IF 语句在 for 循环中不能很好地工作

Question

在下面的代码中，我想让用户在搜索框中输入可用的学生 ID 之一，然后如果学生 ID 有效，将出现一个简单的消息框，其中包含可用的学生 ID。

情况 1：当我在搜索框中输入 212 时，效果很好。

情况2：当我输入215或219或214（不是212）时，它会跳转到“未找到”消息框，再尝试两次后，我会收到一个包含已找到学生ID的消息框。

问题为什么我第一次输入215或219或214时没有找到消息框，但输入212时却可以正常工作？这个 for 循环或 IF 语句有什么问题？为什么当我输入215时，它会忽略第一次和第二次然后显示找到的消息框？

import javax.swing.*;

static int[] studentID = {212,214,215,219};

public static void main(String[] args) {

    search();

    System.exit(0);

}

public static void search(){

    for(int i = 0;i < studentID.length;i++){

        search = JOptionPane.showInputDialog(null,"Enter a student ID");

        if(studentID[i] == Integer.parseInt(search)){

            JOptionPane.showMessageDialog(null, studentID[i]);

            break;

        }else{

            JOptionPane.showMessageDialog(null,"NOT FOUND!!!");

        }

    }

}

Answer 1

循环应该在读取输入之后，并且“NOT FOUND”消息应该在循环之后：public static void search(){&nbsp; &nbsp; search = JOptionPane.showInputDialog(null,"Enter a student ID");&nbsp; &nbsp; for(int i = 0;i < studentID.length;i++){&nbsp; &nbsp; &nbsp; &nbsp; if(studentID[i] == Integer.parseInt(search)){&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; JOptionPane.showMessageDialog(null, studentID[i]);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return;&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }&nbsp; &nbsp; OptionPane.showMessageDialog(null,"NOT FOUND!!!");}如果要执行多次搜索，则应search()多次调用该方法。

Answer 2

import javax.swing.*;public class Stackoverflow1 {&nbsp; &nbsp; static int[] studentID = {212,214,215,219};&nbsp; &nbsp; public static void main(String[] args) {&nbsp; &nbsp; &nbsp; &nbsp; search();&nbsp; &nbsp; &nbsp; &nbsp; System.exit(0);&nbsp; &nbsp; }&nbsp; &nbsp; public static void search(){&nbsp; &nbsp; &nbsp; &nbsp; String enter_a_student_id = JOptionPane.showInputDialog(null, "Enter a student ID");&nbsp; &nbsp; &nbsp; &nbsp; for(int i = 0;i < studentID.length;i++){&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; if(studentID[i] == Integer.parseInt(enter_a_student_id)){&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; JOptionPane.showMessageDialog(null, studentID[i]);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; System.exit(0);&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; JOptionPane.showMessageDialog(null,"NOT FOUND!!!");&nbsp; &nbsp; }}