String的基础用法

java```
public class StringTest {
public static void main(String[] args) {
String str = "Hello Java";
System.out.println("定义字符串：" + str);
String str1 = "我是";
String str2 = "Java菜鸡";
String result = str1 + str2;
System.out.println("字符串拼接：" + result);
int length = str.length();
System.out.println("字符串长度：" + length);
String a = "123";
String b = "123";
System.out.println("字符串是否相等：" + a.equals(b));
String replaceStr = "Hello Java".replace("Java", "Java新手");
System.out.println("字符串替换：" + replaceStr);
}
}

  String 用来存储文字内容，直接用变量名 = "内容"定义最方便拼接字符串直接用+号比较字符串一定要用 equals ()，不要用 ==