用Java集合中的Collections.sort方法对list排序的两种方法

最简单的就是上面红色的字。。。。。。。。。。。

默认为升序，将。return

return

就成倒序的了。。

用Collections.sort方法对list排序有两种方法 
第一种是list中的对象实现Comparable接口，如下： 

代码:

Java代码

/**
* 根据order对User排序
*/
public class User implements
private
private
public
return
     }   
public void
this.name = name;   
     }   
public
return
     }   
public void
this.order = order;   
     }   
public int
return this.getOrder().compareTo(arg0.getOrder());   
     }   
}   
  
  
  
public class
public static void
new
"a"); user1.setOrder(1);   
new User(); user2.setName("b");   
2);   
new
//此处add user2再add user1 
         list.add(user2); list.add(user1);   
         Collections.sort(list);   
for(User u : list){   
             System.out.println(u.getName());   
         }   
     }   
}

<span style="">/**
* 根据order对User排序
*/
public class User implements
private
private
public
return
    }  
public void
this.name = name;  
    }  
public
return
    }  
public void
this.order = order;  
    }  
public int
return this.getOrder().compareTo(arg0.getOrder());  
    }  
}  
  
public class
public static void
new
"a"); user1.setOrder(1);   
new User(); user2.setName("b");  
2);   
new
//此处add user2再add user1 
        list.add(user2); list.add(user1);   
        Collections.sort(list);   
for(User u : list){   
            System.out.println(u.getName());   
        }   
    }   
}  
  
</span>

输出结果如下 

a 

b 

第二种方法是根据Collections.sort重载方法来实现，例如： 

代码:

Java代码

/**
* 根据order对User排序 */
public class
//此处无需实现Comparable接口 
private
private
public
return
     }   
public void
this.name = name;   
     }   
public
return
     }   
public void
this.order = order;   
     }   
}   
  
  
  
  
public class
public static void
new
"a");   
1);   
new
"b");   
2);   
new
        list.add(user2);   
        list.add(user1);   
        Collections.sort(list,new Comparator<User>(){   
public int
return
            }   
        });   
for(User u : list){   
           System.out.println(u.getName());   
        }   
     }   
}