Java 当我的编译器告诉我I';我在使用不安全或未经检查的操作?
我的程序编译得很好,但我的控制台显示了以下内容:Java 当我的编译器告诉我I';我在使用不安全或未经检查的操作?,java,compiler-construction,unchecked,Java,Compiler Construction,Unchecked,我的程序编译得很好,但我的控制台显示了以下内容: ----jGRASP exec: javac -g CreditGraphics.java Note: CreditGraphics.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details. ----jGRASP: operation complete. 首先,是什么使操作不安全?一个过程怎么能被“取消检查”?
----jGRASP exec: javac -g CreditGraphics.java
Note: CreditGraphics.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
----jGRASP: operation complete.
首先,是什么使操作不安全?一个过程怎么能被“取消检查”?“使用-Xlint重新编译”是什么意思?我使用的是jGrasp,我不确定这是一个按钮还是某种命令?我想看看细节。它没有指定什么是不安全的或未检查的,但下面是我的代码:
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import java.util.Scanner;
import java.util.Arrays;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.*;
import java.util.*;
import java.io.*;
import javax.mail.*;
import javax.mail.event.*;
import javax.mail.internet.*;
import javax.activation.*;
import java.util.Properties;
import javax.mail.Header;
import java.util.Enumeration;
import java.util.Properties;
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.applet.Applet;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.JApplet;
import javax.mail.Authenticator;
import javax.mail.Folder;
import javax.mail.Header;
import javax.mail.Message;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.URLName;
import java.beans.*;
import java.util.ArrayList;
import javax.swing.SwingUtilities;
import javax.swing.filechooser.*;
import java.util.Scanner;
import java.awt.image.*;
import java.io.*;
import java.net.URL;
import javax.imageio.*;
import javax.swing.Timer;
public class CreditGraphics {
//first screen variables
public String cardNum;
public JFrame frame;
public JPanel panel;
public JLabel label;
public JTextField text;
public String cardType = "";
public String carddigits;
public boolean cardValid;
public int length;
public String[] cardTypes;
public JComboBox cardTypesDD;
public static ArrayList<Integer> holdDigits = new ArrayList<Integer>();
public static ArrayList<String> holdDigitsChar = new ArrayList<String>();
public static int[] checkDigits;
public static int checkSum = 0;
//second screen variables in verifyScreen;
public JFrame vframe;
public JPanel vpanel;
public JLabel titlelabel;
public GridBagConstraints grid;
public JLabel namelabel;
public JTextField namefield;
public CreditGraphics() {
frame = new JFrame("MES Banking App");
panel = new JPanel();
label = new JLabel();
cardTypes = new String[4];
cardTypes[0] = "Visa";
cardTypes[1] = "American Express";
cardTypes[2] = "Master Card";
cardTypes[3] = "";
cardTypesDD = new JComboBox(cardTypes);
cardTypesDD.setSelectedIndex(3);
text = new JTextField(16);
panel.add(label);
panel.add(cardTypesDD);
panel.add(text);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel.setPreferredSize(new Dimension(500, 500));
frame.getContentPane().add(panel);
frame.pack();
frame.setVisible(true);
label.setText("<html>Please enter your credit card <br> 'Master Card' 'Visa' or 'American Express'</html>");
text.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
//after CC type is entered, prompt user to enter digits
carddigits = text.getText();//gets credit card number from jtextfield
length = carddigits.length();//sets length of card
validateCard(); //uses credit card number and length to determine if it matches up to brand
