在一個有關socket的程式中，客戶端出現了 socket is closed異常，我百思不得其解，並沒有關閉socket啊。

下面首先來分析一下這個異常出現的原因：該異常在客戶端和伺服器均可能發生。異常的原因是己方主動關閉了連線後（呼叫了Socket的close方法）再對網路連線進行讀寫操作。

而造成socket關閉常見的有以下兩種：
1、呼叫了.close()方法關閉socket
2、關閉了輸入輸出流

下面來看一下我的錯誤程式碼

 BufferedWriter bufferedWriter=null;
                try {
                    bufferedWriter = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream
 
()));

                } catch (IOException e) {
                    Log.d("Client","BufferedWriter出錯");
                    e.printStackTrace();
                }
                // 獲得EditTex的內容
                String text = mEditText.getText().toString();
                Log.e("Client","即將傳送的資訊為："+text);
 

                Log.e("Client","haha");
                try {
                    // 傳送資料
                    if (bufferedWriter != null) {
                        bufferedWriter.write(text+"\r\n");
                    }
                    bufferedWriter.flush();
                    bufferedWriter.close
 
();
                } catch (IOException e) {
                    Log.e("Client","傳送資料出錯");
                    e.printStackTrace();
                }
                Log.e("Client", "成功傳送資料");
                // 清空內容
                mEditText.setText("");
                Log.e("Client", "下面開始讀取資料");
                try {
                    BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream(),"UTF-8"));
                    Log.e("Client","完畢");
                    String s=in.readLine();
                    Log.e("Client",s);
                } catch (IOException e) {
                    Log.e("Client",e.getMessage());
                }

可以看到在用write()方法傳送完成後，又呼叫了bufferedWriter.close();正是因為這一行程式碼，導致socket closed。而下面BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream(),"UTF-8"));因此出現異常

那麼我們的解決方式是將bufferedWriter.close();下移到末尾處即可如下：

 BufferedWriter bufferedWriter=null;
                try {
                    bufferedWriter = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));

                } catch (IOException e) {
                    Log.d("Client","BufferedWriter出錯");
                    e.printStackTrace();
                }
                // 獲得EditTex的內容
                String text = mEditText.getText().toString();
                Log.e("Client","即將傳送的資訊為："+text);
                Log.e("Client","haha");
                try {
                    // 傳送資料
                    if (bufferedWriter != null) {
                        bufferedWriter.write(text+"\r\n");
                    }
                    bufferedWriter.flush();

                } catch (IOException e) {
                    Log.e("Client","傳送資料出錯");
                    e.printStackTrace();
                }
                Log.e("Client", "成功傳送資料");
                // 清空內容
                mEditText.setText("");
                Log.e("Client", "下面開始讀取資料");
                try {
                    BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream(),"UTF-8"));
                    Log.e("Client","完畢");
                    String s=in.readLine();
                    Log.e("Client",s);
                } catch (IOException e) {
                    Log.e("Client",e.getMessage());
                }