easyui-datagrid通过action从数据库获取数据的关键代码

Posted 2020-08-09 Sunnor

 

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：