1.如果字串最後一位有值，則沒有區別，

2.若干最後n位都是切割符，split(" ")不會繼續切分，split(" ", -1)會繼續切分

String line = "a b  c         ";  
  String [] tmp = line.split(" ");  
  System.out.println(tmp.length+"------");  
  for(int i=0;i<tmp.length;i++){  
      System.out.println(i+"="+tmp[i]);  
  }  
    
  String [] items = line.split(" ",-1);  
  System.out.println(items.length+"========");  
  for(int i=0;i<items.length;i++){  
      System.out.println(i+"="+items[i]);  
  }  
 

4------
0=a
1=b
2=
3=c
13========
0=a
1=b
2=
3=c
4=
5=
6=
7=
8=
9=
10=
11=
12=

[java] view plain copy
String line = "a b  c         d";  
  String [] tmp = line.split(" ");  
  System.out.println(tmp.length+"------");  
  for(int i=0;i<tmp.length;i++){  
      System.out.println(i+"="+tmp[i]);  
  }  
    
  String [] items = line.split(" ",-1);  
  System.out.println(items.length+"========");  
  for(int i=0;i<items.length;i++){  
      System.out.println(i+"="+items[i]);  
  }  
 

13------
0=a
1=b
2=
3=c
4=
5=
6=
7=
8=
9=
10=
11=
12=d
13========
0=a
1=b
2=
3=c
4=
5=
6=
7=
8=
9=
10=
11=
12=d