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<p>1. 查询整个映射对象所有字段 </p> <p>Java代码 </p> <ol> <li>//直接from查询出来的是一个映射对象,即:查询整个映射对象所有字段 </li> <li> String hql = "from Users"; </li> <li> Query query = session.createQuery(hql); </li> <li> </li> <li> List<users> users = query.list(); </users></li> <li>for(Users user : users){ </li> <li> System.out.println(user.getName() + " : " + user.getPasswd() + " : " + user.getId()); </li> <li> } </li> <li> </li> <li>输出结果为: </li> <li>name1 : password1 : 1 </li> <li>name2 : password2 : 2 </li> <li>name3 : password3 : 3 </li> </ol> <pre>//直接from查询出来的是一个映射对象,即:查询整个映射对象所有字段 String hql = "from Users"; Query query = session.createQuery(hql); List<users> users = query.list(); for(Users user : users){ System.out.println(user.getName() + " : " + user.getPasswd() + " : " + user.getId()); } 输出结果为: name1 : password1 : 1 name2 : password2 : 2 name3 : password3 : 3 </users></pre> <br>2.查询单个字段 <p>Java代码 </p> <ol> <li>//查询单个字段 </li> <li> String hql = " select name from Users"; </li> <li> Query query = session.createQuery(hql); </li> <li> </li> <li> List<string> list = query.list(); </string></li> <li>for(String str : list){ </li> <li> System.out.println(str); </li> <li> } </li> <li>输出结果为: </li> <li>name1 </li> <li>name2 </li> <li>name3 </li> </ol> <pre>//查询单个字段 String hql = " select name from Users"; Query query = session.createQuery(hql); List<string> list = query.list(); for(String str : list){ System.out.println(str); } 输出结果为: name1 name2 name3 </string></pre> <br>3.查询其中几个字段 <p>Java代码 </p> <ol> <li>//查询其中几个字段 </li> <li> String hql = " select name,passwd from Users"; </li> <li> Query query = session.createQuery(hql); </li> <li>//默认查询出来的list里存放的是一个Object数组 </li> <li> List<object> list = query.list(); </object> </li> <li>for(Object[] object : list){ </li> <li> String name = (String)object[0]; </li> <li> String passwd = (String)object[1]; </li> <li> </li> <li> System.out.println(name + " : " + passwd); </li> <li> } </li> <li>输出结果为: </li> <li>name1 : password1 </li> <li>name2 : password2 </li> <li>name3 : password3 </li> </ol> <pre>//查询其中几个字段 String hql = " select 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 List<object> list = query.list(); for(Object[] object : list){ String name = (String)object[0]; String passwd = (String)object[1]; System.out.println(name + " : " + passwd); } 输出结果为: name1 : password1 name2 : password2 name3 : password3 </object></pre> <br>4.修改默认查询结果(query.list())不以Object[]数组形式返回,以List形式返回 <p>引用</p> <p>//查询其中几个字段,添加new list(),注意list里的l是小写的。也不需要导入包,这样通过query.list()出来的list里存放的不再是默认的Object数组了,而是List集合了 <br> String hql = " select new list(name,passwd) from Users"; <br> Query query = session.createQuery(hql); <br> //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List集合了 <br> List<list> list = query.list(); <br> for(List user : list){ <br> String name = (String)user.get(0); <br> String passwd = (String)user.get(1); <br> System.out.println(name + " : " + passwd); <br> } <br> /** <br> 输出结果为: <br> name1 : password1 <br> name2 : password2 <br> name3 : password3 <br> */ </list></p> <p>5.修改默认查询结果(query.list())不以Object[]数组形式返回,以Map形式返回 </p> <p>Java代码 </p> <ol> <li>//查询其中几个字段,添加new map(),注意map里的m是小写的。也不需要导入包,这样通过query.list()出来的list里存放的不再是默认的Object数组了,而是map集合了 </li> <li> String hql = " select new map(name,passwd) from Users"; </li> <li> Query query = session.createQuery(hql); </li> <li>//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Map集合了 </li> <li> List<map> list = query.list(); </map> </li> <li>for(Map user : list){ </li> <li>//一条记录里所有的字段值都是map里的一个元素,key是字符串0,1,2,3....,value是字段值 </li> <li>//如果将hql改为:String hql = " select new map(name as username,passwd as password) from Users";,那么key将不是字符串0,1,2...了,而是"username","password"了 </li> <li> String name = (String)user.get("0");//get("0");是get(key),注意:0,1,2...是字符串,而不是整形 </li> <li> String passwd = (String)user.get("1"); </li> <li> </li> <li> System.out.println(name + " : " + passwd); </li> <li> } </li> <li>/** </li> <li> 输出结果为: </li> <li> name1 : password1 </li> <li> name2 : password2 </li> <li> name3 : password3 </li> <li> */ </li> </ol> <pre>//查询其中几个字段,添加new map(),注意map里的m是小写的。也不需要导入包,这样通过query.list()出来的list里存放的不再是默认的Object数组了,而是map集合了 String hql = " select new map(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Map集合了 List<map> list = query.list(); for(Map user : list){ //一条记录里所有的字段值都是map里的一个元素,key是字符串0,1,2,3....,value是字段值 //如果将hql改为:String hql = " select new map(name as username,passwd as password) from Users";,那么key将不是字符串0,1,2...