java.util.logging.FileHandler

java.util.logging.FileHandler

java自带的日志功能，FileHandler可以写日志到文件系统，并且自己维护日志的增删，比c++不知道强多少

FileHandler(filename,2,2); 测试时只写2k，并只保留2个文件：

 import java.io.IOException;
 import java.util.logging.FileHandler;
 import java.util.logging.Logger; // <= (1)

 public class Loggertest {

     private static Logger log = Logger.getLogger(Loggertest.class.getSimpleName());// <= (2)
     public void sub()
     {
         String filename="D:\\test\\1.txt";
         FileHandler fh;
         try {
             fh = new FileHandler(filename,2,2);
             log.addHandler(fh);

             log.info("  1String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  2String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  3String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  4String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  5String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  6String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  7String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  8String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  9String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  10String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  11String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  12String userDir = System.getenv(\"USERPROFILE\");");// <= (3)

             log.info("  13String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  14String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  15String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  16String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  17String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  18String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  19String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  20String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  21String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
             log.info("  22String userDir = System.getenv(\"USERPROFILE\");");// <= (3)
         } catch (SecurityException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         } catch (IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
     }

     public static void main(String[] args)
     {
         Loggertest logWorld = new Loggertest();
         logWorld.sub();
     }
 }