JavaScript请求后台数据的几种常用方式

0、本博客所用到的服务器端的代码

@WebServlet(urlPatterns = "/demoServlet")
public class DemoServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String data = request.getParameter("data");
        response.getWriter().write("{'data':'"+data+"'}");
        System.out.println("doPost："+data);
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String data = request.getParameter("data");
        response.getWriter().write("{'data':'"+data+"'}");
        System.out.println("doGet："+data);
    }
}

1、window.location.href

    
        
        JavaScript请求后台
        
            function fun() {
                window.location.href="${pageContext.request.contextPath}/demoServlet?data=haha";
            }
        
    
    
        请求
    

2、window.open()

把js中的值传到后台，区别是后台请求后台之后，默认会打开新的浏览器窗口。

    
        
        JavaScript请求后台
        
            function fun() {
                // window.open("${pageContext.request.contextPath}/demoServlet?data=haha"); //打开新的窗口
                window.open("${pageContext.request.contextPath}/demoServlet?data=haha","_self"); //在原窗口中撕开
            }
        
    
    
        请求
    

3、.submit()方法提交表单

    
        
        JavaScript请求后台
        
            function fun() {
                var form = document.forms["form1"];
                form.action="${pageContext.request.contextPath}/demoServlet";
                form.method="GET";
                form.submit();
            }
        
    
    
        
            
        
        请求
    

4、.submit()方法提交表单

    
        
        JavaScript请求后台
        
            function fun() {
               var form = document.createElement("form");
               //form.action="${pageContext.request.contextPath}/demoServlet?data=haha"; //这种方式不能将数据传递到后台
               form.action="${pageContext.request.contextPath}/demoServlet";

               var input = document.createElement("input");
               input.name="data";
               input.value= "haha";
               form.appendChild(input);

               form.method="GET";
               document.body.appendChild(form);
               form.submit();
            }
        
    
    
        请求
    

5、自定义AJAX

    
        
        JavaScript请求后台
        
            function fun() {
                var xhr;
                if (window.XMLHttpRequest) {
                    xhr = new window.XMLHttpRequest;
                } else {
                    xhr = new ActiveXObject("Microsoft.XMLHTTP");
                }
                xhr.onreadystatechange = success;
                var url="${pageContext.request.contextPath}/demoServlet?data=haha";
                xhr.open("POST", url, false);
                xhr.send();

                function success() {
                    if (xhr.readyState == 4 && xhr.status == 200) { //回传成功
                        console.info(xhr.responseText);
                        return true;
                    } else {
                        return false;
                    }
                }
            }
        
    
    
        请求
    

6、使用JQuery

请参看博客：JQuery AJAX