URLConnection类

柔情只为你懂 2022-09-24 10:30 200阅读 0赞

抽象类 URLConnection 是所有表示应用程序与 URL 之间通信链路的类的超类。该类的实例可以用来对由 URL 引用的资源进行读取和写入操作；  
Java中的流分为两种，一种是字节流，另一种是字符流，字节流继承于抽象类inputStream/outputStream,字符流继承于抽象类Reader/Writer。Java中其他多种多样变化的流均是由它们派生出来的.

直接上例子。

public String Create (String token){ //token 是通过账号和密码取得的口令
          map.put("roomName", aaa);
          map.put("anchorPwd",bbb);
          map.put("assistPwd", cccc);
          map.put("userPwd",ddd);
          String jsonObject = JSONObject.toJSONString(map);//将参数和值放到map里面，转为json字符串，作为参数传递
          result = GotyeUtil.sendPost(url+"Create", jsonObject, token);
          return   result;   //是一个json对象{ aaa:[],bbb:[]}
    
    public static String sendPost(String url, String param,String token) {
        //PrintWriter out = null;
        //需要用outputStreamWriter
        OutputStreamWriter out=null;
        BufferedReader in = null;  
        String result = "";  
        try {  
            URL realUrl = new URL(url);  
            //打开和URL之间的连接 调用URL对象openConnection()方法来创建URLConnection对象
            URLConnection conn = realUrl.openConnection();  
            //设置通用的请求属性 
            conn.setRequestProperty("Accept", "application/json");  
            conn.setRequestProperty("connection", "Keep-Alive");  
            conn.setRequestProperty("user-agent","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)");
            conn.setRequestProperty("Content-Type", "application/json");
            conn.setRequestProperty("Authorization", token);
            //发送POST请求必须设置如下两行 
            conn.setDoOutput(true);  
            conn.setDoInput(true);  
            //获取URLConnection对象对应的输出流
             out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
            //out = new PrintWriter(conn.getOutputStream());
            //发送请求参数
            out.append(param);
            //out.print(param);
            //flush输出流的缓冲 
            out.flush();  
            //定义BufferedReader输入流来读取URL的响应 
            in = new BufferedReader(  
                new InputStreamReader(conn.getInputStream(),"UTF-8"));
    
            String line;  
            while ((line = in .readLine()) != null) {
                result +=  line;
            }  
        } catch (Exception e) {  
            System.out.println("发送POST请求出现异常！" + e);  
            e.printStackTrace();  
        }  
        //使用finally块来关闭输出流、输入流 
        finally {  
            try {  
                if (out != null) {
                    out.close();
                }  
                if ( in != null) {
                    in .close();
                }  
            } catch (IOException ex) {  
                ex.printStackTrace();  
            }  
        }  
        return result;  
    }