从Flink client提交源码看第三方jar包的动态加载的解决方案是怎样的

exec $JAVA_RUN $JVM_ARGS $FLINK_ENV_JAVA_OPTS "${log_setting[@]}" -classpath "`manglePathList "$CC_CLASSPATH:$INTERNAL_HADOOP_CLASSPATHS"`" org.apache.flink.client.cli.CliFrontend "$@

switch (action) {
	case ACTION_RUN:
		run(params);
		return 0;
	case ACTION_RUN_APPLICATION:
		runApplication(params);
		return 0;
	case ACTION_LIST:
		list(params);
		return 0;
	case ACTION_INFO:
		info(params);
		return 0;
	case ACTION_CANCEL:
		cancel(params);
		return 0;
	case ACTION_STOP:
		stop(params);
		return 0;
	case ACTION_SAVEPOINT:
		savepoint(params);
		return 0;
}

protected void run(String[] args) throws Exception {
		LOG.info("Running 'run' command.");

		final Options commandOptions = CliFrontendParser.getRunCommandOptions();
		final CommandLine commandLine = getCommandLine(commandOptions, args, true);

		// evaluate help flag
		if (commandLine.hasOption(HELP_OPTION.getOpt())) {
			CliFrontendParser.printHelpForRun(customCommandLines);
			return;
		}

		final CustomCommandLine activeCommandLine =
				validateAndGetActiveCommandLine(checkNotNull(commandLine));

		final ProgramOptions programOptions = ProgramOptions.create(commandLine);
        # 创建 PackagedProgram 对象
		final PackagedProgram program =
				getPackagedProgram(programOptions);
        #解析获取相关依赖jar
		final List<URL> jobJars = program.getJobJarAndDependencies();
		# 生成最终提交配置
        final Configuration effectiveConfiguration = getEffectiveConfiguration(
				activeCommandLine, commandLine, programOptions, jobJars);

		LOG.debug("Effective executor configuration: {}", effectiveConfiguration);

		try {
			executeProgram(effectiveConfiguration, program);
		} finally {
			program.deleteExtractedLibraries();
		}
	}

return PackagedProgram.newBuilder()
			.setJarFile(jarFile)
			.setUserClassPaths(classpaths)
			.setEntryPointClassName(entryPointClass)
			.setConfiguration(configuration)
			.setSavepointRestoreSettings(runOptions.getSavepointRestoreSettings())
			.setArguments(programArgs)
			.build();

private PackagedProgram(
			@Nullable File jarFile,
			List<URL> classpaths,
			@Nullable String entryPointClassName,
			Configuration configuration,
			SavepointRestoreSettings savepointRestoreSettings,
			String... args) throws ProgramInvocationException {
		this.classpaths = checkNotNull(classpaths);
		this.savepointSettings = checkNotNull(savepointRestoreSettings);
		this.args = checkNotNull(args);

		checkArgument(jarFile != null || entryPointClassName != null, "Either the jarFile or the entryPointClassName needs to be non-null.");

		// whether the job is a Python job.
		this.isPython = isPython(entryPointClassName);

		// load the jar file if exists
		this.jarFile = loadJarFile(jarFile);

		assert this.jarFile != null || entryPointClassName != null;

		// now that we have an entry point, we can extract the nested jar files (if any)
		this.extractedTempLibraries = this.jarFile == null ? Collections.emptyList() : extractContainedLibraries(this.jarFile);
		this.userCodeClassLoader = ClientUtils.buildUserCodeClassLoader(
			getJobJarAndDependencies(),
			classpaths,
			getClass().getClassLoader(),
			configuration);

		// load the entry point class
		this.mainClass = loadMainClass(
			// if no entryPointClassName name was given, we try and look one up through the manifest
			entryPointClassName != null ? entryPointClassName : getEntryPointClassNameFromJar(this.jarFile),
			userCodeClassLoader);

		if (!hasMainMethod(mainClass)) {
			throw new ProgramInvocationException("The given program class does not have a main(String[]) method.");
		}
	}

final Configuration effectiveConfiguration = getEffectiveConfiguration(
				activeCommandLine, commandLine, programOptions, jobJars);

executeProgram(effectiveConfiguration, program);

public static void executeProgram(
			PipelineExecutorServiceLoader executorServiceLoader,
			Configuration configuration,
			PackagedProgram program,
			boolean enforceSingleJobExecution,
			boolean suppressSysout) throws ProgramInvocationException {
		checkNotNull(executorServiceLoader);
		final ClassLoader userCodeClassLoader = program.getUserCodeClassLoader();
		final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
		try {
# 设置用户上下文用户类加载器
Thread.currentThread().setContextClassLoader(userCodeClassLoader);

			LOG.info("Starting program (detached: {})", !configuration.getBoolean(DeploymentOptions.ATTACHED));

			ContextEnvironment.setAsContext(
				executorServiceLoader,
				configuration,
				userCodeClassLoader,
				enforceSingleJobExecution,
				suppressSysout);

			StreamContextEnvironment.setAsContext(
				executorServiceLoader,
				configuration,
				userCodeClassLoader,
				enforceSingleJobExecution,
				suppressSysout);

			try {
                # 反射调用户的 main 函数执行job提交
				program.invokeInteractiveModeForExecution();
			} finally {
				ContextEnvironment.unsetAsContext();
				StreamContextEnvironment.unsetAsContext();
			}
		} finally {
			Thread.currentThread().setContextClassLoader(contextClassLoader);
		}
	}