了,而是"username","password"了 String name = (String)user.get("0");//get("0");是get(key),注意:0,1,2...是字符串,而不是整形 String passwd = (String)user.get("1"); System.out.println(name + " : " + passwd); } /** 输出结果为: name1 : password1 name2 : password2 name3 : password3 */ </map></pre> <br>6.修改默认查询结果(query.list())不以Object[]数组形式返回,以Set形式返回,但是因为Set里是不允许有重复的元素,所以:username和password的值不能相同。只需将hql改为:String hql = " select new set(name,passwd) from Users"; <br>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 <br>自定义类: <p>Java代码 </p> <ol> <li>package com.domain; </li> <li> </li> <li>public class MyUser { </li> <li> </li> <li>private String username; </li> <li>private String password; </li> <li>//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 </li> <li>public MyUser(String username,String password){ </li> <li>this.username = username; </li> <li>this.password = password; </li> <li> } </li> <li> </li> <li>public String getUsername() { </li> <li>return username; </li> <li> } </li> <li>public void setUsername(String username) { </li> <li>this.username = username; </li> <li> } </li> <li>public String getPassword() { </li> <li>return password; </li> <li> } </li> <li>public void setPassword(String password) { </li> <li>this.password = password; </li> <li> } </li> <li> </li> <li> </li> <li>} </li> </ol> <pre>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; } } </pre> <p>Java代码 </p> <ol> <li>//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 </hibernate-mapping></li> <li> String hql = " select new com.domain.MyUser(name,passwd) from Users"; </li> <li> Query query = session.createQuery(hql); </li> <li>//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 </li> <li> List<myuser> myUsers = query.list(); </myuser></li> <li>for(MyUser myUser : myUsers){ </li> <li> String name = myUser.getUsername(); </li> <li> String passwd = myUser.getPassword(); </li> <li> System.out.println(name + " : " + passwd); </li> <li> } </li> <li>/** </li> <li> 输出结果为: </li> <li> name1 : password1 </li> <li> name2 : password2 </li> <li> name3 : password3 </li> <li> */ </li> </ol> <pre>//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 */ </myuser></hibernate-mapping></pre> <br>8:条件查询 <p>Java代码 </p> <ol> <li>//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 </li> <li> String hql = "from Users where name=? and passwd=?"; </li> <li> Query query = session.createQuery(hql); </li> <li>//第1种方式 </li> <li>// query.setString(0, "name1"); </li> <li>// query.setString(1, "password1"); </li> <li>//第2种方式 </li> <li> query.setParameter(0, "name1",Hibernate.STRING); </li> <li> query.setParameter(1, "password1",Hibernate.STRING); </li> <li> List<users> list = query.list(); </users></li> <li>for(Users users : list){ </li> <li> System.out.println(users.getId()); </li> <li> } </li> </ol> <pre>//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()); } </users></pre> <p>Java代码 </p> <ol> <li>//条件查询,自定义索引名(参数名):username,:password.通过setString,setParameter设置参数 </li> <li> String hql = "from Users where name=:username and passwd=:password"; </li> <li> Query query = session.createQuery(hql); </li> <li>//第1种方式 </li> <li>// query.setString("username", "name1"); </li> <li>// query.setString("password", "password1"); </li> <li>//第2种方式,第3个参数确定类型 </li> <li> query.setParameter("username", "name1",Hibernate.STRING); </li> <li> query.setParameter("password", "password1",Hibernate.STRING); </li> <li> List<users> list = query.list(); </users></li> <li>for(Users users : list){ </li> <li> System.out.println(users.getId()); </li> <li> } </li> </ol> <pre>//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()); } </users></pre> <p>Java代码 </p> <ol> <li>//条件查询,通过setProperties设置参数 </li> <li> String hql = "from Users where name=:username and passwd=:password"; </li> <li> Query query = session.createQuery(hql); </li> <li>//MyUser类的2个属性必须和:username和:password对应 </li> <li> MyUser myUser = new MyUser("name1","password1"); </li> <li> query.setProperties(myUser); </li> <li> List<users> list = query.list(); </users></li> <li>for(Users users : list){ </li> <li> System.out.println(users.getId()); </li> <li> } </li> </ol>转载地址:http://xcaji.baihongyu.com/