2种跨域解决方案

第一种（jsonp）：http://www.cnblogs.com/Garnett-Boy/p/6222870.html 

第二种：（CORS）：只需要在服务器端返回查询结果时添加,这样只需要修改后台服务代码就可以实现浏览器的跨域请求了。

response.addHeader("Access-Control-Allow-Origin", "*");
response.addHeader("Access-Control-Allow-Methods", "GET,POST");

代码：

package com.sxdx.employee.action;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSON;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import com.sxdx.employee.dao.employeeDao;
import com.sxdx.employee.domain.employee;
import com.sxdx.employee.service.employeeImpl;

@Controller
@RequestMapping(value="/employeeAction")
public class employeeAction {
    @RequestMapping(value="/showEmployeeList.do")
    public String showEmployeeList(HttpServletRequest request,HttpServletResponse response){
        JSONObject jsonboject=new JSONObject();
        JSONArray rows = new JSONArray();
        System.out.println(request.getParameter("pageNumber"));
        System.out.println(request.getParameter("pageSize"));
        employeeDao empDao=new employeeImpl();
        System.out.println(empDao.selectAll());
        for(employee emp:empDao.selectAll()){
            JSONObject cell = new JSONObject();
            cell.put("eid", emp.getEid());
            cell.put("ename", emp.getEname());
            cell.put("esex", emp.getEsex());
            cell.put("eage", emp.getEage());
            rows.add(cell);
        }
        jsonboject.put("rows", rows);
        jsonboject.put("total", empDao.selectAll().size());
        
        PrintWriter out = null;
          try {
              response.setCharacterEncoding("UTF-8"); //设置编码格式  
              //response.setContentType("text/html");   //设置数据格式  
              String act = request.getParameter("act");//是否跨域请求,在请求时通过参数传递，以便后面判断是否需要按照跨域请求做返回
              out = response.getWriter(); 
              if(act.equals("area")){//如果是跨域请求执行此分支
                  response.addHeader("Access-Control-Allow-Origin", "*");
                  response.addHeader("Access-Control-Allow-Methods", "GET,POST");
                  //String callback=request.getParameter("callback");//此处即为跨域请求核心操作，回调方法
                  //out.write(callback+"('"+rows.toString()+"')");
                  out.write(rows.toString());
              }else{
                  out.write(rows.toString());  
              }
              out.flush();  
          } catch (IOException e) {
              e.printStackTrace();  
          } finally{
              out.close();
          }
        return null;
    }
}