Java开源技术专业语言:HibernateHQL查询2
时间:2014-04-29
来源:Java认证考试网 浏览次数:361
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7.修改默认查询结果(query.list())不以Object[]数组形式返回,以自定义类型返回 自定义类: Java代码 package co
自定义类:
Java代码
package com.domain;
public class MyUser {
private String username;
private String password;
//因为:String hql = " select new com.domain.MyUser(name,passwd) from Users";所以必须要有接受2个参数的构造函数
public MyUser(String username,String password){
this.username = username;
this.password = password;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
Java代码
//通过query.list()出来的list里存放的不再是默认的Object数组了,而是自定义的类MyUser,必须加包名,String hql = "from Users";中的Users类也是必须加包名的,但是因为再Users.hbm.xml里<hibernate-mapping auto-import="true"> auto-import默认值为true(所以auto-import属性也可以不写),自动导入了
String hql = " select new com.domain.MyUser(name,passwd) from Users";
Query query = session.createQuery(hql);
//默认查询出来的list里存放的是一个Object数组,但是在这里list里存放的不再是默认的Object数组了,而是MyUser对象了
List<MyUser> myUsers = query.list();
for(MyUser myUser : myUsers){
String name = myUser.getUsername();
String passwd = myUser.getPassword();
System.out.println(name + " : " + passwd);
}
/**
输出结果为:
name1 : password1
name2 : password2
name3 : password3
*/
8:条件查询
Java代码
//条件查询,参数索引值从0开始,索引位置。通过setString,setParameter设置参数
String hql = "from Users where name=? and passwd=?";
Query query = session.createQuery(hql);
//第1种方式
// query.setString(0, "name1");
// query.setString(1, "password1");
//第2种方式
query.setParameter(0, "name1",Hibernate.STRING);
query.setParameter(1, "password1",Hibernate.STRING);
List<Users> list = query.list();
for(Users users : list){
System.out.println(users.getId());
}
Java代码
//条件查询,自定义索引名(参数名):username,:password.通过setString,setParameter设置参数
String hql = "from Users where name=:username and passwd=:password";
Query query = session.createQuery(hql);
//第1种方式
// query.setString("username", "name1");
// query.setString("password", "password1");
//第2种方式,第3个参数确定类型
query.setParameter("username", "name1",Hibernate.STRING);
query.setParameter("password", "password1",Hibernate.STRING);
List<Users> list = query.list();
for(Users users : list){
System.out.println(users.getId());
}
Java代码
//条件查询,通过setProperties设置参数
String hql = "from Users where name=:username and passwd=:password";
Query query = session.createQuery(hql);
//MyUser类的2个属性必须和:username和:password对应
MyUser myUser = new MyUser("name1","password1");
query.setProperties(myUser);
List<Users> list = query.list();
for(Users users : list){
System.out.println(users.getId());
}
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