StringBuffer

package com.jdk7.chapter5;
/**
 * 
 * @author Administrator
 *
 */
public class StringBufferTest {
    
    public static void findStr(StringBuffer sb, String dest){
        System.out.println("指定匹配开始的位置"+"("+sb+")"+".indexOf("+dest+")>"+sb.indexOf(dest));
        System.out.println("指定匹配开始的位置"+"("+sb+")"+".indexOf("+dest+", 4)>"+sb.indexOf(dest, 4));
        System.out.println("指定匹配结束的位置"+"("+sb+")"+".lastIndexOf("+dest+")>"+sb.lastIndexOf(dest));
        System.out.println("指定匹配结束的位置"+"("+sb+")"+".lastIndexOf("+dest+", 4)>"+sb.lastIndexOf(dest, 2));
    }
    
    public static void subStr(StringBuffer sb, int n, int m){
        System.out.println("从位置"+n+"开始截取"+"("+sb+").substring("+n+")>"+sb.substring(n));
        System.out.println("从位置"+n+"开始到"+m+"结束截取"+"("+sb+").substring("+n+", "+m+")>"+sb.substring(n, m));
    }
    
    public static void charAt(StringBuffer sb, int n){
        System.out.println("返回位置"+n+"的字符("+sb+").charAt("+n+")"+sb.charAt(n));
    }
    
    public static void append(){
        StringBuffer sb = new StringBuffer();
        sb.append("Hello").append(" ").append(new char[]{'w','o','r','l','d','!'}).append(3).append(true).append(6.44d)
        .append(78.445f);
        System.out.println("append>"+sb.toString());
    }
    
    public static void insert(StringBuffer sb, int n){
        System.out.println("("+sb+").insert>"+sb.insert(n, false).insert(n, 'b').insert(n, new char[]{'w','o','r','l','d','!'})
                .insert(n, 33.55d).insert(n, 7768.22f).insert(n, 66));
    }
    
    public static void delete(StringBuffer sb, int start, int end){
        System.out.println("("+sb+").delete("+start+", "+end+")>"+sb.delete(start, end));
        System.out.println("("+sb+").deleteCharAt("+start+")>"+sb.deleteCharAt(start));
    }
    
    public static void replace(StringBuffer sb, int start, int end, String str){
        System.out.println("("+sb+").replace("+start+", "+end+", "+str+")>"+sb.replace(start, end, str));
    }
    
    public static void reverse(StringBuffer sb){
        System.out.println("("+sb+").reverse()>"+sb.reverse());
        System.out.println("("+sb+").capacity()"+sb.capacity());
    }
    public static void main(String[] args) {
        StringBuffer sb = new StringBuffer("This is an object!");
        StringBufferTest.findStr(sb, "is");
        StringBufferTest.subStr(sb, 2, 10);
        StringBufferTest.charAt(sb, 6);
        StringBufferTest.append();
        StringBufferTest.insert(sb, 10);
        StringBufferTest.delete(sb, 2, 7);
        StringBufferTest.replace(sb, 2, 7, "hello");
        StringBufferTest.reverse(sb);
    }
}

执行结果：
指定匹配开始的位置(This is an object!).indexOf(is)>2
指定匹配开始的位置(This is an object!).indexOf(is, 4)>5
指定匹配结束的位置(This is an object!).lastIndexOf(is)>5
指定匹配结束的位置(This is an object!).lastIndexOf(is, 4)>2
从位置2开始截取(This is an object!).substring(2)>is is an object!
从位置2开始到10结束截取(This is an object!).substring(2, 10)>is is an
返回位置6的字符(This is an object!).charAt(6)s
append>Hello world!3true6.4478.445
(This is an object!).insert>This is an667768.2233.55world!bfalse object!
(This is an667768.2233.55world!bfalse object!).delete(2, 7)>Th an667768.2233.55world!bfalse object!
(Th an667768.2233.55world!bfalse object!).deleteCharAt(2)>Than667768.2233.55world!bfalse object!
(Than667768.2233.55world!bfalse object!).replace(2, 7, hello)>Thhello768.2233.55world!bfalse object!
(Thhello768.2233.55world!bfalse object!).reverse()>!tcejbo eslafb!dlrow55.3322.867ollehhT
(!tcejbo eslafb!dlrow55.3322.867ollehhT).capacity()70