进程 'command'/Users/alvinpeng/.sdkman/candidates/java/11.0.8.hs-adpt/bin/java'' 以非零退出值 255 结束

Question

当我尝试在 Intellij 中使用 java 连接本地服务器时，出现此错误。我不知道它是什么错误，它来自哪个部分。任何人都可以启发我吗？我已经在 libs 中获得了 postgresql jdbc 驱动程序。

当我用 intellij 运行它时，它说：

/Users/alvinpeng/.sdkman/candidates/java/11.0.8.hs-adpt/bin/java -javaagent:/Users/alvinpeng/Library/Application Support/JetBrains/Toolbox/apps/IDEA-C/ch-0/202.7319.50/IntelliJ IDEA CE.app/Contents/lib/idea_rt.jar=51001:/Users/alvinpeng/Library/Application Support/JetBrains/Toolbox/apps/IDEA-C/ch-0/202.7319.50/IntelliJ IDEA CE.app/Contents/bin -Dfile.encoding=UTF-8 -classpath /Users/alvinpeng/Desktop/program/out/production/classes:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.guava/guava/28.2-jre/8ec9ed76528425762174f0011ce8f74ad845b756/guava-28.2-jre.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.guava/failureaccess/1.0.1/1dcf1de382a0bf95a3d8b0849546c88bac1292c9/failureaccess-1.0.1.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.guava/listenablefuture/9999.0-empty-to-avoid-conflict-with-guava/b421526c5f297295adef1c886e5246c39d4ac629/listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.code.findbugs/jsr305/3.0.2/25ea2e8b0c338a877313bd4672d3fe056ea78f0d/jsr305-3.0.2.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/org.checkerframework/checker-qual/2.10.0/5786699a0cb71f9dc32e6cca1d665eef07a0882f/checker-qual-2.10.0.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.errorprone/error_prone_annotations/2.3.4/dac170e4594de319655ffb62f41cbd6dbb5e601e/error_prone_annotations-2.3.4.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.j2objc/j2objc-annotations/1.3/ba035118bc8bac37d7eff77700720999acd9986d/j2objc-annotations-1.3.jar program.App
Unable to load the class. Terminating the program

Process finished with exit code 255

当我尝试用 gradle 运行它时，它说：

The client will now receive all logging from the daemon (pid: 2592). The daemon log file: /Users/alvinpeng/.gradle/daemon/6.4/daemon-2592.out.log
Starting 7th build in daemon [uptime: 1 hrs 55 mins 42.971 secs, performance: 96%, non-heap usage: 22% of 268.4 MB]
Using 8 worker leases.
Starting Build
Settings evaluated using settings file '/Users/alvinpeng/Desktop/program/settings.gradle'.
Projects loaded. Root project using build file '/Users/alvinpeng/Desktop/program/build.gradle'.
Included projects: [root project 'program']

> Configure project :
Evaluating root project 'program' using build file '/Users/alvinpeng/Desktop/program/build.gradle'.
All projects evaluated.
Selected primary task 'App.main()' from project :
Tasks to be executed: [task ':compileJava', task ':processResources', task ':classes', task ':App.main()']
Tasks that were excluded: []
:compileJava (Thread[Execution worker for ':',5,main]) started.

> Task :compileJava UP-TO-DATE
Caching disabled for task ':compileJava' because:
  Build cache is disabled
Skipping task ':compileJava' as it is up-to-date.
:compileJava (Thread[Execution worker for ':',5,main]) completed. Took 0.018 secs.
:processResources (Thread[Execution worker for ':',5,main]) started.

> Task :processResources NO-SOURCE
Skipping task ':processResources' as it has no source files and no previous output files.
:processResources (Thread[Execution worker for ':',5,main]) completed. Took 0.0 secs.
:classes (Thread[Execution worker for ':',5,main]) started.

> Task :classes UP-TO-DATE
Skipping task ':classes' as it has no actions.
:classes (Thread[Execution worker for ':',5,main]) completed. Took 0.0 secs.
:App.main() (Thread[Execution worker for ':',5,main]) started.

> Task :App.main() FAILED
Caching disabled for task ':App.main()' because:
  Build cache is disabled
Task ':App.main()' is not up-to-date because:
  Task has not declared any outputs despite executing actions.
Starting process 'command '/Users/alvinpeng/.sdkman/candidates/java/11.0.8.hs-adpt/bin/java''. Working directory: /Users/alvinpeng/Desktop/program Command: /Users/alvinpeng/.sdkman/candidates/java/11.0.8.hs-adpt/bin/java -Dfile.encoding=UTF-8 -Duser.country=AU -Duser.language=en -Duser.variant -cp /Users/alvinpeng/Desktop/program/build/classes/java/main:/Users/alvinpeng/Desktop/program/build/resources/main:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.guava/guava/28.2-jre/8ec9ed76528425762174f0011ce8f74ad845b756/guava-28.2-jre.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.guava/failureaccess/1.0.1/1dcf1de382a0bf95a3d8b0849546c88bac1292c9/failureaccess-1.0.1.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.guava/listenablefuture/9999.0-empty-to-avoid-conflict-with-guava/b421526c5f297295adef1c886e5246c39d4ac629/listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.code.findbugs/jsr305/3.0.2/25ea2e8b0c338a877313bd4672d3fe056ea78f0d/jsr305-3.0.2.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/org.checkerframework/checker-qual/2.10.0/5786699a0cb71f9dc32e6cca1d665eef07a0882f/checker-qual-2.10.0.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.errorprone/error_prone_annotations/2.3.4/dac170e4594de319655ffb62f41cbd6dbb5e601e/error_prone_annotations-2.3.4.jar:/Users/alvinpeng/.gradle/caches/modules-2/files-2.1/com.google.j2objc/j2objc-annotations/1.3/ba035118bc8bac37d7eff77700720999acd9986d/j2objc-annotations-1.3.jar program.App
Successfully started process 'command '/Users/alvinpeng/.sdkman/candidates/java/11.0.8.hs-adpt/bin/java''
Unable to load the class. Terminating the program
:App.main() (Thread[Execution worker for ':',5,main]) completed. Took 0.123 secs.
2 actionable tasks: 1 executed, 1 up-to-date

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':App.main()'.
> Process 'command '/Users/alvinpeng/.sdkman/candidates/java/11.0.8.hs-adpt/bin/java'' finished with non-zero exit value 255

get_connection函数：

主要功能：

Answer 1

JDBC 驱动程序 jar 不在类路径中。

我已经在 libs 中获得了 postgresql jdbc 驱动程序

如果您在本地直接用于基于 Gradle 的项目，您还需要调整 build.gradle 文件以将本地 jar 包含到类路径 like described here 中：

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
}

但是，只包含存储库依赖项应该更容易，以便 Gradle 可以自动下载和配置驱动程序。

dependencies {
    compile group: 'org.postgresql', name: 'postgresql', version: '9.4-1206-jdbc42'
}

不确定此项目需要什么 JDBC 驱动程序版本。您可以check this link 获取所有可用版本并调整build.gradle 中的依赖关系。

不要忘记reimport the project，以便 IDE 了解新的依赖项。

对于不使用 Gradle/Maven 的项目，需要手动将 JDBC jar 添加到 module dependencies。