Java拾粹－Jemmy Walker

1.Java Util提供的原子計數器：

private static java.util.concurrent.atomic.AtomicInteger counter = new java.util.concurrent.atomic.AtomicInteger ();

int count = counter.get(); // return 計數

counter.incrementAndGet(); // 累加1

2.Resize array:

private int[] intArray = new int[] {2, 3};

org.apache.commons.lang.ArrayUtils.add(intArray, 5); // intArray = {2, 3, 5}

3.org.apache.commons.lang.StringUtils sample

StringUtils.isNotBlank();相當於如下：

if( variable != null && variable.length( ) > 0 && !variable.trim( ).equals("") ) {
// Do something
}

4.org.apache.commons.io.IOUtils sample:

 InputStream in = new URL( "http://jakarta.apache.org" ).openStream();
 try {
   System.out.println( IOUtils.toString( in ) );
 } finally {
   IOUtils.closeQuietly(in);
 }

等同於

 InputStream in = new URL( "http://jakarta.apache.org" ).openStream();
 try {
   InputStreamReader inR = new InputStreamReader( in );
   BufferedReader buf = new BufferedReader( inR );
   String line;
   while ( ( line = buf.readLine() ) != null ) {
     System.out.println( line );
   }
 } finally {
   in.close();
 }