这个测试客户端为何没有输出bb，我已经刷新了输出流，并清空了sb对象内容了，为什么还这样，如何解决

Question

 
```java
public class TestServer03 {
    public static void main(String[] args) throws IOException {
        ServerSocket ss = new ServerSocket(10086);

        Socket socket = ss.accept();

        InputStream is = socket.getInputStream();
        OutputStream os = socket.getOutputStream();
        StringBuilder sb = new StringBuilder();
        int ch;
        while ((ch = is.read()) != -1) {
            sb.append((char) ch);
            if (sb.toString().equals("aa")) {
                os.write(sb.toString().getBytes());
                os.flush(); // 刷新输出流
                sb.setLength(0);
            } else if (sb.toString().equals("bb")) {
                os.write(sb.toString().getBytes());
                os.flush(); // 刷新输出流
                sb.setLength(0);
            }
        }
        socket.close();
        ss.close();
    }
}


public class TestClient03 {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("127.0.0.1", 10086);

        OutputStream os = socket.getOutputStream();
        os.write("aa!".getBytes());
        os.flush(); // 刷新输出流

        InputStream is = socket.getInputStream();
        int ch;
        while ((ch = is.read()) != -1) {
            System.out.print((char) ch);
        }
        System.out.println();

        os.write("bb".getBytes());
        os.flush(); // 刷新输出流

        while ((ch = is.read()) != -1) {
            System.out.print((char) ch);
        }

        socket.close();
    }
}

为什么客户端没有输出bb

Answer 1

收到aa时会立即将其发送回客户端，然后清空StringBuilder对象，而不会继续判断是否收到bb。所以当客户端发送bb时，服务器端不会输出