java.util.List 常用总结

                      List list = new LinkedList();   
                       list = new ArrayList();         
            产生一个数组列对象并建立双向连表。
            连表分为单向连表和双向连表；单向连表就像：a只能到b，b不能到c；双向连表就像：a可以到b，b也可以到a。
            双向连表的作用是：可以在数列的任何地方插入数据。
                   list.add(0, "b");
            在数组列里添加数据，0表示数组里的下标，"b"表示添加的数据。
            建立双向连表后可以用 0 的变化来在数列的任何地方插入数据。
            如：在数组列的最后插入数据      list.add(list.size(), "any");
               
                      b = list.remove("b");                
                      b = list.remove(0);    
            删除数列中的数据，可以用以上两种方法来删除。一种是找对象，一种是找下标。
            2.排序：
                      String[] strArray = new String[] {"z", "a", "C"};
                   List list = Arrays.asList(strArray);
            一个数组列对象并且是和strArray的大小一样。
                  Collections.sort(list);
            按照ASCII的升序排序。
                      Collections.sort(list, String.CASE_INSENSITIVE_ORDER);
            按照英文字母顺序排序，忽略大小写。
               
                      Collections.sort(list, Collections.reverseOrder());
            按照ASCII的降序排序。
               
                       Collections.sort(list, String.CASE_INSENSITIVE_ORDER);
                      Collections.reverse(list);
            先按照英文字母顺序排序，然后再用降序排序。
            3.list的操作：
                      list1.retainAll(list2);
            只保留list1和list2中相同的部分（交集）？
                      list1.subList(newSize, list1.size()).clear();
            返回newSize到list1.size之间的部分。
            方法总结：
            list.add()：添加数据                                   list.remove()：删除数据
            Arrays.asList()：指定大小的列
            Collections.sort()：按ASCII升序排序         
            Collections.reverseOrder()和Collections.reverse()：按ASCII降序排序，区别在于参数
            list.addAll()：添加()所有数据                       
            list.removeAll()：删除()所有数据
            list.retainAll()：保留交集                             
            list.subList(size1, size2)： 返回size1到size2之间的数据
            eg1
            package lp;
            import java.util.*;
            import java.util.Map.Entry;
            public class mapTest {
            /**
               * @param args
               */
            public static void main(String[] args) {
               // TODO Auto-generated method stub
               String str[]={"apple","y","tig","zone"};
               Map map=new Hashtable();
             
               for(int i=0;i<str.length;i++){
                map.put(""+i, str[i]);
                System.out.println(map.size());
               }
               //map.clear();
             
               Set set=map.entrySet();
               Iterator t=set.iterator();
               while(t.hasNext()){
               Entry entry=(Entry)(t.next());
               System.out.println(entry.getValue());
               }
               }
            }
             
            eg2
            package lp;
            import java.text.SimpleDateFormat;
            import java.util.*;
            public class ListTest {
            public static void main(String [] args ){
               /*String a[]={"ads","cse","fawe","bd","zd","dsd"};
             
               List list = Arrays.asList(a);
               //list.add(0, "b");
               //list.add(a.length,"werw");
               //Collections.sort(list, Collections.reverseOrder());
                    Collections.sort(list, String.CASE_INSENSITIVE_ORDER);
                
               for(int i=0;i<a.length;i++){
                System.out.println(i+"   "+a[i]);
               }
             
               for(int i=0;i<a.length;i++){
                System.out.println(i+"   "+a[i]);
               } */
               //String[] strArray = new String[] {"z", "a", "C"};
                    // List list = Arrays.asList(strArray);
                    // Collections.sort(list);//根据元素自然顺序排序
                    //
                    // Collections.sort(list,
            String.CASE_INSENSITIVE_ORDER);//根据指定的字母方式排序   
                   
                   //   Collections.sort(list,
            Collections.reverseOrder());//根据反转自然顺序方式排序
                  
                   //   Collections.sort(list, String.CASE_INSENSITIVE_ORDER);
                   // 
                   //   Collections.reverse(list);//反转列表排序
                       
            /*
                  
                    
                      List    list=new    ArrayList();  
                      list.add("One");  
                      list.add("Two");  
                      list.add(new    Integer(123));  
                      list.add(new    Date());  
                      
                      System.out.println    (list.size());  
                      System.out.println    ((String)(list.get(0)));  
                      System.out.println    ((String)(list.get(1)));  
                      System.out.println    ((Integer)(list.get(2)));  
                      System.out.println    ((Date)(list.get(3)));  
                     
                   /*  
                    
                      ArrayList    h    =    new    ArrayList();  
                      h.add("1st");  
                      h.add("2st");  
                      h.add(new    Integer(3));  
                      h.add(new    Double(4));  
                      h.add(new    Integer(3));  
                      h.add("2st");
                      h.add("     ");
                      h.add(new Date());
                      display(h);  
                      }  
                      public    static    void    display(List    s)  
                      {  
                      System.out.println("    "+s);  
                      }
                    
                      */
                      /*
                       List list=new LinkedList();
                       list=new ArrayList();
                       list.add("boy");
                       list.add("apple");
                       list.add(0,"girl");
                       for(int i=0;i<list.size();i++){
                        System.out.println((String)(list.get(i)));
                        }
                       System.out.println("-------------------");
                       //list.remove("girl");
                       //list.add(new Double(23));
                       list.remove(0);
                       for(int i=0;i<list.size();i++){
                       System.out.println((String)(list.get(i)));
                       }
                     
                       list.add(new Date());
                       System.out.println((Date)(list.get(2)));
                     
                       SimpleDateFormat matter1=new
            SimpleDateFormat("'北京时间':yyyy年MM月dd日"+"     " +
                         ""+"HH时mm分ss秒");
                       System.out.println(matter1.format((Date)(list.get(2))));
                       */
               //int a[]={0,1,3,32,23,32,32,32,32};
               String a[]={"zone","apple","boy","girl","month","apple"};
               Set st=new TreeSet();
             
               for(int i=0;i<a.length;i++){
                st.add(new String(a[i]));
                System.out.print(" -_- "+st.size());
              
               }
                 st.add("china");
                 st.add("tig");
                 //st.remove("apple");
                   st.remove("apple");
                 //st.clear();
                // st.remove("tig");
               
                  
                       System.out.println();
                    
                      Iterator t=st.iterator();
                      //t.remove();
                      while(t.hasNext()){
                       System.out.print("****"+(String)t.next());
                      }
                     
            }
            }