JDBC 連接到 mySQL RDS 實例

Question

我正在嘗試從 java 連接到我的 RDS mysql 實例

public class App
 {

  public static void main(String[] args)
  {
   try {
    Class.forName("com.mysql.jdbc.Driver");
    } catch (ClassNotFoundException e) {
    System.out.println("Where is your MySQL JDBC Driver?");
    e.printStackTrace();
    return;
    }

我正在使用 maven 來構建。這里是我的 pom.xml

<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>com.mycompany.app</groupId>
<artifactId>my-app</artifactId>
<version>1.0-SNAPSHOT</version>

<properties>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>

<dependencies>
<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.12</version>
  <scope>test</scope>
</dependency>

<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>5.1.6</version>
  </dependency>
</dependencies>

<build>
<plugins>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-jar-plugin</artifactId>
        <version>2.4</version>
        <configuration>
            <archive>
                <index>true</index>
                <manifest>
                    <mainClass>com.mycompany.app.App</mainClass>
                </manifest>
            </archive>
        </configuration>
     </plugin>
     </plugins>
   </build>

</project>

我的構建成功了。但是當我嘗試運行 .jar 文件時

java -jar my-app-1.0-SNAPSHOT.jar
   Where is your MySQL JDBC Driver?
   java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
    at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:351)

我已經提供了正確的驅動程序，但為什么仍然出現錯誤？ 我給出的依賴是不正確的？

Answer 1

根據我的理解，您創建的 jar 文件不包含其他依賴項，請在您的 pom.xml 文件中添加以下代碼。

<plugins>
    <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.3.2</version>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
            </configuration>
        </plugin>
   <plugin>
    <artifactId>maven-assembly-plugin</artifactId>
    <executions>
      <execution>
        <phase>package</phase>
        <goals>
          <goal>single</goal>
        </goals>
      </execution>
    </executions>
    <configuration>
      <archive>
        <manifest>
          <addClasspath>true</addClasspath>
          <mainClass>fully.qualified.MainClass</mainClass>
        </manifest>
      </archive>
      <descriptorRefs>
        <descriptorRef>jar-with-dependencies</descriptorRef>
      </descriptorRefs>
    </configuration>
  </plugin> 
  </plugins>

希望它對你有用