如何使用jquery將json數組發布到java servlet

Question

我目前正在開發spring mvc應用程序，我需要發布JSON array 。

當我訪問request.getParameter("paramValue")來獲取param attibute時，它返回一個null值，

這是我的前端代碼：

$.ajax(url, {
    async: true,
    type: 'post',
    contentType: 'application/json',
    data:  JSON.stringify({
        "test":"test value"
    })
}).done(function (response) {
    console.log(data);
}).fail(function (xhr) {
    console.log("request failed");
    console.log(xhr);
});

這是我的服務器端代碼：

@RequestMapping(value = "/Products", method = RequestMethod.POST)
public void saveProducts(HttpServletRequest req, HttpServletResponse res) throws Exception {

    System.out.println(req.getContentType());
    System.out.println(req.getContentLength());
    System.out.println(req.getContextPath());
    System.out.println(req.getParameterValues("test"));
    System.out.println(req.getMethod());

    StringBuilder buffer = new StringBuilder();
    BufferedReader reader = req.getReader();
    String line;
    while ((line = reader.readLine()) != null) {
        buffer.append(line);
    }
    String data = buffer.toString();

    System.out.println(data);

    System.out.println(req.getParameter("test"));
}

輸出是：

application/json
22

null
POST
{"test" : "Test DAta"}
null

我無法弄清楚發生了什么，請幫助我。

Answer 1

在你的ajax函數中刪除這一行

contentType: 'application/json',

並替換此行

data:  JSON.stringify({
        "test":"test value"
    })

同

data: {
   "test":"test value"
}

而你也可以使用

req.getParameter("test")

代替

req.getParameterValues("test")

Answer 2

你可以使用這個：

var data ={id: 1, name :'test'}


       $.ajax(url, {
        async: true,
        type: 'post',
        contentType: 'application/json',
        data: data
    }).done(function (response) {
        console.log(data);
    }).fail(function (xhr) {
        console.log("request failed");
        console.log(xhr);
    });

並在服務器端創建一個pojo：

public class Product{
  private long id;
  private String name;
 // getters and setters

添加庫傑克遜。

在您的控制器中添加此方法：

@RequestMapping(value = "/Products", method = RequestMethod.POST)
public RepsoneEntity<? >saveProducts(@requestBody Product pr){
     LOG.debug(pr.toString());
  return new reRepsoneEntity<Product>(pr,HttpStatus.ACCEPTED);
}

Answer 3

我最后修改了幾個注釋並更改了服務器端方法的返回類型，

@RequestMapping(value = "/Products", method = RequestMethod.POST, produces = "application/json;charset=UTF-8")

 public ResponseEntity<?> saveProducts(@RequestParam(value = "data") String brand) { return ResponseEntity.ok(brand); }</code> front end $.ajax(url, { async: true, type: "POST", data: {"data" : JSON.stringify({"Brand" : "Test Brand"})}   

public ResponseEntity<?> saveProducts(@RequestParam(value = "data") String brand) { return ResponseEntity.ok(brand); }</code> front end $.ajax(url, { async: true, type: "POST", data: {"data" : JSON.stringify({"Brand" : "Test Brand"})}

public ResponseEntity<?> saveProducts(@RequestParam(value = "data") String brand) { return ResponseEntity.ok(brand); }</code> front end $.ajax(url, { async: true, type: "POST", data: {"data" : JSON.stringify({"Brand" : "Test Brand"})}

public ResponseEntity<?> saveProducts(@RequestParam(value = "data") String brand) { return ResponseEntity.ok(brand); }</code> front end $.ajax(url, { async: true, type: "POST", data: {"data" : JSON.stringify({"Brand" : "Test Brand"})}

  }).done(function (response) { console.log(response); }).fail(function (xhr) { console.log("request failed"); console.log(xhr); }); 

我使用org.json來訪問解析為文本的json對象，使用gson來處理POJO

現在它的工作原理:)