基于ManyToOne的hibernate联合查询，使用JSON查看结果

   本例子中有两个类一个用户类，一个应用类，多个应用对应一个用户。

     应用类

     @Entity
   public class AppManager {
        private String app;
private String appName;
private String appPwd;
private int id;
private UserManager userManager;
@ManyToOne(cascade={CascadeType.ALL})
@JoinColumn(name="username")
public UserManager getUserManager() {
return userManager;
}
public void setUserManager(UserManager userManager) {
this.userManager = userManager;
}
public String getApp() {
return app;
}
public String getAppName() {
return appName;
}
public String getAppPwd() {
return appPwd;
}

@Id
@GeneratedValue
public int getId() {
return id;
       }
  public void setApp(String app) {
this.app = app;
}
       public void setAppName(String appName) {
this.appName = appName;
}
         public void setAppPwd(String appPwd) {
this.appPwd = appPwd;
}
         public void setId(int id) {
this.id = id;
}
       
}

    用户类

    @Entity
public class UserManager {

    @Id
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getUserpwd() {
return userpwd;
}
public void setUserpwd(String userpwd) {
this.userpwd = userpwd;
}
private String username;
private String  userpwd;
}

  测试类

     @Test

public  void  query() {
  
Session session = sif.getCurrentSession();
session.beginTransaction();
Query query= session.createQuery("from AppManager app,UserManager  user where app.userManager = user.username ");
List list =query.list();

session.getTransaction().commit();
JSONArray jsonArray = JSONArray.fromObject(list);
System.out.println(jsonArray.toString());
 Iterator iter = list.iterator();
 while(iter.hasNext()){
 Object[] object = (Object[])iter.next();
 JSONArray jsonArray1 = JSONArray.fromObject(object);
 System.out.println(jsonArray1.toString());
 AppManager a1 =  (AppManager)object[0];
 JSONArray jsonArray2 = JSONArray.fromObject(a1);
 System.out.println(jsonArray2.toString());
          UserManager u1 =  (UserManager)object[1];
 System.out.println(a1.getApp());
 System.out.println(u1.getUsername());
 }

}

     结果为

     Hibernate: 
    select
        appmanager0_.id as id0_0_,                                           //个人猜测:Object[0],Object[1]这里的0和1对应
        usermanage1_.username as username1_1_,
        appmanager0_.app as app0_0_,
        appmanager0_.appName as appName0_0_,
        appmanager0_.appPwd as appPwd0_0_,
        appmanager0_.username as username0_0_,
        usermanage1_.userpwd as userpwd1_1_ 
    from
        AppManager appmanager0_,
        UserManager usermanage1_ 
    where
        appmanager0_.username=usermanage1_.username  // UserManager类转成外键username,引用类型作为外键与基本类型做为的主键能对应上。

     [[{"app":"sina","appName":"123","appPwd":"2123","id":303,"userManager":{"username":"jym","userpwd":""}},{"username":"jym","userpwd":""}]]
     [{"app":"sina","appName":"123","appPwd":"2123","id":303,"userManager":{"username":"jym","userpwd":""}},{"username":"jym","userpwd":""}]
     [{"app":"sina","appName":"123","appPwd":"2123","id":303,"userManager":{"username":"jym","userpwd":""}}]
     sina
     jym

     以JSON的格式输出可以看出，hibernate返回的外键值付给了AppManager类的UserManager引用的username属性。

     在把List链表里的值转成Object数组时不是杂乱无章的，而是按照两个类分别付给了Object。