java与前端交互的方式

第一种、通过session存取值

  Session会话域，Session在用户访问第一次访问服务器时创建，服务器会把长时间没有活动的Session从服务器内存中清除，此时Session便失效。Tomcat中Session的默认失效时间为20分钟。另可调用Session的invalidate方法使其失效。

jsp部分：

<%@ page language="java" contentType="text/html; charset=UTF-8"  
    pageEncoding="UTF-8"%>  
  
  
  
  
  
  
  
    
  
        
  
        
<%=session.getAttribute("username")%>
  
  
  

java部分：

package com.cool.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * Servlet implementation class SessionServ
 */
@WebServlet("/SessionServ")
public class SessionServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public SessionServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		this.doPost(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		HttpSession session=request.getSession();
		session.setAttribute("username","吴彦祖");

		//重定向回到先前页面
		request.getRequestDispatcher("SessionTest.jsp").forward(request, response);
	}

}

第二种、ajax存取单个数据

jsp部分：

<%@page import="java.util.*" language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>  
     <%@taglib uri="/struts-tags" prefix="s" %>








	
ajax数据交互demo
	
	

java部分：

package com.cool.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.opensymphony.xwork2.ActionContext;

/**
 * Servlet implementation class TestServlet
 */
@WebServlet("/TestServlet")
public class TestServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public TestServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		this.doPost(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.setContentType("text/html;charset=UTF-8");
		PrintWriter out=response.getWriter();
		out.print("ajax交互成功！");
	}

}

第三种、json存取多个对象或数据

jsp部分：

<%@page import="java.util.*" language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>  
     <%@taglib uri="/struts-tags" prefix="s" %>








	
json数据交互demo
	
	

java部分：

package com.cool.servlet;

import java.awt.List;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.cool.bean.Student;

import net.sf.json.JSONArray;

/**
 * Servlet implementation class JsonServlet
 */
@WebServlet("/JsonServlet")
public class JsonServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public JsonServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		this.doPost(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		ArrayList list=new ArrayList();
		for(int i=0;i<3;i++){
			Student stu=new Student();
			stu.setName("Tom");
			stu.setSex("男");
			stu.setAge(i+10);
			list.add(stu);
		}
		response.setContentType("text/html;charset=utf-8");
		PrintWriter out=response.getWriter();
		out.print(JSONArray.fromObject(list));
		out.flush();
		out.close();
	}

}

第四种、html赋值

   总所周知，input有个属性是hidden，它可以使input隐藏但不占用空间。因此，我们可以把想要传递到后台的数据储存到value，让后台通过标识获得这个数据。

jsp部分：

java部分：

String stu_name=request.getParameter("stu_name")

如果还有其他数据交互的方法，欢迎补充；若文中尚有不妥之处，希望可以得到您的纠正。