知识点

String字符串

/**
 * @author zhangyixuan
 * @version 2022.4
 * @date 2022/4/26 16:57
 */
public class StringTest {
    public static void main(String[] args) {
        String s1 = "ab";
        final String s2 = "b"; //编译器优化 常量折叠
        String s3 = "a" + s2;
        System.out.println(s1 == s3);//true
        final String s4 = getB(); //没有编译优化,编译时不会调用方法
        String s5 = "a" + s4;
        System.out.println(s1 == s5);//false
    }
    public static String getB() {
        return "b";
    }
}