Question

目的：用户输入姓名和年龄，并在结尾处打印一条消息：

＆＃34;姓名是年龄。＆＃34;

NameIsAge.java

function reload2(form)
            {   
                var val=form.loc.options[form.loc.options.selectedIndex].value;
                var val2 = form.category.options[form.category.options.selectedIndex].value;
                self.location='upload.php?category=' + val2 + '&loc=' + val;

            }

NameIsAgeLauncher.java

public class NameIsAge 
{
    static String userName;
    static int userAge;
    NameIsAge (String userName, int userAge)
    {
        userName = this.userName;
        userAge = this.userAge;

    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public int getUserAge() {
        return userAge;
    }
    public void setUserAge(int userAge) {
        this.userAge = userAge;
    }
    final void run(String[] args)
    {
        System.out.println(userName + " is " + userAge);
    }
}

这打印出来：

import java.util.Scanner;
public final class NameIsAgeLauncher {
    private NameIsAgeLauncher() 
    {
    }
    public static void main(String[] args) {
        String userName = null;
        int userAge = 0;
        Scanner stdIn = new Scanner(System.in);
        System.out.println("Enter your name: "); //Prompts user to enter name.
        NameIsAge.userName = stdIn.nextLine(); //Name from Practice should be equal to what the user enters.
        System.out.println("Enter your age: "); //Prompts user to enter name.
        NameIsAge.userAge = stdIn.nextInt(); //Name from Practice should be equal to what the user enters.
        NameIsAge blah = new NameIsAge(userName, userAge);

        NameIsAge halb = new NameIsAge ("Campbell", 97);
        halb.setUserName("Campbell");
        halb.setUserAge (97);
        System.out.println(blah.userName + " is " + blah.userAge + ".");
        System.out.println(halb.userName + " is " + halb.userAge + ".");
    }   
}

应打印出来：

Enter your name: 
dsf
Enter your age: 
32
Blah: Campbell is 97.
Halb: Campbell is 97.

Y是否设置halb change blah的值？

Answer 1

这是由静态修饰符引起的。

static String userName;
static int userAge;

删除静态关键字就是诀窍静态修改器表示它适用于所有实例顺便说一句。构造函数不好，应该是：

NameIsAge (String userName, int userAge)
{
    this.userName = userName;
    this.userAge = userAge;

}

包含整个代码：
尝试将局部变量用于辅助变量

import java.util.Scanner;
public final class NameIsAgeLauncher {
private NameIsAgeLauncher() 
{
}
public static void main(String[] args) {
    String userName = null;
    int userAge = 0;
    Scanner stdIn = new Scanner(System.in);
    System.out.println("Enter your name: "); //Prompts user to enter name.
    userName = stdIn.nextLine(); //Name from Practice should be equal to what the user enters.
    System.out.println("Enter your age: "); //Prompts user to enter name.
    userAge = stdIn.nextInt(); //Name from Practice should be equal to what the user enters.
    NameIsAge blah = new NameIsAge(userName, userAge);

    NameIsAge halb = new NameIsAge ("Campbell", 97);
    halb.setUserName("Campbell");
    halb.setUserAge (97);
    System.out.println(blah.userName + " is " + blah.userAge + ".");
    System.out.println(halb.userName + " is " + halb.userAge + ".");
}   
}

public class NameIsAge 
{
String userName;
int userAge;
NameIsAge (String userName, int userAge)
{
    this.userName = userName;
    this.userAge = userAge;

}
public String getUserName() {
    return userName;
}
public void setUserName(String userName) {
    this.userName = userName;
}
public int getUserAge() {
    return userAge;
}
public void setUserAge(int userAge) {
    this.userAge = userAge;
}
final void run(String[] args)
{
    System.out.println(userName + " is " + userAge);
}
}

不同的对象，同名变量应该有两个不同的值，但不是吗？

1 个答案: