StringBuffer类

　　

父类:java.lang.Object  

java.lang.StringBuffer
1.StringBuffer构造方法

1>StringBuffer()
　　构造一个不带字符的字符缓冲区,其初始容量为16个字符
2>StringBuffer(CharSequence seq)
　　构造一个字符串缓冲区包含与接口CharSequence相同的字符
　　接口CharSequence的实现类包括String类/StringBuffer类/StringBuilder类
　　因此StringBuffer(String value)是可以的;
3>StringBuffer(int capacity)
　　指定初始容量的字符串缓冲区
4>StringBuffer(String str)//见2>

2.StringBuffer特有方法
1>public StringBuffer append(int x)//(char value)//(boolean value)
　　

      1.StringBuffer leo9257 = new StringBuffer("nanjing.");

　　2.System.out.println(leo9257);//nanjing.

　　3.leo9257.append("guiyang");

　　4.System.out.println(leo9257);//nanjing.guiyang

　　5.leo9257.append(true).append('@').append(2009);

　　6.System.out.println(leo9257);//nanjing.guiyangtrue@2009

2>public StringBuffer insert(int off,String str)

　　

   1.StringBuffer leo9257 = new StringBuffer("nanjing.");


　　2.leo9257.insert(6, "guiyang");//nanjinguiyangg.在索引出插入


　　3.leo9257.insert(8, "guiyang");//nanjing.guiyang 

3>public StringBuffer delete(int start,int end)

　　

    1.StringBuffer leo9257 = new StringBuffer("nanjing.guiyang2009-201*");

　　2.leo9257.delete(19,leo9257.length());//nanjing.guiyang2009

4>public StringBuffer reserve()

　　1.StringBuffer leo9257 = new StringBuffer("nanjing.guiyang2009-201*");

　　2.leo9257.reverse();//*102-9002gnayiug.gnijnan

5>public StringBuffer replace(int Start,int end,String str)
　　

    1.StringBuffer leo9257 = new StringBuffer("nanjing...guiyang2009");

　　 2.leo9257.replace(7, 9, "pukou");//nanjingpukou.guiyang2009
    

6.eg

/*
 *
 *将一句话的首字母都转为大写
 *leo9257 is the man who stayed in nanjing for nearly nine years. 
 */

public class UpperCaseDeom {
    public static void main(String[] args) {
        String s = "leo9257 is the man who stayed in Nanjing for nearly 9 years.";
        
        StringBuffer ns = new StringBuffer();
        
        String[] words = s.split(" ");
        
        for (int i = 0; i < words.length; i++) {
            String s0 = words[i].substring(0,1).toUpperCase()+words[i].substring(1);
            ns.append(s0+" ");
        }
        System.out.println(ns);
    }
}