easyui-datagrid通过action从数据库获取数据的关键代码

 

实际上是结合struts2来从数据获取json格式的数据。

 

关键代码：

GetUserAction.java代码

 

package com.log.control;

import java.io.IOException;

import java.io.StringWriter;

import java.util.ArrayList;

import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts2.ServletActionContext;

import org.codehaus.jackson.JsonFactory;

import org.codehaus.jackson.JsonGenerator;

import org.codehaus.jackson.map.ObjectMapper;

import com.log.entity.User4;

import com.opensymphony.xwork2.ActionSupport;

 

/**

 * 用于从数据库获取数据

 * @author Wei

 * @time   2016年9月19日 上午12:45:39

 */

public class GetUserAction extends ActionSupport {

       private User4 user ;

       /**

       *

       */

       private static final long serialVersionUID = 1L;

       /**

       * 获取json格式字符串

       * @param obj

       * @return

       */

       public String getJsonString(Object obj ) {

            ObjectMapper om = new ObjectMapper();

            StringWriter sw = new StringWriter();

             try {

                  JsonGenerator jg = new JsonFactory().createJsonGenerator( sw );

                   om .writeValue( jg , obj );

                   jg .close();

            } catch (IOException e ) {

                   // TODO Auto-generated catch block

                   e .printStackTrace();

            }

             return sw .toString();

      }

       /**

       * 把从数据库获取到的数据 List <User4> list 写到页面上

       * @param obj

       */

       public void writeJson(Object obj ) {

            String json = getJsonString( obj );

             try {

                  ServletActionContext.getResponse().setContentType( "text/html;charset=utf-8" );

                  ServletActionContext.getResponse().getWriter().write( json );

            } catch (IOException e ) {

                   // TODO Auto-generated catch block

                   e .printStackTrace();

            }

      }

       /**

       *

       */

       @Override

       public String execute() throws Exception {

             // easyui-datagrid表格 点击下一页的时候 的参数 page=2&rows=11&sort=email&order=DESC

            HttpServletRequest req = ServletActionContext.getRequest();

             //System.out.println("---11111---page:"+req.getParameter("page"));

             //System.out.println("GetUserAction.java----------"+req.getQueryString());

            UserDao dao = new UserDao();

             //开启hibernate的transaction等

             dao .init();

            List<User4> list = new ArrayList<User4>();

             for ( int i =1; i <20; i ++){

                   //通过hibernate从数据库获取数据，放到list中

                   list .add((User4) dao . session .get(User4. class , i ));

            }

             //销毁hibernate相关的资源

             dao .destroy();

             //写到页面上

            writeJson( list );

             return null ;

      }

}

 

UserDao.java代码

package com.log.control;

import java.sql.Date;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.Transaction;

import org.hibernate.cfg.Configuration;

import org.hibernate.service.ServiceRegistry;

import org.hibernate.service.ServiceRegistryBuilder;

import org.junit.After;

import org.junit.Before;

import org.junit.Test;

public class UserDao {

//    private SessionFactory sessionFactory;

//    private Session session;

//    private Transaction transaction;

      

       public SessionFactory sessionFactory ;

       public Session session ;

       public Transaction transaction ;

//    @Before

       public void init() {

            Configuration configuration = new Configuration().configure();

            ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings( configuration .getProperties())

                        .buildServiceRegistry();

             sessionFactory = configuration .buildSessionFactory( serviceRegistry );

             session = sessionFactory .openSession();

             transaction = session .beginTransaction();

      }

//    @After

       public void destroy() {

             transaction .commit();

             session .close();

             sessionFactory .close();

      }

//    @Test

       public void testInsert() {

            UserDao dao = new UserDao();

             dao .init();

             for ( int i = 43; i < 64; i ++) {

                   dao . session

                              .save( new User4(55, "xiaohong" + i , "qq" + i + "@163.com" , new Date(System.currentTimeMillis())));

            }

             dao .destroy();

      }

}

 

 具体页面展示：

 

 

 

 

 

 

 

 

获取到的json数据：