javaajax将值从jsp传递到servlet_Java_Jquery_Ajax_Jsp_Servlets

javaajax将值从jsp传递到servlet

java jquery ajax jsp servlets

javaajax将值从jsp传递到servlet,java,jquery,ajax,jsp,servlets,Java,Jquery,Ajax,Jsp,Servlets,我试图通过ajax将基本值（如id）从jsp传递到servlet。我尝试了所有方法，但只传递了null。即使console.log（val）也不会将任何内容打印到浏览器控制台我的理解是：网页有表单值，onsubmit调用js文件。js有ajax，它调用servlet并传递表单的数据。servlet通过request.getParameter（val）这是我的密码： Main.jsp <%@ page language="java" contentType="text/html; cha

我试图通过ajax将基本值（如id）从jsp传递到servlet。我尝试了所有方法，但只传递了null。即使

console.log（val）

也不会将任何内容打印到浏览器控制台

我的理解是：网页有表单值，onsubmit调用js文件。js有ajax，它调用servlet并传递表单的数据。servlet通过

request.getParameter（val）

这是我的密码：

Main.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js" type="text/javascript">
<script src="js/main.js" type="text/javascript"></script>
</head>
<body>

<form method="post" action="Main" id="firstform">
    <h1>Enter name:</h1>
    <input type="text" name="id" id="id" />
    <input type="submit" name="submit"/>
</form>

</body>
</html>

package servlets;

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;

/**
 * Servlet implementation class Main
 */
@WebServlet("/Main")
public class Main extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Main() {
        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
        int ids;
        response.setContentType("text/html;charset=UTF-8");

        PrintWriter out = response.getWriter();
        String val = request.getParameter("id");
        System.out.print(val);
        if(val != null){
            ids = Integer.parseInt(val);
            out.print(ids); //
        }

    }

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

}

Main.java

package servlets;

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;

/**
 * Servlet implementation class Main
 */
@WebServlet("/Main")
public class Main extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Main() {
        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
        int ids;
        response.setContentType("text/html;charset=UTF-8");

        PrintWriter out = response.getWriter();
        String val = request.getParameter("id");
        System.out.print(val);
        if(val != null){
            ids = Integer.parseInt(val);
            out.print(ids); //
        }

    }

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

}

**问题：
1）从jsp传递到servlet的值
2） console.log不会在浏览器控制台上打印任何内容

1）可以工作，但2）仍然不能。**

在main.js中类型是

类型：“post”

并且您已经在get方法中编写了代码

输入：'get'

输入字段中没有name属性。当你在做

String val = request.getParameter("id");

然后在servlet中，它将搜索具有

name=“id”

的输入字段，但在您的表单中没有任何内容，因此它将返回

null

为输入字段命名，如

<input type="text" id="id" name="id"/>

另外，正如sanjay所说，您的ajax已经键入post，因此也将其更改为

get

，仅用于控制台。日志（数据）问题可能是$.ajax（）函数与响应类型混淆，请尝试以下操作：

Ajax

package servlets;

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;

/**
 * Servlet implementation class Main
 */
@WebServlet("/Main")
public class Main extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Main() {
        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
        int ids;
        response.setContentType("text/html;charset=UTF-8");

        PrintWriter out = response.getWriter();
        String val = request.getParameter("id");
        System.out.print(val);
        if(val != null){
            ids = Integer.parseInt(val);
            out.print(ids); //
        }

    }

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

}

$.ajax({
    url: 'Main',
    data: form.serialize(),
    type: 'post',
    dataType:'text/plain',
    success: function(data){ 
        console.log(data);
    }
});

Servlet

package servlets;

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;

/**
 * Servlet implementation class Main
 */
@WebServlet("/Main")
public class Main extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Main() {
        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
        int ids;
        response.setContentType("text/html;charset=UTF-8");

        PrintWriter out = response.getWriter();
        String val = request.getParameter("id");
        System.out.print(val);
        if(val != null){
            ids = Integer.parseInt(val);
            out.print(ids); //
        }

    }

    /**
     * @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/plain;charset=UTF-8");

将此更改的名称属性改为trued@www.sblog.in，但仍然不起作用尝试在表单中登录。submit（）并查看得到的值。还要检查form.serialize（）@fscore你得到答案了吗？我现在改为“post”，但仍然没有结果。它甚至不会像这里提到的那样在java控制台上打印-System.out.print（val）；所以类型应该是“get”，而不是post。。。我接受了你的回答，尽管。。console.log仍不能运行work@fscore首先尝试在不使用ajax的情况下提交表单，如果您得到任何值或值，请告诉我not@fscore你是说这行console.log（“gi”）；是的，它不打印。事实上，即使我做了console.log（id），它也不会打印出来too@fscore如果没有错误，那么您至少应该在console.log（“gi”）；中获取此信息；。至少gi会被打印出来