Java 程序在 Netbeans 中运行良好，但是从构建的 JAR 运行时它不起作用

Question

我现在完全是 java 的菜鸟，我想做的就是将 MySQL 日志记录添加到这个 Minecraft 服务器的 Java 代理。

当程序在 NetBeans 中运行时，程序运行良好，没有任何错误。但是，当构建 jar 并从 jar 运行程序时，登录到 Minecraft 服务器时会抛出此错误:

SQLNestedException 错误:无法为连接 URL 'jdbc:mysql://localhost:3306/userips' @ org.apache.commons.dbcp.BasicDataSource:1452 创建类 'com.mysql.jdbc.Driver' 的 JDBC 驱动程序

基本上它应该做的是记录用户的 IP、用户名、时间和登录日期。

我正在使用 Netbeans IDE 7.2.1 并使用 Maven 构建 jar 来处理所有依赖项。

我使用 Maven 将 commons-dbcp-1.4.jar、mysql-connector-java-5.1.22.jar 和 commons-pool-1.5.4.jar 导入到我的依赖项中，它们位于 jar 文件中。

这是建立连接的类:

import java.sql.Connection;
import java.sql.SQLException;
import org.apache.commons.dbcp.BasicDataSource;


public final class ConnectionPooler {

    public static final Configuration config = new Configuration();


    private static final BasicDataSource dataSource = new BasicDataSource();

    static {
        config.load();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl(config.sql_url);
        dataSource.setUsername(config.sql_user);
        dataSource.setPassword(config.sql_pass);
        dataSource.setInitialSize(5);
        dataSource.setMaxActive(30);
    }

    public static Connection getConnection() throws SQLException {
        return dataSource.getConnection();
    } 

}

这里是 mysql 查询和所有执行的类:

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

public class IPLogger {



public boolean logip(String player, String ipp) throws SQLException {
    Connection connection = null;
    PreparedStatement statement = null;
    ResultSet resultSet = null;


    Calendar now = Calendar.getInstance();
    TimeZone timeZone1 = now.getTimeZone();
    String timeZone = timeZone1.getDisplayName();
    DateFormat dateFormat = new SimpleDateFormat("MM/dd/yyyy");
    DateFormat timeFormat = new SimpleDateFormat("HH:mm:ss");
    Date date1 = new Date();
    Date date2 = new Date();
    String date;
    String time;
    date = dateFormat.format(date1);
    time = timeFormat.format(date2);


    String SQL_EXIST = "INSERT INTO `proxyips` (`username`, `ip`,`date`,`time`) VALUES ('"+player+"', '"+ipp+"','"+date+"','"+time+" "+timeZone+"')";

    try{
        connection = ConnectionPooler.getConnection();
        statement = connection.prepareStatement(SQL_EXIST);
        statement.executeUpdate();

    } finally {
        if (resultSet != null) {
            try { resultSet.close(); } catch (SQLException ignore) {ignore.printStackTrace(); }
        }
        if (statement != null) {
            try { statement.close(); } catch (SQLException ignore) {ignore.printStackTrace(); }
        }
        if (connection != null) {
            try { connection.close(); } catch (SQLException ignore) {ignore.printStackTrace(); }
        }
    }       

    return true;
}

}

这是 pom.xml，以防我在构建或类似问题时遇到一些错误:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>net.md-5</groupId>
    <artifactId>BungeeCordKC</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>BungeeCordKC</name>
    <url>http://maven.apache.org</url>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.3.2</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                  <showDeprecation>false</showDeprecation>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>2.0</version>
                <configuration>

                    <filters>
                        <filter>
                            <artifact>*:*</artifact>
                            <excludes>
                                <exclude>**/*.java</exclude>
                                <exclude>**/*.properties</exclude>
                                <exclude>**/*.SF</exclude>
                                <exclude>**/*.DSA</exclude>
                            </excludes>
                        </filter>
                    </filters>

