feat: 添加 TableExist 类用于检查 HBase 表是否存在

- 新增 TableExist 类，包含主方法和初始化、关闭连接的方法
- 通过用户输入表名，判断表是否存在并输出结果
- 使用 HBaseConfiguration 和 ConnectionFactory 实现连接
- 添加异常处理和资源关闭逻辑

src/main/java/TableExist.java

@@ -0,0 +1,52 @@
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.*;
+import org.apache.hadoop.hbase.client.*;
+import java.io.IOException;
+import java.util.Scanner;
+public class TableExist{
+    public static Configuration configuration;
+    public static Connection connection;
+    public static Admin admin;
+    public static void main(String[] args)throws IOException{
+
+        Scanner sc = new Scanner(System.in);
+        System.out.print("tableName:");
+        String tableName = sc.next();
+        init();
+
+        TableName tn = TableName.valueOf(tableName);
+        if(admin.tableExists(tn)) {
+            System.out.println("table " + tableName + " does exist!");
+        } else {
+            System.out.println("table " + tableName + " don't exist!");
+        }
+        close();
+    }
+    //建立连接
+    public static void init(){
+        //根据 hbase-site.xml文件初始化Configuration 对象
+        configuration  = HBaseConfiguration.create();
+        try{
+            //根据 Configuration对象初始化Connection 对象
+            connection = ConnectionFactory.createConnection(configuration);
+            //获取Admin 对象实例
+            admin = connection.getAdmin();
+        }catch (IOException e){
+            e.printStackTrace();
+        }
+        System.out.println("Connect to HBase successfully!");
+    }
+    //关闭连接
+    public static void close(){
+        try{
+            if(admin != null){
+                admin.close();
+            }
+            if(null != connection){
+                connection.close();
+            }
+        }catch (IOException e){
+            e.printStackTrace();
+        }
+    }
+}