如何使用Java HttpServer/HttpExchange获取GET中的查询字符串？

query-string get java httpserver

2022-09-01 14:00:25

我试图在Java中创建一个简单的HttpServer来处理GET请求，但是当我尝试获取请求的GET参数时，我注意到HttpExchange类没有这方面的方法。

有没有人知道一种简单的方法来读取GET参数（查询字符串）？

这是我的处理程序的样子：

public class TestHandler{
  @Override
  public void handle(HttpExchange exc) throws IOxception {
    String response = "This is the reponse";
    exc.sendResponseHeaders(200, response.length());

    // need GET params here

    OutputStream os = exc.getResponseBody();
    os.write(response.getBytes());
    os.close();
  } 
}

..和主要方法：

public static void main(String[] args) throws Exception{
  // create server on port 8000
  InetSocketAddress address = new InetSocketAddress(8000);
  HttpServer server = new HttpServer.create(address, 0);

  // bind handler
  server.createContext("/highscore", new TestHandler());
  server.setExecutor(null);
  server.start();
}

答案 1

以下是：httpExchange.getRequestURI().getQuery()

将以类似于以下内容的格式返回字符串："field1=value1&field2=value2&field3=value3..."

所以你可以自己简单地解析字符串，这就是解析函数的样子：

public Map<String, String> queryToMap(String query) {
    if(query == null) {
        return null;
    }
    Map<String, String> result = new HashMap<>();
    for (String param : query.split("&")) {
        String[] entry = param.split("=");
        if (entry.length > 1) {
            result.put(entry[0], entry[1]);
        }else{
            result.put(entry[0], "");
        }
    }
    return result;
}

这就是你如何使用它：

Map<String, String> params = queryToMap(httpExchange.getRequestURI().getQuery()); 
System.out.println("param A=" + params.get("A"));

答案 2

这个答案与 annon01 的答案相反，它正确地解码了键和值。它不使用，而是使用扫描字符串，这更快。String.splitindexOf

public static Map<String, String> parseQueryString(String qs) {
    Map<String, String> result = new HashMap<>();
    if (qs == null)
        return result;

    int last = 0, next, l = qs.length();
    while (last < l) {
        next = qs.indexOf('&', last);
        if (next == -1)
            next = l;

        if (next > last) {
            int eqPos = qs.indexOf('=', last);
            try {
                if (eqPos < 0 || eqPos > next)
                    result.put(URLDecoder.decode(qs.substring(last, next), "utf-8"), "");
                else
                    result.put(URLDecoder.decode(qs.substring(last, eqPos), "utf-8"), URLDecoder.decode(qs.substring(eqPos + 1, next), "utf-8"));
            } catch (UnsupportedEncodingException e) {
                throw new RuntimeException(e); // will never happen, utf-8 support is mandatory for java
            }
        }
        last = next + 1;
    }
    return result;
}