字符串相关代码

public class CH05_1 {
public static void main(String[] args) {
Scanner input=new Scanner(System.in);
//第一种
String s = "helloworld";
System.out.println(s.length());
//第二种
String s1 = new String();
s1="helloworld";
System.out.println(s1.length());
//第三种
String s2 = new String("helloworld");
System.out.println(s2.length());

System.out.println("请输入用户名");
@SuppressWarnings("unused")
String name = input.next();
System.out.println("请输入密码");
String paw = input.next();
if(paw.length()<6){
System.out.println("密码长度小于六位，输入失败");
}else{
System.out.println("密码输入正确，注册成功");
}
input.close();

String s3 = "123";
String s4 = "123";
System.out.println(s3==s4);
String s5 = new String("12345");
String s6 = new String("12345");
System.out.println(s5==s6);
System.out.println(s5.equals(s6));
//直接使用equalsignore比较
String s7 = "tom";
String s8 = "Tom";
System.out.println(s7.equals(s8));
System.out.println(s7.equalsIgnoreCase(s8));
System.out.println(s7.toLowerCase().equals(s8.toLowerCase()));
System.out.println(s7.toUpperCase().equals(s8.toUpperCase()));
//全部转为大写之后再比较
String s9 = s7.toUpperCase();
String s10 = s8.toUpperCase();
System.out.println(s9.equals(s10));
//全部转为小写再比较
String s11 = s7.toLowerCase();
String s12 = s8.toLowerCase();
System.out.println(s11.equals(s12));
}