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：