//below returns if card is valid
if (cardValid == true) {
label.setText("Card brand is valid");
}
waits(1);
text.setText("");
waits(1);
checkDigits();
}
});
cardTypesDD.addActionListener( new ActionListener() {
public void actionPerformed(ActionEvent e) {
//where program really starts
while (cardTypesDD.getSelectedIndex() == 3) {
label.setText("First, please select a card type from DD list");
}
cardType = (String) cardTypesDD.getSelectedItem();
System.out.println(cardType);
if (!cardType.equals("")) {
label.setText("Thank you, now please enter your card #");
}
//now go to the jtextfield actionlistener
}});
}
public static void main(String[] args) {
SwingUtilities.invokeLater(
new Runnable() {
public void run() {
new CreditGraphics();
}});
}
public void verifyScreen() {
//destroy old frame
frame.dispose();
//create new frame essentially same as last frame
vframe = new JFrame("MES Banking App");
vpanel = new JPanel();
titlelabel = new JLabel("Verification Page");
namelabel = new JLabel("Name: ");
namefield = new JTextField(20);
//title section
vpanel.setLayout(new GridBagLayout());
grid = new GridBagConstraints();
grid.fill = GridBagConstraints.PAGE_START;
grid.weightx = 0;
grid.gridx = 0;
grid.gridy = 0;
vpanel.add(titlelabel, grid);
//name section
grid.gridy = 1;
grid.insets = new Insets(10, 0, 0, 0);
vpanel.add(namelabel, grid);
grid.gridx = 1;
grid.insets = new Insets(10, 10, 0, 0);
vpanel.add(namefield, grid);
vframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
vframe.getContentPane().add(vpanel);
vframe.pack();
vframe.setVisible(true);
}
public static void waits(int k) {
long time0, time1;
time0 = System.currentTimeMillis();
do {
time1 = System.currentTimeMillis();
} while ((time1 - time0) < k * 1000);
}
public void validateCard() {
//check brand
cardValid = false;
if ((cardType.equals("Visa") && carddigits.substring(0, 1).equals("4")) && (length == 13 || length == 16)) {
label.setText("Thank you, next step");
cardValid = true;
}
if ((cardType.equals("Master Card")) && (carddigits.substring(0, 2).equals("51") || carddigits.substring(0, 2).equals("52") || carddigits.substring(0, 2).equals("53") || carddigits.substring(0, 2).equals("54") || carddigits.substring(0, 2).equals("55")) && (length == 16)) {
label.setText("Thank you, next step");
cardValid = true;
}
if ((cardType.equals("American Express") && carddigits.substring(0, 2).equals("37") && length == 15)) {
label.setText("Thank you, next step");
cardValid = true;
}
if (cardValid != true) {
System.out.println("ERROR");
label.setText("ERROR");
waits(2);
System.exit(0);
}
//end check
}
public void checkDigits() {
label.setText("Checking digits using Luhn's algorithm...");
waits(2);
//check digits
checkDigits = new int[length];
for (int i = 0; i < length; i++) {
checkDigits[i] = Integer.parseInt(carddigits.substring(i, i + 1));
//successfully puts digits into array
}
for (int e = length - 2; e >= 0; e -= 2) {
checkDigits[e] = 2 * checkDigits[e];
}
for (int d = 0; d < length; d++) {
holdDigitsChar.add(String.valueOf(checkDigits[d]));
}
for (int v = 0; v < length; v++) {
if (holdDigitsChar.get(v).length() == 2) {
holdDigits.add(Integer.parseInt(holdDigitsChar.get(v).substring(0, 1)));
holdDigits.add(Integer.parseInt(holdDigitsChar.get(v).substring(1, 2)));
} else {
holdDigits.add(Integer.parseInt(holdDigitsChar.get(v)));
}
}
for (int c = 0; c < holdDigits.size(); c++) {
