java一般任务较好的写法举例

1.定义任务

/**
 * 表示一个任务
 *
 */
public interface Task {
	
	/**
	 * 运行实际的任务内容
	 * 
	 * @throws Exception
	 */
	public void runTask() throws Exception;
	
	/**
	 * 返回Task的信息
	 * @return
	 */
	public TaskInfo getTaskInfo();

	/**
	 * 准备参数信息
	 * @param args
	 * @throws Exception
	 */
	void initTaskInfo(String[] args);
	
}

 2.任务信息

/**
 * 表示一个任务的信息
  * 
 */
public class TaskInfo {

	private String taskName;
	// 参数列表
	private Map<String, String> arguments = new HashMap<String, String>();

	public TaskInfo() {
	}

	public TaskInfo(String taskName) {
		this.taskName = taskName;
	}

	public String getTaskName() {
		return taskName;
	}

	public void setTaskName(String taskName) {
		this.taskName = taskName;
	}

	public void addArgument(String argName, String argValue) {
		arguments.put(argName, argValue);
	}

	public String getArgument(String argName) {
		return arguments.get(argName);
	}

	@Override
	public String toString() {
		StringBuilder sb = new StringBuilder();
		sb.append(taskName);

		if (arguments.size() > 0) {
			for (Entry<String, String> arg : arguments.entrySet()) {
				sb.append('[').append(arg.getKey()).append('=').append(arg.getValue()).append(']');
			}
		}

		return sb.toString();
	}

}

 3.任务实现support类。

/**
 * 任务support
 * 
 */
public abstract class TaskSupport implements Task {
	
	protected TaskInfo taskInfo;
	
	@Override
	public void initTaskInfo(String[] args) {
		if (args.length == 0) {
			return;
		}
		taskInfo = new TaskInfo(args[0]);
		
		// 初如化参数列表
		for (int i = 1; i < args.length; i++) {
			String[] argPair = args[i].split("=");
			
			if (initArg(argPair[0], argPair[1])) {
				taskInfo.addArgument(argPair[0], argPair[1]);
			} else {
				Log.warn("Argument ignored: " + args[i]);
			}
		}
	}

	protected boolean initArg(String name, String value) {
		return false;
		
	}

	@Override
	public TaskInfo getTaskInfo() {
		return taskInfo;
	}

	@Override
	final public void runTask() throws Exception {
		initTask();

		try {
			doRunTask();
		} finally {
			afterRunTask();
		}
	}

	/**
	 * 真正处理task的
	 */
	abstract protected void doRunTask() throws Exception;

	/**
	 * 用于收尾工作，如资源的释放等等
	 */
	protected void afterRunTask() throws Exception {

	}

	/**
	 * 初始化task中的一些信息
	 */
	protected void initTask() throws Exception {

	}

}

 

4.任务运行入口

/**
 * 所有task的启动类
 * 
 * 
 */
public class TaskRunner {

	private static final Log log = LogFactory.getLog(TaskRunner.class);

	public static void main(String[] args) {

		Task task = prepareTask(args);

		if (task == null) {
			return;
		}
		
		try {
			log.info("Start running task: " + task.getTaskInfo());
			task.runTask();
			log.info("Finish running task: " + task.getTaskInfo());
		} catch (Exception e) {
			log.error("Error running Task: " + task.getTaskInfo(), e);
		}

	}

	public static Task prepareTask(String[] args) {
		String[] beanFiles = new String[] { "*.xml", "*.xml","*.xml"};

		ApplicationContext context = new ClassPathXmlApplicationContext(beanFiles);

		Map<String, Task> tasks = context.getBeansOfType(Task.class);

		if (args.length < 1 || !tasks.containsKey(args[0])) {
			log.error("No such task: " + args[0]);
			log.info(getTaskListStr(tasks));
			return null;
		}

		Task task = tasks.get(args[0]);
		task.initTaskInfo(args);

		return task;
	}

	private static String getTaskListStr(Map<String, Task> tasks) {
		StringBuilder sb = new StringBuilder("All available tasks: ");
		for (String taskName : tasks.keySet()) {
			sb.append(taskName).append(',');
		}
		return sb.toString();
	}

}