snaker-core/src/main/java/org/snaker/engine/entity/HistoryTask.java
public Task undoTask() {
    	Task task = new Task();
    	task.setOrderId(this.getOrderId());;
    	task.setTaskName(this.getTaskName());
    	task.setDisplayName(this.getDisplayName());
    	task.setTaskType(this.getTaskType());
    	task.setExpireTime(this.getExpireTime());
    	task.setActionUrl(this.getActionUrl());
    	task.setParentTaskId(this.getParentTaskId());
    	task.setVariable(this.getVariable());
    	task.setPerformType(this.getPerformType());
    	task.setOperator(this.getOperator());
    	return task;
    }
public Task undoTask() {
    	Task task = new Task();
    	task.setOrderId(this.getOrderId());;
    	task.setTaskName(this.getTaskName());
    	task.setDisplayName(this.getDisplayName());
    	task.setTaskType(this.getTaskType());
    	task.setExpireTime(this.getExpireTime());
    	task.setActionUrl(this.getActionUrl());
    	task.setParentTaskId(this.getParentTaskId());
    	task.setVariable(this.getVariable());
    	task.setPerformType(this.getPerformType());
    	task.setOperator(this.getOperator());
    	return task;
    }
根据历史任务产生撤回的任务对象
@return 任务对象