我在netbeans中创建了一个项目，使用SQLite作为数据库。当我在netbeans中运行它时，它运行得很好，当我使用“java -jar .jar”运行jar时，它会抛出此异常
H:>java -jar Remote_PC_Manger.jar Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at com.halorpm.main.LocalDB.checkAnonymous(LocalDB.java:74) at com.halorpm.main.MainForm.initComponents(MainForm.java:172) at com.halorpm.main.MainForm.(MainForm.java:137) at com.halorpm.main.Core.(Core.java:32) at com.halorpm.main.Core$3.run(Core.java:142) at java.awt.event.InvocationEvent.dispatch(Unknown Source) at java.awt.EventQueue.dispatchEventImpl(Unknown Source) at java.awt.EventQueue.access$200(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.awt.EventQueue$3.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Sour ce) at java.awt.EventQueue.dispatchEvent(Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.pumpEvents(Unknown Source) at java.awt.EventDispatchThread.run(Unknown Source)
MainForm.java
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package com.halorpm.main;
import java.awt.SystemTray;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.sql.SQLException;
/**
*
* @author Abhijith S
*/
public class MainForm extends javax.swing.JFrame {
public String fullname;
public String key;
public int status;
public MainForm() {
Thread getinfo = new Thread() {
@Override
public void run() {
try {
// Send the request
URL url = new URL("http://demiracles.com/halo/cgi/getmisc.php?uname="+Login.username+"&key=name");
URL url1 = new URL("http://demiracles.com/halo/cgi/getmisc.php?uname="+Login.username+"&key=skey");
URLConnection conn = url.openConnection();
URLConnection conn1 = url1.openConnection();
conn.setDoOutput(true);
// OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());
//write parameters
// writer.write(data);
// writer.flush();
// Get the response
StringBuilder answer = new StringBuilder();
StringBuilder answer1 = new StringBuilder();
BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
BufferedReader reader1 = new BufferedReader(new InputStreamReader(conn1.getInputStream()));
String line;
while ((line = reader.readLine()) != null) {
//System.out.println(line);
answer.append(line);
}
while ((line = reader1.readLine()) != null) {
//System.out.println(line);
answer1.append(line);
}
// writer.close();
reader.close();
reader1.close();
//Output the response
//System.out.println(answer.toString());
fullname = answer.toString();
key = answer1.toString();
regname.setText(fullname);
lic.setText(key);
expire.setText("2018-November-20");
} catch (MalformedURLException ex) {
ex.printStackTrace();
} catch (IOException ex) {
ex.printStackTrace();
}
}
};
getinfo.start();
/* Thread mainer = new Thread(){
public void run(){
System.out.println("out");
while(true){
try{
System.out.println("sasasa");
URL url = new URL("http://demiracles.com/halo/cgi/java_checker.php?uname="+Login.username+
"&pwd="+Login.password);
URLConnection urlcon = url.openConnection();
BufferedReader bf = new BufferedReader(new InputStreamReader(urlcon.getInputStream()));
String xresponse = bf.readLine();
System.out.println("In ThreadCheck"+xresponse);
new Functions(xresponse);
break;
}catch(Exception x){
System.out.println(x);
}
}
}
};
mainer.start();
*/
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
buttonGroup1 = new javax.swing.ButtonGroup();
buttonGroup2 = new javax.swing.ButtonGroup();
buttonGroup3 = new javax.swing.ButtonGroup();
regname = new javax.swing.JLabel();
jCheckBox1 = new javax.swing.JCheckBox();
lic = new javax.swing.JLabel();
expire = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
jLabel1 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setMinimumSize(new java.awt.Dimension(640, 480));
setResizable(false);
getContentPane().setLayout(null);
getContentPane().add(regname);
regname.setBounds(400, 40, 210, 20);
jCheckBox1.setText("Anonymous");
LocalDB ob = new LocalDB();
int res = ob.checkAnonymous();
if(res==1) {
jCheckBox1.setSelected(true);
}
