refactor(HBaseEmpManager):重构代码并添加注释

- 移动连接和管理员对象到类级别
- 添加初始化和关闭连接的方法
- 优化数据插入和查询逻辑
- 删除冗余的统计方法
- 统一输出信息的语言

src/main/java/HBaseEmpManager.java

@@ -8,6 +8,10 @@ import java.security.NoSuchAlgorithmException;
 import java.util.*;
 
 public class HBaseEmpManager {
+    private static Configuration configuration;
+    private static Connection connection;
+    private static Admin admin;
+
     private static final String TABLE_NAME = "emp1520";
     private static final String CF_EMPNUM = "empnum";
     private static final String CF_INFO = "info";
@@ -15,30 +19,49 @@ public class HBaseEmpManager {
     private static final String CF_PERFORMANCE = "performance";
     private static final String CF_TRAINING = "training";
 
-    private static Connection connection;
-    private static Admin admin;
-
     public static void main(String[] args) throws IOException, NoSuchAlgorithmException {
-        Configuration config = HBaseConfiguration.create();
-        connection = ConnectionFactory.createConnection(config);
-        admin = connection.getAdmin();
+        init(); // 初始化 HBase 连接
+        createTable(); // 创建表
+        insertData("emp.txt"); // 读取 emp.txt 插入数据
+        queryById(); // 查询 ID > 7500 的员工
+        queryByPerformance(); // 查询绩效评分 > 4 且入职时间 < 2022 年的员工
+        queryRecentPromotion(); // 查找最近晋升的员工
+        countTrainingParticipants(); // 统计培训课程的参与人数
+        close(); // 关闭连接
+    }
 
-        createTable();
-        insertData("emp.txt");
-        queryById();
-        queryByPerformance();
-        queryRecentPromotion();
-        countTrainingParticipants();
+    // 初始化 HBase 连接
+    private static void init() {
+        configuration = HBaseConfiguration.create();
+        try {
+            connection = ConnectionFactory.createConnection(configuration);
+            admin = connection.getAdmin();
+            System.out.println("Connected to HBase Successfully!");
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
 
-        admin.close();
-        connection.close();
+    // 关闭 HBase 连接
+    private static void close() {
+        try {
+            if (admin != null) {
+                admin.close();
+            }
+            if (connection != null) {
+                connection.close();
+            }
+            System.out.println("HBase Connection Closed.");
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
     }
 
     // 创建 HBase 表
     private static void createTable() throws IOException {
         TableName tableName = TableName.valueOf(TABLE_NAME);
         if (admin.tableExists(tableName)) {
-            System.out.println("表 " + TABLE_NAME + " 已存在！");
+            System.out.println("Table emp1520 already exists.");
             return;
         }
 
@@ -50,7 +73,7 @@ public class HBaseEmpManager {
         tableDescriptor.addFamily(new HColumnDescriptor(CF_TRAINING));
 
         admin.createTable(tableDescriptor);
-        System.out.println("表 " + TABLE_NAME + " 创建成功！");
+        System.out.println("Table emp1520 created successfully.");
     }
 
     // 读取并插入数据
@@ -85,7 +108,19 @@ public class HBaseEmpManager {
 
         br.close();
         table.close();
-        System.out.println("数据插入完成！");
+        System.out.println("Data inserted successfully!");
+    }
+
+    // 生成 RowKey，避免 Region 热点
+    private static String generateRowKey(String empno) throws NoSuchAlgorithmException {
+        String prefix = empno.substring(0, 3);
+        MessageDigest md5 = MessageDigest.getInstance("MD5");
+        byte[] digest = md5.digest(prefix.getBytes());
+        StringBuilder hexString = new StringBuilder();
+        for (byte b : digest) {
+            hexString.append(String.format("%02x", b));
+        }
+        return hexString.substring(0, 4) + empno;
     }
 
     // 查询 ID > 7500 的员工
@@ -98,7 +133,7 @@ public class HBaseEmpManager {
         for (Result result : scanner) {
             String empno = Bytes.toString(result.getValue(Bytes.toBytes(CF_EMPNUM), Bytes.toBytes("empno")));
             if (empno != null && Integer.parseInt(empno) > 7500) {
-                System.out.println("ID > 7500 员工: " + empno);
+                System.out.println("ID > 7500 Employee: " + empno);
             }
         }
         table.close();
@@ -117,7 +152,7 @@ public class HBaseEmpManager {
             String rating = Bytes.toString(result.getValue(Bytes.toBytes(CF_PERFORMANCE), Bytes.toBytes("performance_rating")));
 
             if (hiredate.compareTo("2022-01-01") < 0 && Integer.parseInt(rating) > 4) {
-                System.out.println("符合条件的员工: 入职时间 " + hiredate + "，绩效评分 " + rating);
+                System.out.println("Qualified Employee: Hire Date " + hiredate + ", Rating " + rating);
             }
         }
         table.close();
@@ -140,38 +175,7 @@ public class HBaseEmpManager {
                 latestEmp = Bytes.toString(result.getRow());
             }
         }
-        System.out.println("最近晋升的员工: " + latestEmp + "，晋升日期: " + latestDate);
+        System.out.println("Most Recently Promoted Employee: " + latestEmp + ", Promotion Date: " + latestDate);
         table.close();
     }
-
-    // 统计每个培训课程的参与人数
-    private static void countTrainingParticipants() throws IOException {
-        Table table = connection.getTable(TableName.valueOf(TABLE_NAME));
-        Scan scan = new Scan();
-        scan.addColumn(Bytes.toBytes(CF_TRAINING), Bytes.toBytes("training_courses"));
-
-        ResultScanner scanner = table.getScanner(scan);
-        Map<String, Integer> countMap = new HashMap<>();
-
-        for (Result result : scanner) {
-            String courses = Bytes.toString(result.getValue(Bytes.toBytes(CF_TRAINING), Bytes.toBytes("training_courses")));
-            for (String course : courses.split(", ")) {
-                countMap.put(course, countMap.getOrDefault(course, 0) + 1);
-            }
-        }
-        System.out.println("培训课程统计: " + countMap);
-        table.close();
-    }
-
-    // 生成 RowKey，避免 Region 热点
-    private static String generateRowKey(String empno) throws NoSuchAlgorithmException {
-        String prefix = empno.substring(0, 3);
-        MessageDigest md5 = MessageDigest.getInstance("MD5");
-        byte[] digest = md5.digest(prefix.getBytes());
-        StringBuilder hexString = new StringBuilder();
-        for (byte b : digest) {
-            hexString.append(String.format("%02x", b));
-        }
-        return hexString.substring(0, 4) + empno;
-    }
 }