Java 电子邮件验证中的编译器错误

Question

我在 JAVA 中遇到电子邮件验证时遇到问题（这是新手）不断收到这些错误，并对原因感到困惑。我应该收到人员的电子邮件，检查它是否设定标准（由我的教授），然后获取有关测试的信息。当我检查电子邮件时，如果有错误，我应该显示错误。

错误

N:ProgrammingJavaHomeworkEmailAndGrade.java:29: illegal start of expression
    private static boolean validEmail(sEmail);
    ^
N:ProgrammingJavaHomeworkEmailAndGrade.java:29: illegal start of expression
    private static boolean validEmail(sEmail);
            ^
N:ProgrammingJavaHomeworkEmailAndGrade.java:29: ';' expected
    private static boolean validEmail(sEmail);
                  ^
3 errors

法典

public class EmailAndGrade
{
    public static void main(String[] args)
    {
        //Variables
        String sEmail, sError, sTest;
        int iTest;
        char cGrade;
        sEmail = JOptionPane.showInputDialog("Enter your email: ");

        private static boolean validEmail(sEmail);
                {
                // editing to make requirements listed
                // return email.matches("[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}");
                return email.matches("[A-Z0-9]{7}+@[springfieldcollege]+\.[edu]");
                };
        sError = "One or More Errors with the Input Email.n" +
                 "Email is Empty.n" +
                 "Email must be less than 30 characters.n" +
                 "Must end in: @springfieldcollege.edu.n" +
                 "Can only have one @.n" +
                 "Must start with A through Z or a through z.n" +
                 "Can not have: # $ % & ,n ";
        sTest = JOptionPane.showInptDialog("Enter Test Grade: ");
        iTest = Integer.parseInt(sTest);
        System.exit(0);

    }
    /*
        void checkEmails()
        {
            for(String email : emailAddresses) {
            if(validEmail(email)) {
                 // it's a good email - do something good with it
            }
            else {
                 // it's a bad email - do something... bad to it? sounds dirty...
                JOptionPane.showMessageDialog(null,
                                              sError,
                                              "Email Error - Killian O'Brien",
                                              JOptionPane.INFORMATION_MESSAGE);
                }
    }*/

}

*编辑

好的，现在我有这个代码了

package com.mkyong.regex;
import javax.swing.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class EmailAndGrade
{
public static void main(String[] args)
{
    //Variables
    String sEmail, sError, sTest;
    int iTest;
    char cGrade;
    sEmail = JOptionPane.showInputDialog("Enter your email: ");

    sError = "One or More Errors with the Input Email.n" +
             "Email is Empty.n" +
             "Email must be less than 30 characters.n" +
             "Must end in: @springfieldcollege.edu.n" +
             "Can only have one @.n" +
             "Must start with A through Z or a through z.n" +
             "Can not have: # $ % & ,n ";
    sTest = JOptionPane.showInptDialog("Enter Test Grade: ");
    iTest = Integer.parseInt(sTest);
    System.exit(0);

}
public static boolean validEmail(String sEmail){
        return email.matches("[A-Z0-9]{7}+@[springfieldcollege]+\.[edu]");
    }
public static void checkEmails(){
    for(String sEemail : emailAddresses) {
        if(validEmail(email)) {
            // it's a good email - do something good with it
        }
        else {
            // it's a bad email - do something... bad to it? sounds dirty...
            JOptionPane.showMessageDialog(null,
                                          sError,
                                          "Email Error - Killian O'Brien",
                                          JOptionPane.INFORMATION_MESSAGE);
                 }
             }
             }
}

我现在得到这些

N:ProgrammingJavaHomeworkEmailAndGrade.java:37: cannot find symbol
symbol  : method showInptDialog(java.lang.String)
location: class javax.swing.JOptionPane
        sTest = JOptionPane.showInptDialog("Enter Test Grade: ");
                           ^
N:ProgrammingJavaHomeworkEmailAndGrade.java:47: cannot find symbol
symbol  : variable emailAddresses
location: class com.mkyong.regex.EmailAndGrade
        for(String email : emailAddresses) {
                           ^
N:ProgrammingJavaHomeworkEmailAndGrade.java:54: cannot find symbol
symbol  : variable sError
location: class com.mkyong.regex.EmailAndGrade
                                              sError,
                                              ^
N:ProgrammingJavaHomeworkEmailAndGrade.java:63: cannot find symbol
symbol  : variable email
location: class com.mkyong.regex.EmailAndGrade
        return email.matches("[A-Z0-9]{7}+@[springfieldcollege]+\.[edu]");
               ^
4 errors

当我输入这个时，我意识到我只有一堆未声明的变量。这对吗？

Answer 1

您正在另一个方法main中实现方法validEmail，这是不允许的。将下面的方法移出 main 函数（就在最后一行之前（在类右大括号 } 之前））。此外，您在方法实现中的两个位置（第一行结束和最后一行结束）使用额外的分号。删除分号 ; 。最后，在方法签名中添加参数类型类（字符串）。更新后的方法应如下所示：

    private static boolean validEmail(String sEmail){
      // editing to make requirements listed
      // return email.matches("[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}");
      return email.matches("[A-Z0-9]{7}+@[springfieldcollege]+\.[edu]");
    }

Answer 2

不能以内联方式声明函数。 将您的validEmail()声明移出main()。 同样的情况是，分号也应从方法声明的末尾删除。