ZooKeeper小练习

问题重现：

1、级联查看某节点下所有节点及节点值
2、删除一个节点，不管有有没有任何子节点
3、级联创建任意节点
4、清空子节点

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;

/**
 * 编程思维训练
 * 1、级联查看某节点下所有节点及节点值
 * 2、删除一个节点，不管有有没有任何子节点
 * 3、级联创建任意节点
 * 4、清空子节点
 */
public class ZKHomeWork {

	private static String HOST_PATH = "hadoop02:2181,hadoop03:2181,hadoop04:2181";
	private static int TIME_OUT = 5000;
	static ZooKeeper zk = null;
	static Map<String,String> map = new HashMap<>();
	
	
	public static void main(String[] args) throws Exception {
		zk = new ZooKeeper(HOST_PATH, TIME_OUT, null);
		
		/*for (Map.Entry<String, String> entry : getChildNodeAndValue("/zk").entrySet()) {  
		    System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());  
		}*/
		
		/*if(rmr("/test/aaa/bbb",zk)){
			System.out.println("删除成功");
		}*/
		
		
		/*if(createZNode("/test/aaa/bbb/ccc/ddd/eee","eee",zk)){
			System.out.println("创建成功");
		}*/
		
		/*if(clearChildNode("/test/aaa",zk)){
			System.out.println("删除成功");
		}*/
	}

	/**
	 * 级联查看某节点下所有节点及节点值
	 * @param path
	 * @return
	 * @throws Exception
	 */
	public static Map<String, String> getChildNodeAndValue(String path) throws Exception{
	
		List<String> sonNode = sonNode(path);
		if(sonNode.size() > 0){
			for (String child : sonNode) {
				byte[] data = zk.getData(path+"/"+child, false, null);
				map.put(path, new String(data));
				getChildNodeAndValue(path+"/"+child);
			}
		}else{
			byte[] data = zk.getData(path, false, null);
			map.put(path, new String(data));
		}
		return map;
	}
	
	/**
	 * 查看某个节点下是不是有子节点
	 * @param path
	 * @return
	 * @throws Exception 
	 */
	public static List<String> sonNode(String path) throws Exception{
		List<String> children = zk.getChildren(path, null);
		return children;
	}

	/**
	 * 删除一个节点，不管有有没有任何子节点
	 * @param path
	 * @param zk
	 * @return
	 * @throws Exception
	 */
	public static boolean rmr(String path, ZooKeeper zk) throws Exception {
		List<String> sonNode = sonNode(path);
		boolean flag = false;
		String parentPath = "";
		if(sonNode.size() > 0){
			for (String child : sonNode) {
				parentPath = path;
				rmr(path+"/"+child,zk);
			}
			if(sonNode(parentPath).size() == 0){
				zk.delete(path, -1);
			}
		}else{
			zk.delete(path, -1);
			flag = true;
		}
		
		return flag;
	}

	/**
	 * 级联创建任意节点
	 * @param znodePath
	 * @param data
	 * @param zk
	 * @return
	 * @throws Exception
	 */
	public static boolean createZNode(String znodePath, String data, ZooKeeper zk) throws Exception {
		String[] paths = znodePath.split("/");
		String path = "";
		for (int i = 1; i < paths.length; i++) {
			path = path +"/"+ paths[i];
			Stat exists = zk.exists(path, null);
			if(exists == null){
				if(i == paths.length-1){
					zk.create(path, data.getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
				}else{
					zk.create(path, "".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
				}
			}
		}
		return true;
	}

	/**
	 * 清空子节点
	 * @param znodePath
	 * @param zk
	 * @return
	 * @throws Exception
	 */
	public static boolean clearChildNode(String znodePath, ZooKeeper zk) throws Exception {
		String grandPath = znodePath;
		List<String> sonNode = sonNode(znodePath);
		boolean flag = false;
		String parentPath = "";
		if(sonNode.size() > 0){
			for (String child : sonNode) {
				parentPath = znodePath;
				rmr(znodePath+"/"+child,zk);
			}
			if(!grandPath.equals(parentPath) && sonNode(parentPath).size() == 0){
				zk.delete(znodePath, -1);
			}
		}else{
			zk.delete(znodePath, -1);
			flag = true;
		}
		
		return flag;
	}
	
}