• append(String str)/append(Char c)：字符串连接

    System.out.println("StringBuilder:"+strB.append("ch").append("111").append('c'));
//return "StringBuilder:ch111c"

  • toString()：返回一个与构建起或缓冲器内容相同的字符串

    System.out.println("String:"+strB.toString());
//return "String:ch111c"

  • 3、appendcodePoint(int cp)：追加一个代码点，并将其转换为一个或两个代码单元并返回this

    System.out.println("StringBuilder.appendCodePoint:"+strB.appendCodePoint(2));
//return "StringBuilder.appendCodePoint:ch111c"

  • 4、setCharAt(int i, char c)：将第 i 个代码单元设置为 c（可以理解为替换）

    strB.setCharAt(2, 'd');
System.out.println("StringBuilder.setCharAt:" + strB);
//return "StringBuilder.setCharAt:chd11c"

  • 5、insert(int offset, String str)/insert(int offset, Char c)：在指定位置之前插入字符(串)

    System.out.println("StringBuilder.insertString:"+ strB.insert(2, "LS"));
//return "StringBuilder.insertString:chLSd11c"

  • 6、delete(int startIndex,int endIndex)：删除起始位置（含）到结尾位置（不含）之间的字符串

    System.out.println("StringBuilder.delete:"+ strB.delete(2, 4));
//return "StringBuilder.delete:chSd11c"