JavaWeb_(Hibernate框架)Hibernate中数据查询语句SQL基本用法

2022-03-19 22:19:02

本文展示三种在Hibernate中使用SQL语句进行数据查询基本用法

　　1、基本查询

　　2、条件查询

　　3、分页查询

package com.Gary.dao;

import java.util.List;

import org.hibernate.Session;

import org.hibernate.Transaction;

import org.hibernate.query.NativeQuery;

import com.Gary.domain.User;

import com.Gary.utils.HibernateUtils;

public class SQLDao {

    public void find()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user";

        //创建sql查询对象

        NativeQuery query = session.createSQLQuery(sql);

        query.addEntity(User.class);

        //接收list

        List<User> list = query.list();

        //接收单一返回值  query.uniqyeResult();

        //输出第一个成员姓名

        System.out.println(list.get(0).getUsername());

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

    //SQL条件查询

    public void find2()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user where id = ?";

        //创建SQL查询对象

        NativeQuery query = session.createSQLQuery(sql);

        //封装参数,给第一个?赋值

        query.setParameter(1, "1");

        query.addEntity(User.class);

        //唯一返回值

        User user = (User) query.uniqueResult();

        System.out.println(user);

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

    //SQL分页查询

    public void find3()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user limit ? , ?";

        //创建SQL查询对象

        NativeQuery query = session.createSQLQuery(sql);

        //封装参数,给第一个?赋值

        query.setParameter(1, 0);

        //同理

        query.setParameter(2, 2);

        query.addEntity(User.class);

        //唯一返回值

        List<User> list = query.list();

        System.out.println(list.get(0).getUsername());

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

}

SQLDao.java

　　数据库user表

　　向数据库中添加假数据

1、SQL基本查询

　　//开始进行SQL查询

　　String sql = "select * from user";

　　//创建sql查询对象

　　NativeQuery query = session.createSQLQuery(sql);

　　query.addEntity(User.class);

　　SQLDao.java向数据库发起查询请求

public void find()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user";

        //创建sql查询对象

        NativeQuery query = session.createSQLQuery(sql);

        query.addEntity(User.class);

        //接收list

        List<User> list = query.list();

        //接收单一返回值  query.uniqyeResult();

        //输出第一个成员姓名

        System.out.println(list.get(0).getUsername());

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

package com.Gary.dao;

import java.util.List;

import org.hibernate.Session;

import org.hibernate.Transaction;

import org.hibernate.query.NativeQuery;

import com.Gary.domain.User;

import com.Gary.utils.HibernateUtils;

public class SQLDao {

    public void find()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user";

        //创建sql查询对象

        NativeQuery query = session.createSQLQuery(sql);

        query.addEntity(User.class);

        //接收list

        List<User> list = query.list();

        //接收单一返回值  query.uniqyeResult();

        //输出第一个成员姓名

        System.out.println(list.get(0).getUsername());

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

}

SQLDao.java

2、SQL条件查询

        //开始进行SQL查询

        String sql = "select * from user where id = ?";

        //创建SQL查询对象

        NativeQuery query = session.createSQLQuery(sql);

        //封装参数,给第一个?赋值

        query.setParameter(1, "1");

        query.addEntity(User.class);

　　SQLDao.java向数据库发起查询请求

public void find2()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user where id = ?";

        //创建SQL查询对象

        NativeQuery query = session.createSQLQuery(sql);

        //封装参数,给第一个?赋值

        query.setParameter(1, "1");

        query.addEntity(User.class);

        //唯一返回值

        User user = (User) query.uniqueResult();

        System.out.println(user);

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

package com.Gary.dao;

import java.util.List;

import org.hibernate.Session;

import org.hibernate.Transaction;

import org.hibernate.query.NativeQuery;

import com.Gary.domain.User;

import com.Gary.utils.HibernateUtils;

public class SQLDao {

    public void find()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user";

        //创建sql查询对象

        NativeQuery query = session.createSQLQuery(sql);

        query.addEntity(User.class);

        //接收list

        List<User> list = query.list();

        //接收单一返回值  query.uniqyeResult();

        //输出第一个成员姓名

        System.out.println(list.get(0).getUsername());

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

    public void find2()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user where id = ?";

        //创建SQL查询对象

        NativeQuery query = session.createSQLQuery(sql);

        //封装参数,给第一个?赋值

        query.setParameter(1, "1");

        query.addEntity(User.class);

        //唯一返回值

        User user = (User) query.uniqueResult();

        System.out.println(user);

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

}

SQLDao.java

3、SQL分页查询

　　//开始进行SQL查询

　　String sql = "select * from user limit ? , ?";

　　//创建SQL查询对象

　　NativeQuery query = session.createSQLQuery(sql);

　　//封装参数,给第一个?赋值

　　query.setParameter(1, 0);

　　//同理

　　query.setParameter(2, 2);

　　query.addEntity(User.class);

　　//唯一返回值

　　List<User> list = query.list();

　　SQLDao.java向数据库发起查询请求

//SQL分页查询

    public void find3()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user limit ? , ?";

        //创建SQL查询对象

        NativeQuery query = session.createSQLQuery(sql);

        //封装参数,给第一个?赋值

        query.setParameter(1, 0);

        //同理

        query.setParameter(2, 2);

        query.addEntity(User.class);

        //唯一返回值

        List<User> list = query.list();

        System.out.println(list.get(0).getUsername());

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

package com.Gary.dao;

import java.util.List;

import org.hibernate.Session;

import org.hibernate.Transaction;

import org.hibernate.query.NativeQuery;

import com.Gary.domain.User;

import com.Gary.utils.HibernateUtils;

public class SQLDao {

    public void find()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user";

        //创建sql查询对象

        NativeQuery query = session.createSQLQuery(sql);

        query.addEntity(User.class);

        //接收list

        List<User> list = query.list();

        //接收单一返回值  query.uniqyeResult();

        //输出第一个成员姓名

        System.out.println(list.get(0).getUsername());

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

    //SQL条件查询

    public void find2()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user where id = ?";

        //创建SQL查询对象

        NativeQuery query = session.createSQLQuery(sql);

        //封装参数,给第一个?赋值

        query.setParameter(1, "1");

        query.addEntity(User.class);

        //唯一返回值

        User user = (User) query.uniqueResult();

        System.out.println(user);

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

    //SQL分页查询

    public void find3()

    {

        Session session = HibernateUtils.getSession();

        Transaction beginTransaction = session.beginTransaction();

        //开始进行SQL查询

        String sql = "select * from user limit ? , ?";

        //创建SQL查询对象

        NativeQuery query = session.createSQLQuery(sql);

        //封装参数,给第一个?赋值

        query.setParameter(1, 0);

        //同理

        query.setParameter(2, 2);

        query.addEntity(User.class);

        //唯一返回值

        List<User> list = query.list();

        System.out.println(list.get(0).getUsername());

        //结束SQL查询

        beginTransaction.commit();

        session.close();

    }

}

SQLDao.java

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