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servlet如何获取PUT和DELETE请求的参数

news 2025/8/14 17:18:02

1. servlet为何不能获取PUT和DELETE请求的参数

Servlet的规范是POST的数据需要转给request.getParameter*()方法，没有规定PUT和DELETE请求也这么做

The Servlet spec requires form data to be available for HTTP POST but not for HTTP PUT or PATCH requests. This filter intercepts HTTP PUT and PATCH requests where content type is 'application/x-www-form-urlencoded', reads form encoded content from the body of the request, and wraps the ServletRequest in order to make the form data available as request parameters just like it is for HTTP POST requests.

2. 解决方案

2-1 前端使用ajax请求时，发送json类型的参数

2-2 后端使用字符流读取前端传递的参数

3. 具体的实现

3-1 前端部分

$(function () {// 1. 请求参数let params = {id: 51,phone: '17911113333',userCode: 'barrss',userName: 'barrss',address: '不详',userRole: 1,gender: 1,birthday: '1998-10-12',}// 2. 使用jQuery的$.ajax()发送put类型请求进行用户修改$.ajax({url: 'http://localhost/day81/updateUser',// 请求类型是puttype: 'put',dataType: 'json',// 通过请求头告诉服务端，发送的数据是json类型contentType: 'application/json',// 前端必须传递json字符串，否则后端无法解析data: JSON.stringify(params),headers: { token: '***.***zAyMjYwfQ.***' },success(res) {console.log(res)},error(e) {console.log(e)},})
})

3-2 后端MyUtil工具类中定义方法 getJSONParams

/***  获得前端发送的json类型参数** @param req 封装客户端请求信息的对象* @return 包含请求参数的Map集合*/public static Map<String, String> getJSONParams(HttpServletRequest req) throws ServletException, IOException {// 1. 打开输入流读取客户端写入的json字符串InputStream in = req.getInputStream();// 2. 使用BufferedReader包装流，指定字符串BufferedReader reader = new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8));String str = null;StringBuilder builder = new StringBuilder();// 3. 读取客户端传递的json字符串参数，拼接到StringBuilder中while ((str = reader.readLine()) != null) {builder.append(str);}String params = builder.toString();// 4. 去除json字符串中的{}params = params.substring(1, params.length() - 1);// 5. 去除json字符串中的 "params = params.replace("\"", "");Map<String, String> map = new HashMap<>();// 6. 拆分字符串，把key=value键值对, 存放到map中String[] arr = params.split(",");for (String item : arr) {String[] code = item.split(":");map.put(code[0], code[1]);}return map;}

3-3 servlet中的doPut方法中使用getJSONParams即可

  @Overrideprotected void doPut(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {Map<String, String> map = MyUtil.getJSONParams(req);req.setAttribute("params", map);doPost(req, res);}