                </configuration>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.4</version>
                <configuration>
                    <archive>
                        <manifestEntries>
                            <Main-Class>${main.class}</Main-Class>
                            <Implementation-Version>${describe}</Implementation-Version>
                        </manifestEntries>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <build.number>unknown</build.number>
        <main.class>net.md_5.bungee.BungeeCord</main.class>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.yaml</groupId>
            <artifactId>snakeyaml</artifactId>
            <version>1.11</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>0.11.4</version>
        </dependency>
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>13.0.1</version>
        </dependency>
        <dependency>
            <groupId>com.google.code.findbugs</groupId>
            <artifactId>annotations</artifactId>
            <version>2.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.bouncycastle</groupId>
            <artifactId>bcprov-ext-jdk15on</artifactId>
            <version>1.47</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.22</version>
            <type>jar</type>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>commons-dbcp</groupId>
            <artifactId>commons-dbcp</artifactId>
            <version>1.4</version>
        </dependency>
        <dependency>
            <artifactId>commons-pool</artifactId>
            <groupId>commons-pool</groupId>
            <type>jar</type>
            <version>1.5.4</version>
        </dependency>
    </dependencies>
</project>

如果有人知道哪里出了问题，或者如果您对我如何设置环境有任何疑问，请告诉我。

编辑:这是我将该 catch 语句添加到 try block 时的完整堆栈跟踪。

org.apache.commons.dbcp.SQLNestedException: Cannot create JDBC driver of class '
com.mysql.jdbc.Driver' for connect URL 'jdbc:mysql://localhost.com:3306/use
rips'
        at org.apache.commons.dbcp.BasicDataSource.createConnectionFactory(Basic
DataSource.java:1452)
        at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSou
rce.java:1371)
        at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource
.java:1044)
        at net.md_5.bungee.ConnectionPooler.getConnection(ConnectionPooler.java:
30)
        at net.md_5.bungee.IPLogger.logip(IPLogger.java:44)
        at net.md_5.bungee.InitialHandler.run(InitialHandler.java:77)
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
        at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
        at java.util.concurrent.FutureTask.run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ExceptionInInitializerError
        at com.mysql.jdbc.Util.stackTraceToString(Util.java:355)
        at com.mysql.jdbc.Util.<clinit>(Util.java:120)
        at com.mysql.jdbc.NonRegisteringDriver.parseURL(NonRegisteringDriver.jav
a:764)
        at com.mysql.jdbc.NonRegisteringDriver.acceptsURL(NonRegisteringDriver.j
ava:265)
        at java.sql.DriverManager.getDriver(Unknown Source)
        at org.apache.commons.dbcp.BasicDataSource.createConnectionFactory(Basic
DataSource.java:1437)
        ... 11 more
Caused by: java.lang.RuntimeException: Can't load resource bundle due to underly
ing exception java.util.MissingResourceException: Can't find bundle for base nam
e com.mysql.jdbc.LocalizedErrorMessages, locale en_US
        at com.mysql.jdbc.Messages.<clinit>(Messages.java:61)
        ... 17 more
Caused by: java.util.MissingResourceException: Can't find bundle for base name c
om.mysql.jdbc.LocalizedErrorMessages, locale en_US
        at java.util.ResourceBundle.throwMissingResourceException(Unknown Source
)
        at java.util.ResourceBundle.getBundleImpl(Unknown Source)
        at java.util.ResourceBundle.getBundle(Unknown Source)
        at com.mysql.jdbc.Messages.<clinit>(Messages.java:59)
        ... 17 more

Answer 1

错误的原因是您排除了 .properties使用 maven-shade 构建 JAR 时的文件。我强烈建议您不要构建大 jar，而只需按预期使用类路径机制并将驱动程序等保存在它们自己的 jar 文件中。

堆栈跟踪的以下部分证明了这一点:

Caused by: java.lang.RuntimeException: Can't load resource bundle due to underly
ing exception java.util.MissingResourceException: Can't find bundle for base nam
e com.mysql.jdbc.LocalizedErrorMessages, locale en_US
        at com.mysql.jdbc.Messages.<clinit>(Messages.java:61)

资源包也是.properties .

因此，要解决此问题，我的第一个建议是不要构建一个大 jar ，否则，您将需要通过删除 <exclude>**/*.properties</exclude> 来更改 maven-shade exlusion 过滤器。来自:

<filters>
    <filter>
        <artifact>*:*</artifact>
        <excludes>
            <exclude>**/*.java</exclude>
            <exclude>**/*.properties</exclude>
            <exclude>**/*.SF</exclude>
            <exclude>**/*.DSA</exclude>
        </excludes>
    </filter>
</filters>

它在您的 IDE 中工作的原因是它使用使用 maven 下载的实际 JAR 文件。