尝试运行代码时，我收到“没有主方法错误”

Question

我对 Java 很陌生，在我的课程中学到的东西不多。每次我尝试运行我的代码时，都会被告知我没有 main 方法。然而，我认为 公共无效主要（字符串[]参数）{ 声明 main 方法，它位于我的代码的底部。任何人都可以帮助修改代码以使其运行吗？

package Java2;
import java.util.Date;

public class tenpoint01 {

public class Time {
    private int hour;
    private int minute;
    private int second;
    public Time() {
    this(System.currentTimeMillis());
}

public Time(long elapsed) {
    Date date = new Date(elapsed);
    this.hour = date.getHours();
    this.minute = date.getMinutes();
    this.second = date.getSeconds();
}

public Time(int hour, int minute, int second) {
    this.hour = hour;
    this.minute = minute;
    this.second = second;
}

private void setTime(long elapsedTime) {
    Date date = new Date(elapsedTime);
    this.hour = date.getHours();
    this.minute = date.getMinutes();
    this.second = date.getSeconds();
}

public int getHour() {
    return hour;
}

public int getMinute() {
    return minute;
}

public int getSecond() {
    return second;
}

@Override
public String toString() {
    return hour + ":" + minute + ":" + second;
}
/**
* @param args the command line arguments
*/
public void main(String[] args) {
    Time time = new Time();
    Time time2 = new Time(555550000);
    System.out.println(time);
    System.out.println(time2);
}
}
}

Answer 1

改变

public void main(String[] args) {

到

public static void main(String[] args) {

导致

package java2;

import java.util.Date;

public class tenpoint01 {

    public class Time {
        private int hour;
        private int minute;
        private int second;

        public Time() {
            this(System.currentTimeMillis());
        }

        public Time(long elapsed) {
            Date date = new Date(elapsed);
            this.hour = date.getHours();
            this.minute = date.getMinutes();
            this.second = date.getSeconds();
        }

        public Time(int hour, int minute, int second) {
            this.hour = hour;
            this.minute = minute;
            this.second = second;
        }

        private void setTime(long elapsedTime) {
            Date date = new Date(elapsedTime);
            this.hour = date.getHours();
            this.minute = date.getMinutes();
            this.second = date.getSeconds();
        }

        public int getHour() {
            return hour;
        }

        public int getMinute() {
            return minute;
        }

        public int getSecond() {
            return second;
        }

        @Override
        public String toString() {
            return hour + ":" + minute + ":" + second;
        }

        /**
         * @param args the command line arguments
         */
        public void main(String[] args) {
            Time time = new Time();
            Time time2 = new Time(555550000);
            System.out.println(time);
            System.out.println(time2);
        }
    }
}

运行上述结果

16
4
4
4
4
0

正在打印

应该这样做

Answer 2

main方法的签名不正确你缺少static关键字，main方法应该是：

public static void main(String[] args) {
       ^^^^^^
    // your code here
}

---

因为您使用的是Netbeans（现在很智能），您只需输入public 并按Ctrl + Enter 即可看到main 方法。或者只需输入psvm，然后输入tab，更多详情请点击此处：

• How to insert main method in Netbeans (shortcut)

Answer 3

您应该在主方法中添加“静态”关键字

要执行你目前拥有的，应该是：

public static void main(String[] args) {
 Time time = new Time();
 Time time2 = new Time(555550000);
 System.out.println(time);
 System.out.println(time2);

}