// String--->StringBuffter構造傳值
// StringBuffter 一種創建方式 new
StringBuffer buffer = new StringBuffer("123");
System.out.println(buffer);
// StringBuffter-->String toString()
String str = buffer.toString();
System.out.println(str);
// String +
// StringBuffter append();
str = str + "456";
buffer.append("56789").append(123321).append(12);
System.out.println("str:" + str);
System.out.println(buffer);
// 插入
buffer.insert(3, 9);// 參數1 是下標,參數2是下標
System.out.println("插入後的:" + buffer);
int i = buffer.indexOf("9");
System.out.println("9的位置在:" + i + "第幾位");
// 截取
String Str = buffer.substring(0, 5);
System.out.println("截取的字符串爲:" + Str);
// 替換
StringBuffer replace = buffer.replace(2, 4, "123213");
System.out.println("替換之後的buffer:" + replace);
// 反轉
StringBuffer reverse = buffer.reverse();
System.out.println("翻轉爲:"+reverse);
}