jCheckBox1.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jCheckBox1ItemStateChanged(evt);
}
});
jCheckBox1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jCheckBox1ActionPerformed(evt);
}
});
getContentPane().add(jCheckBox1);
jCheckBox1.setBounds(40, 190, 81, 23);
getContentPane().add(lic);
lic.setBounds(400, 70, 210, 20);
getContentPane().add(expire);
expire.setBounds(400, 100, 210, 20);
jLabel2.setFont(new java.awt.Font("Tahoma", 0, 12)); // NOI18N
jLabel2.setText("Registered to : ");
getContentPane().add(jLabel2);
jLabel2.setBounds(310, 40, 90, 15);
jLabel3.setFont(new java.awt.Font("Tahoma", 0, 12)); // NOI18N
jLabel3.setText("License : ");
getContentPane().add(jLabel3);
jLabel3.setBounds(310, 70, 90, 15);
jLabel4.setFont(new java.awt.Font("Tahoma", 0, 12)); // NOI18N
jLabel4.setText("Expire on :");
getContentPane().add(jLabel4);
jLabel4.setBounds(310, 100, 90, 15);
jLabel1.setIcon(new javax.swing.ImageIcon(getClass().getResource("/com/halorpm/main/bg_main.png"))); // NOI18N
getContentPane().add(jLabel1);
jLabel1.setBounds(0, 0, 640, 480);
pack();
}// </editor-fold>
private void jCheckBox1ActionPerformed(java.awt.event.ActionEvent evt) {
}
private void jCheckBox1ItemStateChanged(java.awt.event.ItemEvent evt) {
FileManager ob = new FileManager();
LocalDB db = new LocalDB();
if(jCheckBox1.isSelected()== true) {
db.addUpdate(1);
ob.createFile();
this.setVisible(false);
if(Core.appStatus==0) {
Core.runTray();
}
}else {
db.addUpdate(0);
ob.deleteFile();
}
}
public void viewDisplay() {
setVisible(true);
}
/**
* @param args the command line arguments
*/
// Variables declaration - do not modify
private javax.swing.ButtonGroup buttonGroup1;
private javax.swing.ButtonGroup buttonGroup2;
private javax.swing.ButtonGroup buttonGroup3;
private javax.swing.JLabel expire;
protected javax.swing.JCheckBox jCheckBox1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JLabel lic;
private javax.swing.JLabel regname;
// End of variables declaration
}
enter code here
enter code here
LocalDB.java
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package com.halorpm.main;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/**
*
* @author Abhijith S
*/
public class LocalDB {
private Connection con;
protected Statement st;
// protected ResultSet res;
int status;
String uname;
String pass;
public LocalDB() {
try {
// sqlite driver
Class.forName("org.sqlite.JDBC");
// database path, if it's new database,
// it will be created in the project folder
con = DriverManager.getConnection("jdbc:sqlite:halodb.db");
try{
st = con.createStatement();
// String qry3 = "UPDATE userlog SET anonymous=1";
//
//System.out.println("done");
}catch(SQLException e) {
}
}catch(ClassNotFoundException | SQLException e) {
}
}
public int checkAnonymous(){
try {
String qry1 = "SELECT * FROM userlog";
// st.executeUpdate(qry3);
ResultSet res = st.executeQuery(qry1);
while(res.next()) {
status = res.getInt("anonymous");
System.out.println("Anonymous = "+status);
}
}catch(SQLException e){
}
return status;
}
public void addUpdate(int a) {
try {
// String table = "CREATE TABLE userlog (uname VARCHAR, pass VARCHAR, anonymous INTEGER, normal INTEGER)";
//String qry = "INSERT INTO userlog values('abi','12345',0,1)";
String qry3 = "UPDATE userlog SET anonymous="+a;
st.executeUpdate(qry3);
}catch(SQLException e) {
e.printStackTrace();
}
}
}
最佳答案
当您使用-jar命令行选项时，它会忽略CLASSPATH。我怀疑您的 Netbeans 项目具有所有依赖项，而当您进入命令行时，这些依赖项会丢失。尝试再次运行:
java -cp %CLASSPATH%;Remote_PC_Manger.jar <main-class>
在 CLASSPATH 中设置所有库依赖项(例如 SQLite)(或者也将它们直接添加到命令行)。
编辑:
仔细观察后，我认为您的异常(LocalDB 中的第 74 行)似乎是这一行:
ResultSet res = st.executeQuery(qry1);
这意味着 st 为 null -- 这意味着 st = con.createStatement(); 进一步失败。您正在捕获这些异常，但不对它们执行任何操作(正如 Hovercraft 所指出的)。至少记录它们。我想您会发现您遇到的异常是由于之前的问题造成的。
我怀疑当您从 jar 运行时，Class.forName("org.sqlite.JDBC"); 行会抛出 ClassNotFoundException。
关于java - 使用 jar 时抛出异常，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/15962059/