假设我们有三个任务，分别是Task1、Task2和Task3。Task1和Task2是独立的任务，Task3依赖于Task1和Task2的输出结果。
Task1的代码：
代码语言：javascript复制@Component
public class Task1 implements CommandLineRunner {
@Override
public void run(String... args) throws Exception {
System.out.println("Task1 is running");
}
}Task2的代码：
代码语言：javascript复制@Component
public class Task2 implements CommandLineRunner {
@Override
public void run(String... args) throws Exception {
System.out.println("Task2 is running");
}
}Task3的代码：
代码语言：javascript复制@Component
public class Task3 implements CommandLineRunner {
@Override
public void run(String... args) throws Exception {
System.out.println("Task3 is running with input1=" args[0] " and input2=" args[1]);
}
}TaskDependencyListener的代码：：
代码语言：javascript复制@Component
public class TaskDependencyListener implements TaskExecutionListener {
private final TaskExecutionRepository taskExecutionRepository;
public TaskDependencyListener(TaskExecutionRepository taskExecutionRepository) {
this.taskExecutionRepository = taskExecutionRepository;
}
@Override
public void onTaskEnd(TaskExecution taskExecution) {
String taskName = taskExecution.getTaskName();
if ("Task1".equals(taskName) || "Task2".equals(taskName)) {
TaskExecution lastExecution = taskExecutionRepository.getLastTaskExecutionForTaskName(taskName);
if (lastExecution != null && lastExecution.getExitCode() == 0) {
TaskExecution task3 = new TaskExecution();
task3.setTaskName("Task3");
task3.setArguments(Arrays.asList("--input1=" lastExecution.getExitMessage(), "--input2=" taskExecution.getExitMessage()));
taskExecutionRepository.createTaskExecution(task3);
}
}
}
@Override
public void onTaskFailed(TaskExecution taskExecution, Throwable throwable) {
}
@Override
public void onTaskStartup(TaskExecution taskExecution) {
}
@Override
public void onTaskEndFailed(TaskExecution taskExecution, Throwable throwable) {
}
}在这个例子中，TaskDependencyListener实现了TaskExecutionListener接口，并在onTaskEnd方法中监听任务的执行结果。当Task1或Task2执行结束时，会查询它们的最后一次执行结果，如果执行成功，则创建一个新的Task3，并将Task1和Task2的输出结果作为输入参数传递给Task3。这样就实现了Task3依赖于Task1和Task2的动态依赖关系。
为了让TaskDependencyListener生效，需要在Spring Boot应用程序的配置文件中添加如下配置：
代码语言：javascript复制spring.cloud.task.execution.listeners=com.example.TaskDependencyListener这个配置指定了要使用TaskDependencyListener来监听任务的执行结果。
