StringBuffer 方法

    //append   字符串拼接的方法
        StringBuffer stringBuffer = new StringBuffer("我爱中国！");
        StringBuffer stringBuffer2 = stringBuffer.append("我爱故乡！");
        System.out.println(stringBuffer2);
        //charAt  获取指定索引处的字符 
        StringBuffer stringBuffer3 = new StringBuffer("I LOVE CODE");
        char c = stringBuffer3.charAt(2); 
        System.out.println(c);
        //setCharAt  将指定索引处的字符替换为相应的字符
        StringBuffer stringBuffer4 = new StringBuffer("I LOVE CODE");
        stringBuffer4.setCharAt(0, 'Y');
        System.out.println(stringBuffer4);
        //insert 往指定的位置插入相应的字符
        StringBuffer stringBuffer5 = new StringBuffer("12345678");
        for (int i = stringBuffer5.length()-3; i > 0 ; i = i-3) {
            stringBuffer5.insert(i, ',');
        }
        System.out.println(stringBuffer5);
        //delete   删除从指定位置开始   到指定位置结束的字符串
        StringBuffer stringBuffer6 = new StringBuffer("My Name Is Not ChenChuanYin");
        stringBuffer6.delete(11, 15);
        System.out.println(stringBuffer6);
        //replace 将指定索引位置开始位置到结束索引位置结束之间的字符转   用相应的字符串替换
        StringBuffer stringBuffer7 = new StringBuffer("My SEX IS WOMAN");
        stringBuffer7.replace(10, 15, "MAN");
        System.out.println(stringBuffer7);
　　　　
　　　　//reverse  将字符串倒序输出
　　　　StringBuffer stringBuffer8 = new StringBuffer("12321");
　　　　StringBuffer stringBuffer9 = stringBuffer8.reverse();
　　　　System.out.println(stringBuffer9);