java:常用类库api

 1 package com.vince;
 2 
 3 import java.util.Arrays;
 4 
 5 public class StringDemo2 {
 6 
 7     public static void main(String[] args) {
 8         
 9         String str = " fkwefwfa d6737383 ";
10         char c = str.charAt(1);
11         System.out.println(c);
12         
13         System.out.println(str.toCharArray());
14         char[] cs = {'a','b','c'};
15         String s1 = new String(cs);
16         
17         String s2 = new String(cs,0,1);
18         System.out.println(s2);
19         
20         System.out.println(Arrays.toString(str.getBytes()));
21         
22         System.out.println(str.replace('w', '*'));
23         System.out.println(str.replaceAll("\\d", "*"));
24         
25         System.out.println(str.substring(0, 4));
26         
27         System.out.println(Arrays.toString(str.split("d")));
28         
29         System.out.println(str.contains("a"));
30         
31         System.out.println(str.indexOf("f"));
32         System.out.println(str.lastIndexOf("f"));
33         System.out.println(str.isEmpty());
34         
35         System.out.println(str.length());
36         
37         System.out.println(str.trim());
38         
39         System.out.println(str.concat("*****"));
40         System.out.println(String.valueOf(10));
41     }
42 
43 }

View Code

 1 package com.vince;
 2 
 3 /**
 4  * 对象需要具备克隆功能：
 5  * 1、实现Cloneable接口,(标记接口)
 6  * 2、重写Object类中的clone方法
 7  * @author vince
 8  * @description
 9  */
10 public class Cat implements Cloneable{
11     private String name;
12     private int age;
13     public String getName() {
14         return name;
15     }
16     public void setName(String name) {
17         this.name = name;
18     }
19     public int getAge() {
20         return age;
21     }
22     public void setAge(int age) {
23         this.age = age;
24     }
25     public Cat(String name, int age) {
26         super();
27         this.name = name;
28         this.age = age;
29     }
30     public Cat() {
31         super();
32     }
33     //重写Object中的clone方法
34     @Override
35     protected Object clone() throws CloneNotSupportedException {
36         return super.clone();
37     }
38     @Override
39     public String toString() {
40         return "Cat [name=" + name + ", age=" + age + "]";
41     }
42     
43 }

Cat.java

 1 package com.vince;
 2 
 3 import java.io.IOException;
 4 
 5 public class Test {
 6 
 7     public static void main(String[] args) {
 8 
 9         Cat cat = new Cat("ίχίχΠʽ°Χ",2);
10         try {
11             Cat newCat = (Cat) cat.clone();
12             
13             
14             System.out.println("cat="+cat);
15             System.out.println("new cat="+newCat);
16             System.out.println(cat==newCat);
17         } catch (CloneNotSupportedException e) {
18             e.printStackTrace();
19         }
20         
21     }
22 
23 }

Test.java