ZooKeeper学习之路 （六）ZooKeeper API的简单使用（二）级联删除与创建详解大数据

 1 public class ZKTest { 
 2  
 3     private static final String CONNECT_STRING = "hadoop1,hadoop2,hadoop3"; 
 4     private static final int SESSION_TIMEOUT = 5000; 
 5     private static ZooKeeper zk = null; 
 6  
 7     public static void main(String[] args) throws Exception { 
 8         zk = new ZooKeeper(CONNECT_STRING, SESSION_TIMEOUT, null); 
 9          
10         //1、级联查看某节点下所有节点及节点值  
11         /*Map<String, String> map = new HashMap<>(); 
12         Map<String, String> maps = ZKUtil.getChildNodeAndValue("/a",zk,map); 
13         maps.forEach((key, value) -> System.out.println(key + "/t" + value));*/ 
14          
15         //2、删除一个节点，不管有有没有任何子节点  
16         /*boolean flag = ZKUtil.rmr("/x", zk); 
17         if(flag) { 
18             System.out.println("删除成功！"); 
19         }else { 
20             System.out.println("删除失败"); 
21         }*/ 
22          
23          
24         //3、级联创建任意节点  
25         /*boolean createZNode = ZKUtil.createZNode("/x/y/z/bb", "bb", zk); 
26         if(createZNode) { 
27             System.out.println("创建成功！"); 
28         }else { 
29             System.out.println("创建失败"); 
30         }*/ 
31          
32          
33         //4、清空子节点 
34         boolean clearChildNode = ZKUtil.clearChildNode("/x", zk); 
35         if(clearChildNode) { 
36             System.out.println("删除成功！"); 
37         }else { 
38             System.out.println("删除失败"); 
39         } 
40          
41      
42         zk.close(); 
43     } 
44  
45      
46 }

  1 public class ZKUtil { 
  2      
  3     private ZooKeeper zk; 
  4      
  5     public ZKUtil() {} 
  6  
  7     public ZooKeeper getZk() { 
  8         return zk; 
  9     } 
 10  
 11     public void setZk(ZooKeeper zk) { 
 12         this.zk = zk; 
 13     } 
 14  
 15     /** 
 16      * 级联查看某节点下所有节点及节点值 
 17      * @throws Exception  
 18      * @throws KeeperException  
 19      */ 
 20     public static Map<String, String> getChildNodeAndValue(String path,ZooKeeper zk,Map<String, String> map) throws Exception{ 
 21          
 22         //看看传入的节点是否存在 
 23         if (zk.exists(path, false) != null) { 
 24             //存在的话将该节点的数据存放到map中，key是绝对路径，value是存放的数据 
 25             map.put(path, new String(zk.getData(path, false, null))); 
 26             //查看该节点下是否还有子节点 
 27             List<String> list = zk.getChildren(path, false); 
 28             if (list.size() != 0) { 
 29                 //遍历子节点,递归调用自身的方法 
 30                 for (String child : list) { 
 31                     getChildNodeAndValue( path + "/" + child,zk,map); 
 32                 } 
 33             } 
 34         } 
 35          
 36         return map; 
 37     } 
 38  
 39     /** 
 40      * 删除一个节点，不管有有没有任何子节点 
 41      */ 
 42     public static boolean rmr(String path, ZooKeeper zk) throws Exception { 
 43         //看看传入的节点是否存在 
 44         if((zk.exists(path, false)) != null) { 
 45             //查看该节点下是否还有子节点 
 46             List<String> children = zk.getChildren(path, false); 
 47             //如果没有子节点，直接删除当前节点 
 48             if(children.size() == 0) { 
 49                 zk.delete(path, -1); 
 50             }else { 
 51                 //如果有子节点，则先遍历删除子节点 
 52                 for(String child : children) { 
 53                     rmr(path+"/"+child,zk); 
 54                 } 
 55                 //删除子节点之后再删除之前子节点的父节点 
 56                 rmr(path,zk); 
 57             } 
 58             return true; 
 59         }else { 
 60             //如果传入的路径不存在直接返回不存在 
 61             System.out.println(path+" not exist"); 
 62             return false; 
 63         } 
 64          
 65          
 66      
 67     } 
 68  
 69     /** 
 70      * 级联创建任意节点 
 71      * create znodePath data 
 72      * create /a/b/c/xx 'xx' 
 73      * @throws Exception  
 74      * @throws KeeperException  
 75       
 76      */ 
 77     public static boolean createZNode(String znodePath, String data, ZooKeeper zk) throws Exception{ 
 78          
 79         //看看要创建的节点是否存在 
 80         if((zk.exists(znodePath, false)) != null) { 
 81             return false; 
 82         }else {         
 83             //获取父路径 
 84             String parentPath = znodePath.substring(0, znodePath.lastIndexOf("/")); 
 85             //如果父路径的长度大于0，则先创建父路径，再创建子路径 
 86             if(parentPath.length() > 0) { 
 87                 createZNode(parentPath, data, zk); 
 88                 zk.create(znodePath, data.getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT); 
 89             }else { 
 90                 //如果父路径的长度=0，则直接创建子路径 
 91                 zk.create(znodePath, data.getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT); 
 92             } 
 93             return true; 
 94         }     
 95     } 
 96  
 97     /** 
 98      * 清空子节点 
 99      */ 
100     public static boolean clearChildNode(String znodePath, ZooKeeper zk) throws Exception { 
101          
102         List<String> children = zk.getChildren(znodePath, false); 
103          
104         for (String child : children) {     
105             String childNode = znodePath + "/" + child;     
106             if (zk.getChildren(childNode, null).size() != 0) {     
107                 clearChildNode(childNode, zk);     
108             }     
109             zk.delete(childNode, -1);     
110         }     
111  
112         return true; 
113     } 
114 }