StringBuffer

Posted 2020-10-25 celineluo

 1 package com.jdk7.chapter5;
 2 /**
 3  * 
 4  * @author Administrator
 5  *
 6  */
 7 public class StringBufferTest {
 8     
 9     public static void findStr(StringBuffer sb, String dest){
10         System.out.println("指定匹配开始的位置"+"("+sb+")"+".indexOf("+dest+")>"+sb.indexOf(dest));
11         System.out.println("指定匹配开始的位置"+"("+sb+")"+".indexOf("+dest+", 4)>"+sb.indexOf(dest, 4));
12         System.out.println("指定匹配结束的位置"+"("+sb+")"+".lastIndexOf("+dest+")>"+sb.lastIndexOf(dest));
13         System.out.println("指定匹配结束的位置"+"("+sb+")"+".lastIndexOf("+dest+", 4)>"+sb.lastIndexOf(dest, 2));
14     }
15     
16     public static void subStr(StringBuffer sb, int n, int m){
17         System.out.println("从位置"+n+"开始截取"+"("+sb+").substring("+n+")>"+sb.substring(n));
18         System.out.println("从位置"+n+"开始到"+m+"结束截取"+"("+sb+").substring("+n+", "+m+")>"+sb.substring(n, m));
19     }
20     
21     public static void charAt(StringBuffer sb, int n){
22         System.out.println("返回位置"+n+"的字符("+sb+").charAt("+n+")"+sb.charAt(n));
23     }
24     
25     public static void append(){
26         StringBuffer sb = new StringBuffer();
27         sb.append("Hello").append(" ").append(new char[]{‘w‘,‘o‘,‘r‘,‘l‘,‘d‘,‘!‘}).append(3).append(true).append(6.44d)
28         .append(78.445f);
29         System.out.println("append>"+sb.toString());
30     }
31     
32     public static void insert(StringBuffer sb, int n){
33         System.out.println("("+sb+").insert>"+sb.insert(n, false).insert(n, ‘b‘).insert(n, new char[]{‘w‘,‘o‘,‘r‘,‘l‘,‘d‘,‘!‘})
34                 .insert(n, 33.55d).insert(n, 7768.22f).insert(n, 66));
35     }
36     
37     public static void delete(StringBuffer sb, int start, int end){
38         System.out.println("("+sb+").delete("+start+", "+end+")>"+sb.delete(start, end));
39         System.out.println("("+sb+").deleteCharAt("+start+")>"+sb.deleteCharAt(start));
40     }
41     
42     public static void replace(StringBuffer sb, int start, int end, String str){
43         System.out.println("("+sb+").replace("+start+", "+end+", "+str+")>"+sb.replace(start, end, str));
44     }
45     
46     public static void reverse(StringBuffer sb){
47         System.out.println("("+sb+").reverse()>"+sb.reverse());
48         System.out.println("("+sb+").capacity()"+sb.capacity());
49     }
50     public static void main(String[] args) {
51         StringBuffer sb = new StringBuffer("This is an object!");
52         StringBufferTest.findStr(sb, "is");
53         StringBufferTest.subStr(sb, 2, 10);
54         StringBufferTest.charAt(sb, 6);
55         StringBufferTest.append();
56         StringBufferTest.insert(sb, 10);
57         StringBufferTest.delete(sb, 2, 7);
58         StringBufferTest.replace(sb, 2, 7, "hello");
59         StringBufferTest.reverse(sb);
60     }
61 }
62 
63 执行结果：
64 指定匹配开始的位置(This is an object!).indexOf(is)>2
65 指定匹配开始的位置(This is an object!).indexOf(is, 4)>5
66 指定匹配结束的位置(This is an object!).lastIndexOf(is)>5
67 指定匹配结束的位置(This is an object!).lastIndexOf(is, 4)>2
68 从位置2开始截取(This is an object!).substring(2)>is is an object!
69 从位置2开始到10结束截取(This is an object!).substring(2, 10)>is is an
70 返回位置6的字符(This is an object!).charAt(6)s
71 append>Hello world!3true6.4478.445
72 (This is an object!).insert>This is an667768.2233.55world!bfalse object!
73 (This is an667768.2233.55world!bfalse object!).delete(2, 7)>Th an667768.2233.55world!bfalse object!
74 (Th an667768.2233.55world!bfalse object!).deleteCharAt(2)>Than667768.2233.55world!bfalse object!
75 (Than667768.2233.55world!bfalse object!).replace(2, 7, hello)>Thhello768.2233.55world!bfalse object!
76 (Thhello768.2233.55world!bfalse object!).reverse()>!tcejbo eslafb!dlrow55.3322.867ollehhT
77 (!tcejbo eslafb!dlrow55.3322.867ollehhT).capacity()70