checkSum += holdDigits.get(c);
}
System.out.println("Check sum:" + checkSum);
if (checkSum % 10 == 0) {
label.setText("Numbers check out, thank you");
waits(2);
verifyScreen();
} else {
System.out.println("ERROR");
System.exit(0);
}
}
}
导入java.awt.Dimension;
导入java.awt.event.ActionEvent;
导入java.awt.event.ActionListener;
导入javax.swing.JFrame;
导入javax.swing.JLabel;
导入javax.swing.JPanel;
导入javax.swing.JTextField;
导入javax.swing.SwingUtilities;
导入java.util.Scanner;
导入java.util.array;
导入java.io.BufferedWriter;
导入java.io.File;
导入java.io.FileWriter;
导入java.io.IOException;
导入java.util.*;
导入java.util.*;
导入java.io.*;
导入javax.mail.*;
导入javax.mail.event.*;
导入javax.mail.internet.*;
导入javax.activation.*;
导入java.util.Properties;
导入javax.mail.Header;
导入java.util.Enumeration;
导入java.util.Properties;
导入java.applet.*;
导入java.awt.*;
导入java.awt.event.*;
导入java.applet.applet;
导入javax.swing.*;
导入javax.swing.event.*;
导入javax.swing.JApplet;
导入javax.mail.Authenticator;
导入javax.mail.Folder;
导入javax.mail.Header;
导入javax.mail.Message;
导入javax.mail.PasswordAuthentication;
导入javax.mail.Session;
导入javax.mail.URLName;
导入java.beans。*;
导入java.util.ArrayList;
导入javax.swing.SwingUtilities;
导入javax.swing.filechooser.*;
导入java.util.Scanner;
导入java.awt.image.*;
导入java.io.*;
导入java.net.URL;
导入javax.imageio.*;
导入javax.swing.Timer;
公共类信用图形{
//第一屏变量
公共字符串cardNum;
公共框架;
公共JPanel小组;
公共标签;
公共JTextField文本;
公共字符串cardType=“”;
公共字符串卡位;
公共布尔值有效;
公共整数长度;
公共字符串[]卡片类型;
公共JComboBox卡类型SDD;
公共静态ArrayList holdDigits=新ArrayList();
public static ArrayList holdDigitsChar=new ArrayList();
公共静态int[]校验位;
公共静态整数校验和=0;
//验证屏幕中的第二屏幕变量;
公共JFrame vframe;
公共JPanel vpanel;
公共JLabel titlelabel;
公共网格;
公共标签;
公共JTextField namefield;
公共信贷图表(){
frame=新JFrame(“MES银行应用程序”);
panel=新的JPanel();
label=新的JLabel();
cardTypes=新字符串[4];
卡片类型[0]=“Visa”;
卡片类型[1]=“美国运通”;
卡片类型[2]=“主卡”;
卡片类型[3]=“”;
cardTypesDD=新的JComboBox(cardTypes);
卡片类型SDD。设置所选索引(3);
text=新的JTextField(16);
面板。添加(标签);
面板。添加(cardTypesDD);
添加(文本);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
面板。设置首选尺寸(新尺寸(500500));
frame.getContentPane().add(面板);
frame.pack();
frame.setVisible(true);
label.setText(“请输入您的信用卡
‘万事达卡’‘Visa’或‘美国运通’”);
text.addActionListener(新ActionListener(){
已执行的公共无效操作(操作事件e){
//输入CC类型后,提示用户输入数字
carddigits=text.getText();//从jtextfield获取信用卡号码
length=carddigits.length();//设置卡的长度
validateCard();//使用信用卡号和长度来确定它是否与品牌匹配
//如果卡有效,下面返回
如果(cardValid==true){
label.setText(“卡牌有效”);
}
等待(1);
text.setText(“”);
等待(1);
检查数字();
}
});
cardTypesDD.addActionListener(新ActionListener(){
已执行的公共无效操作(操作事件e){
//节目真正从哪里开始
同时(cardTypesDD.getSelectedIndex()==3){
label.setText(“首先,请从DD列表中选择一种卡类型”);
}
cardType=(字符串)cardTypesDD.getSelectedItem();
系统输出打印项次(卡片类型);
如果(!cardType.equals(“”){
label.setText(“谢谢您,现在请输入您的卡#”);
}
//现在转到jtextfield actionlistener
}});
}
公共静态void main(字符串[]args){
SwingUtilities.invokeLater(
新的Runnable(){
公开募捐{
新的CreditGraphics();
}});
}
公共无效验证屏幕(){
//破坏旧框架
frame.dispose();
//创建与上一帧基本相同的新帧
vframe=新JFrame(“MES银行应用程序”);
vpanel=新的JPanel();
标题标签=新的JLabel(“验证页”);
namelabel=新的JLabel(“名称:”);
namefield=新的JTextField(20);
//标题部分
setLayout(新的GridBagLayout());
grid=新的GridBagConstraints();
grid.fill=GridBagConstraints.PAGE\u开始;
grid.weightx=0;
grid.gridx=0;
grid.gridy=0;
vpanel.add(标题标签,网格);
//名称部分
grid.gridy=1;
grid.insets=新的插图(10
List l = new ArrayList();
List<String> l = new ArrayList<>(); //or new ArrayList<String>(); in Java < 7