqueResult();System.out.println(r.getRid()+"/t"+r.getRname());for (Emp e : r.getEmps()) {System.out.println("/t"+e.getEid()+"/t"+e.getEname());}} catch (Exception e) {e.printStackTrace();} finally {session.close();}}public static void main(String[] args) {Client c = new Client();//c.saveRoleAndEmpWithCascade();c.getRoleAndEmps();}}