String

String 转 String数组：

        String str = "hello";
        String[] split = str.split("");

String 首字母转大写：

public static String captureName(String name) {
   //   name = name.substring(0, 1).toUpperCase() + name.substring(1);
   //   return  name;
        char[] cs=name.toCharArray();
        cs[0]-=32;
        return String.valueOf(cs);
 }

字符串替换：

    public static void main(String[] args) {
        String str = "hello %s";
        String format = String.format(str, "world");
        System.out.println(format);
    }

输出：

Connected to the target VM, address: '127.0.0.1:50025', transport: 'socket'
hello world
Disconnected from the target VM, address: '127.0.0.1:50025', transport: 'socket'

Process finished with exit code 0