feat(database): 创建员工信息表并实现相关查询功能

- 创建员工信息表结构，包括 empnum、info、salary、performance 和 training列族
- 实现数据加载功能，从 emp.txt 文件中读取员工信息并插入表中- 添加员工信息查询功能，包括查询 ID 大于 7500 的员工、绩效大于4 且入职早于 2022 年的员工等
- 实现最近晋升员工和培训课程统计功能
- 添加 emp 表的字段名称说明文档

emp.txt

@@ -0,0 +1,14 @@
+7369,SMITH,CLERK,7902,2021-12-17,800,0,20,160,4,2024-06-01,"Java基础,SQL优化"
+7499,ALLEN,SALESMAN,7698,2021-02-20,1600,300,30,180,5,2024-09-15,"销售技巧,客户关系管理"
+7521,WARD,SALESMAN,7698,2021-02-22,1250,500,30,170,3,2025-03-10,"谈判技巧,市场分析"
+7566,JONES,MANAGER,7839,2021-04-02,2975,0,20,150,4,2024-07-01,"领导力培训,项目管理"
+7654,MARTIN,SALESMAN,7698,2021-09-28,1250,1400,30,190,5,2024-10-01,"销售策略,数据分析"
+7698,BLAKE,MANAGER,7839,2021-05-01,2850,0,30,140,4,2024-08-15,"团队建设,沟通技巧"
+7782,CLARK,MANAGER,7839,2021-06-09,2450,0,10,130,5,2024-05-01,"人力资源管理,绩效考核"
+7788,SCOTT,ANALYST,7566,2023-12-09,3000,0,20,165,4,2024-11-01,"数据分析,数据库优化"
+7839,KING,PRESIDENT,null,2021-11-17,5000,0,10,120,5,2024-04-01,"战略规划,企业治理"
+7844,TURNER,SALESMAN,7698,2021-09-08,1500,0,30,175,3,2024-02-15,"销售技巧,客户服务"
+7876,ADAMS,CLERK,7788,2024-01-12,1100,0,20,155,4,2025-01-01,"办公软件,文档处理"
+7900,JAMES,CLERK,7698,2021-12-03,950,0,30,145,3,2025-03-01,"客户服务,订单处理"
+7902,FORD,ANALYST,7566,2021-12-03,3000,0,20,170,5,2024-06-01,"数据分析,报告撰写"
+7934,MILLER,CLERK,7782,2023-01-23,1300,0,10,150,4,2024-07-01,"财务报表,预算管理"

emp表的字段名称.txt

@@ -0,0 +1,2 @@
+员工ID,姓名,职位,上司ID,入职时间,工资,奖金,部门ID，员工每月工作时长，绩效评分（1-5分），最近一次晋升日期，参加的培训课程列表
+empno,ename,job,mgr,hiredate,sal,credit,deptno,work_hours,performance_rating,promotion_date,training_courses

