Reading inputStream using BufferedReader readLine is too slow

Question

I am using following code   BufferedReader in   new BufferedReader new InputStreamReader conn getInputStream      String line   null   StringBuilder responseData   new StringBuilder    while  line   in readLine       null        responseData append line       But it is taking more than 12 sec to read 200 line   Please help

User · Answer

I strongly suspect that s because of the network connection or the web server you re talking to - it s not BufferedReader s fault  Try measuring this   InputStream stream   conn getInputStream    byte   buffer   new byte 1000      Start timing while  stream read buffer   gt  0         End timing   I think you ll find it s almost exactly the same time as when you re parsing the text   Note that you should also give InputStreamReader an appropriate encoding - the platform default encoding is almost certainly not what you should be using

User · Answer

I have a longer test to try   This takes an average of 160 ns to read each line as add it to a List  Which is likely to be what you intended as dropping the newlines is not very useful   public static void main String    args  throws IOException       final int runs   5   1000   1000       final ServerSocket ss   new ServerSocket 0       new Thread new Runnable              Override         public void run                 try                   Socket serverConn   ss accept                    String line    Hello World  n                   BufferedWriter br   new BufferedWriter new OutputStreamWriter serverConn getOutputStream                      for  int count   0  count  lt  runs  count                        br write line                   serverConn close                  catch  IOException e                    e printStackTrace                                   start         Socket conn   new Socket  localhost   ss getLocalPort          long start   System nanoTime        BufferedReader in   new BufferedReader new InputStreamReader conn getInputStream          String line       List lt String gt  responseData   new ArrayList lt String gt         while   line   in readLine       null            responseData add line             long time   System nanoTime   - start      System out println  Average time to read a line was     time   runs     ns         conn close        ss close        prints  Average time to read a line was 158 ns    If you want to build a StringBuilder  keeping newlines I would suggets the following approach   Reader r   new InputStreamReader conn getInputStream     String line   StringBuilder sb   new StringBuilder    char   chars   new char 4 1024   int len  while  len   r read chars   gt  0        sb append chars  0  len       Still prints  Average time to read a line was 159 ns    In both cases  the speed is limited by the sender not the receiver   By optimising the sender  I got this timing down to 105 ns per line

[java] Reading inputStream using BufferedReader.readLine() is too slow

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