从HttpURLConnection对象解析JSON [英] Parse JSON from HttpURLConnection object

问题描述

我正在使用Java中的 HttpURLConnection 对象进行基本的http认证。

I am doing basic http auth with the HttpURLConnection object in Java.

        URL urlUse = new URL(url);
        HttpURLConnection conn = null;
        conn = (HttpURLConnection) urlUse.openConnection();
        conn.setRequestMethod("GET");
        conn.setRequestProperty("Content-length", "0");
        conn.setUseCaches(false);
        conn.setAllowUserInteraction(false);
        conn.setConnectTimeout(timeout);
        conn.setReadTimeout(timeout);
        conn.connect();

        if(conn.getResponseCode()==201 || conn.getResponseCode()==200)
        {
            success = true;
        }

我期待一个JSON对象或字符串数​​据格式为有效JSON对象，或带有有效JSON的简单纯文本的HTML。如何在返回响应后从 HttpURLConnection 访问它？

I am expecting a JSON object, or string data in the format of a valid JSON object, or HTML with simple plain text that is valid JSON. How do I access that from the HttpURLConnection after it returns a response?

推荐答案

<你可以使用下面的方法获取原始数据。顺便说一下，这种模式适用于Java 6.如果您使用的是Java 7或更新版本，请考虑 try-with-resources模式。

public String getJSON(String url, int timeout) {
    HttpURLConnection c = null;
    try {
        URL u = new URL(url);
        c = (HttpURLConnection) u.openConnection();
        c.setRequestMethod("GET");
        c.setRequestProperty("Content-length", "0");
        c.setUseCaches(false);
        c.setAllowUserInteraction(false);
        c.setConnectTimeout(timeout);
        c.setReadTimeout(timeout);
        c.connect();
        int status = c.getResponseCode();

        switch (status) {
            case 200:
            case 201:
                BufferedReader br = new BufferedReader(new InputStreamReader(c.getInputStream()));
                StringBuilder sb = new StringBuilder();
                String line;
                while ((line = br.readLine()) != null) {
                    sb.append(line+"\n");
                }
                br.close();
                return sb.toString();
        }

    } catch (MalformedURLException ex) {
        Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
    } catch (IOException ex) {
        Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
    } finally {
       if (c != null) {
          try {
              c.disconnect();
          } catch (Exception ex) {
             Logger.getLogger(getClass().getName()).log(Level.SEVERE, null, ex);
          }
       }
    }
    return null;
}

然后您可以使用带有 Google Gson 将JSON映射到指定类的对象，如下所示：

And then you can use returned string with Google Gson to map JSON to object of specified class, like this:

String data = getJSON("http://localhost/authmanager.php");
AuthMsg msg = new Gson().fromJson(data, AuthMsg.class);
System.out.println(msg);

有一个AuthMsg类的样本：

There is a sample of AuthMsg class:

public class AuthMsg {
    private int code;
    private String message;

    public int getCode() {
        return code;
    }
    public void setCode(int code) {
        this.code = code;
    }

    public String getMessage() {
        return message;
    }
    public void setMessage(String message) {
        this.message = message;
    }
}

由 http：//localhost/authmanager.php 必须如下所示：

JSON returned by http://localhost/authmanager.php must look like this:

{"code":1,"message":"Logged in"}

问候

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