给定字符串，实现大小写之间的转换

ps：java大小写之间转换练习

1.使用封装类型

Character.toUpperCase(temp)

的大小写转换函数

 public String convertString(String str) {
        StringBuffer sBuffer = new StringBuffer();
        for (int i = 0; i < str.length(); i++) {
            char temp = str.charAt(i);
            if (temp >= 'a' && temp <= 'z') {
                sBuffer.append(Character.toUpperCase(temp));
            } else {
                sBuffer.append(Character.toLowerCase(temp));
            }
        }
        return sBuffer.toString();
    }

2.使用ASCII表。小写比大写的值大32.

public String convertByAscii(String str) {
        char[] chs = str.toCharArray();
        for (int i = 0; i < chs.length; i++) {
            char temp = chs[i];
            if (temp <= 'a' && temp >= 'z') {//小写转大写
                chs[i] = (char) (temp - 32);//需要强制从char转为int
            } else if (temp <= 'A' && temp >= 'Z') {
                chs[i] = (char) (temp + 32);
            }
        }
        return String.valueOf(chs);
    }

https://blog.csdn.net/jiejinquanil/article/details/51166883 查看ascii表