src/main/EmpHBaseClient.java

@@ -0,0 +1,141 @@
+// 创建职工表结构
+public void createEmpTable() throws IOException {
+    HBaseAdmin admin = new HBaseAdmin(conf);
+    if (admin.tableExists("emp1520")) {
+        System.out.println("Table already exists");
+        return;
+    }
+    HTableDescriptor tableDesc = new HTableDescriptor(TableName.valueOf("emp1520"));
+    tableDesc.addFamily(new HColumnDescriptor("empnum")); // 存储员工ID
+    tableDesc.addFamily(new HColumnDescriptor("info")); // 存储基本信息
+    tableDesc.addFamily(new HColumnDescriptor("salary")); // 存储薪资
+    tableDesc.addFamily(new HColumnDescriptor("performance")); // 存储绩效信息
+    tableDesc.addFamily(new HColumnDescriptor("training")); // 存储培训课程
+    admin.createTable(tableDesc);
+    admin.close();
+}
+
+// 插入数据实现
+public void loadData() throws IOException {
+    Table table = connection.getTable(TableName.valueOf("emp1520"));
+    try (BufferedReader br = new BufferedReader(new FileReader("emp.txt"))) {
+        String line;
+        while ((line = br.readLine()) != null) {
+            String[] fields = line.split(",");
+            String empno = fields[0];
+            String rowKey = generateRowKey(empno); // 生成MD5前缀+empno的RowKey
+            Put put = new Put(Bytes.toBytes(rowKey));
+            // empnum列族
+            put.addColumn(Bytes.toBytes("empnum"), Bytes.toBytes("empno"), Bytes.toBytes(empno));
+            // info列族
+            put.addColumn(Bytes.toBytes("info"), Bytes.toBytes("ename"), Bytes.toBytes(fields[1]));
+            put.addColumn(Bytes.toBytes("info"), Bytes.toBytes("job"), Bytes.toBytes(fields[2]));
+            put.addColumn(Bytes.toBytes("info"), Bytes.toBytes("mgr"), Bytes.toBytes(fields[3]));
+            put.addColumn(Bytes.toBytes("info"), Bytes.toBytes("hiredate"), Bytes.toBytes(fields[4]));
+            put.addColumn(Bytes.toBytes("info"), Bytes.toBytes("credit"), Bytes.toBytes(fields[5]));
+            // salary列族
+            put.addColumn(Bytes.toBytes("salary"), Bytes.toBytes("sal"), Bytes.toBytes(fields[6]));
+            // performance列族
+            put.addColumn(Bytes.toBytes("performance"), Bytes.toBytes("work_hours"), Bytes.toBytes(fields[7]));
+            put.addColumn(Bytes.toBytes("performance"), Bytes.toBytes("performance_rating"), Bytes.toBytes(fields[8]));
+            put.addColumn(Bytes.toBytes("performance"), Bytes.toBytes("promotion_date"), Bytes.toBytes(fields[9]));
+            // training列族
+            put.addColumn(Bytes.toBytes("training"), Bytes.toBytes("training_courses"), Bytes.toBytes(fields[10]));
+            table.put(put);
+        }
+    }
+}
+
+// RowKey生成方法
+private String generateRowKey(String empno) {
+    String prefix = empno.substring(0,3);
+    String md5 = md5Hash(prefix);
+    return md5.substring(0,4) + empno; // 前4位MD5+原empno
+}
+
+// MD5计算方法
+private static String md5Hash(String input) {
+    try {
+        MessageDigest md = MessageDigest.getInstance("MD5");
+        byte[] messageDigest = md.digest(input.getBytes());
+        BigInteger number = new BigInteger(1, messageDigest);
+        return number.toString(16);
+    } catch (NoSuchAlgorithmException e) {
+        throw new RuntimeException(e);
+    }
+}
+
+// 查询ID>7500的员工
+public void queryEmpNoOver7500() throws IOException {
+    Scan scan = new Scan();
+    Filter filter = new SingleColumnValueFilter(
+            Bytes.toBytes("empnum"),
+            Bytes.toBytes("empno"),
+            CompareFilter.CompareOp.GREATER_OR_EQUAL,
+            new SubstringComparator("7500")
+    );
+    scan.setFilter(filter);
+    ResultScanner scanner = table.getScanner(scan);
+    for (Result result : scanner) {
+        // 输出结果处理
+    }
+}
+
+// 绩效>4且入职早于2022年
+public void queryPerformanceAndHiredate() throws IOException {
+    FilterList list = new FilterList(FilterList.Operator.MUST_PASS_ALL);
+    list.addFilter(new SingleColumnValueFilter(
+            Bytes.toBytes("performance"),
+            Bytes.toBytes("performance_rating"),
+            CompareFilter.CompareOp.GREATER_OR_EQUAL,
+            new SubstringComparator("5")
+    ));
+    list.addFilter(new SingleColumnValueFilter(
+            Bytes.toBytes("info"),
+            Bytes.toBytes("hiredate"),
+            CompareFilter.CompareOp.LESS,
+            new SubstringComparator("2022-01-01")
+    ));
+    Scan scan = new Scan();
+    scan.setFilter(list);
+    ResultScanner scanner = table.getScanner(scan);
+    // 结果处理逻辑
+}
+
+// 最近晋升员工查询
+public void findLatestPromotion() throws IOException {
+    Scan scan = new Scan();
+    ResultScanner scanner = table.getScanner(scan);
+    List<PromotionRecord> records = new ArrayList<>();
+    for (Result result : scanner) {
+        String promotionDateStr = Bytes.toString(
+                result.getValue(Bytes.toBytes("performance"), Bytes.toBytes("promotion_date"))
+        );
+        if (promotionDateStr != null) {
+            records.add(new PromotionRecord(
+                    Bytes.toString(result.getRow()),
+                    LocalDate.parse(promotionDateStr)
+            ));
+        }
+    }
+    records.sort(Comparator.comparing(PromotionRecord::getDate).reversed());
+    // 输出最新记录
+}
+
+// 培训课程统计
+public void countTrainingCourses() throws IOException {
+    Map<String, Integer> courseMap = new HashMap<>();
+    Scan scan = new Scan();
+    ResultScanner scanner = table.getScanner(scan);
+    for (Result result : scanner) {
+        String coursesStr = Bytes.toString(
+                result.getValue(Bytes.toBytes("training"), Bytes.toBytes("training_courses"))
+        );
+        if (coursesStr != null) {
+            for (String course : coursesStr.split(",")) {
+                courseMap.put(course, courseMap.getOrDefault(course, 0)+1);
+            }
+        }
+    }
+    // 输出统计结果
+}