JAVA的经典API排序与比较------JAVA

绝地灬酷狼 2024-03-22 14:42 168阅读 0赞

>     import java.util.Arrays;
>     import java.util.Comparator;
>     
>     public class ComparableTest
>     {
>         public static void main(String[] args)
>         {
>             String[] arr = new String[]{"Tom","Jerry","Rose","Jack","lUCY"};
>             Arrays.sort(arr,new Comparator()
>             {
>                 public int compare(Object o,Object o1)
>                 {
>                     if(o instanceof String && o1 instanceof String)
>                     {
>                         String s1 = (String)o;
>                         String s2 = (String)o1;
>                         return s1.compareTo(s2);
>                     }
>                     throw new RuntimeException("类型不匹配");
>                 }
>             });
>             for (int i = 0; i < arr.length; i++)
>             {
>                 System.out.println(arr[i]);
>             }
>             Project[] p = new Project[5];
>             p[0] = new Project("name",12);
>             p[1] = new Project("nce",1);
>             p[2] = new Project("nam",4);
>             p[3] = new Project("ace",124);
>             p[4] = new Project("ame",143);
>             Comparator comparator = new Comparator()
>             {
>                 public int compare(Object o,Object o1)
>                 {
>                     if(o instanceof Project && o1 instanceof  Project)
>                     {
>                         Project p = (Project)o;
>                         Project p1 = (Project)o1;
>                         return -Double.compare(p.getPrice(),p1.getPrice());
>                     }
>                     throw new RuntimeException("类型不匹配");
>                 }
>             };
>             Arrays.sort(p,comparator);
>             for (int i = 0; i < p.length; i++)
>             {
>                 System.out.println(p[i]);
>             }
>         }
>     }
>     
>     class Project implements Comparable
>     {
>         private String name;
>         private double price;
>     
>         public Project(String name, double price)
>         {
>             this.name = name;
>             this.price = price;
>         }
>     
>         @Override
>         public int compareTo(Object o)
>         {
>             if(o == this)
>             {
>                 return 0;
>             }
>             if(o instanceof Project)
>             {
>                 Project p = (Project)o;
>                 return Double.compare(this.price,p.price);
>             }
>             throw new RuntimeException("类型不匹配");
>         }
>     
>         public String getName() {
>             return name;
>         }
>     
>         public void setName(String name) {
>             this.name = name;
>         }
>     
>         public double getPrice() {
>             return price;
>         }
>     
>         public void setPrice(double price) {
>             this.price = price;
>         }
>     
>         @Override
>         public String toString() {
>             return "Project{" +
>                     "name='" + name + '\'' +
>                     ", price=" + price +
>                     '}';
>         }
>     }
> 
> import java.util.Arrays;  
> import java.util.Comparator;
> 
> public class ComparableTest  
> \{  
> public static void main(String\[\] args)  
> \{  
> String\[\] arr = new String\[\]\{"Tom","Jerry","Rose","Jack","lUCY"\};  
> Arrays.sort(arr,new Comparator()  
> \{  
> public int compare(Object o,Object o1)  
> \{  
> if(o instanceof String && o1 instanceof String)  
> \{  
> String s1 = (String)o;  
> String s2 = (String)o1;  
> return s1.compareTo(s2);  
> \}  
> throw new RuntimeException("类型不匹配");  
> \}  
> \});  
> for (int i = 0; i < arr.length; i++)  
> \{  
> System.out.println(arr\[i\]);  
> \}  
> Project\[\] p = new Project\[5\];  
> p\[0\] = new Project("name",12);  
> p\[1\] = new Project("nce",1);  
> p\[2\] = new Project("nam",4);  
> p\[3\] = new Project("ace",124);  
> p\[4\] = new Project("ame",143);  
> Comparator comparator = new Comparator()  
> \{  
> public int compare(Object o,Object o1)  
> \{  
> if(o instanceof Project && o1 instanceof Project)  
> \{  
> Project p = (Project)o;  
> Project p1 = (Project)o1;  
> return -Double.compare(p.getPrice(),p1.getPrice());  
> \}  
> throw new RuntimeException("类型不匹配");  
> \}  
> \};  
> Arrays.sort(p,comparator);  
> for (int i = 0; i < p.length; i++)  
> \{  
> System.out.println(p\[i\]);  
> \}  
> \}  
> \}
> 
> class Project implements Comparable  
> \{  
> private String name;  
> private double price;
> 
> public Project(String name, double price)  
> \{  
> this.name = name;  
> this.price = price;  
> \}
> 
> @Override  
> public int compareTo(Object o)  
> \{  
> if(o == this)  
> \{  
> return 0;  
> \}  
> if(o instanceof Project)  
> \{  
> Project p = (Project)o;  
> return Double.compare(this.price,p.price);  
> \}  
> throw new RuntimeException("类型不匹配");  
> \}
> 
> public String getName() \{  
> return name;  
> \}
> 
> public void setName(String name) \{  
> this.name = name;  
> \}
> 
> public double getPrice() \{  
> return price;  
> \}
> 
> public void setPrice(double price) \{  
> this.price = price;  
> \}
> 
> @Override  
> public String toString() \{  
> return "Project\{" +  
> "name='" + name + '\\'' +  
> ", price=" + price +  
> '\}';  
> \}  
> \}