遍历集合List

1.  //下标   
           for(int i = 0 ; i< list.size();i++){   
                  
               System.out.println(list.get(i));   
           }   
           //for- each   
           for(Object o:list){   
               System.out.println(o);   
           }   
           //迭代器   
           Iterator it = list.iterator();   
           while(it.hasNext()){   
               System.out.println(it.next());   
           }   
           //Object数组    
           Object o[];   
           o = list.toArray();   
           for(int i =  0 ; i <o.length;i++){   
               System.out.println(o[i]);   
           }   
   结果：[a,b,c,d]
   替换[ ] 
   o.toString().replaceAll("\\[", "").replaceAll("\\]", "")