1. //EmpReader.java
    2. package edu.hue.jk.io;
    4. import java.io.BufferedReader;
    5. import java.io.File;
    6. import java.io.FileNotFoundException;
    7. import java.io.FileReader;
    8. import java.io.IOException;
    9. import java.sql.Date;
    10. import java.util.Collection;
    11. import java.util.HashMap;
    13. import edu.hue.jk.bean.Emp;
    15. public class EmpReader {
    16.     public HashMap<Integer, Emp> read(File inFile) {
    17.         HashMap<Integer, Emp> empMap = new HashMap<>();
    18.         BufferedReader reader = null;
    19.         String line;
    20.         try {
    21.             reader = new BufferedReader(new FileReader(inFile));
    22.             reader.readLine();    //跳过第一行
    24.             String[] items;
    25.             Emp emp;
    26.             while ((line = reader.readLine()) != null) {
    27.                 //使用item=line.split("\t")；将读入的数据行按照制表符切割成一组字符串数组
    28.                 items = line.split("\t");
    30.                 Integer empno = Integer.parseInt(items[0]);
    31.                 String ename = items[1];
    32.                 String job = items[2];
    33.                 Integer mgr = items[3].equals("") ? null : Integer.parseInt(items[3]);
    34.                 Date hiredate = Date.valueOf(items[4]);
    35.                 Double sal = items[5].equals("") ? null : Double.parseDouble(items[5]);
    36.                 Double comm = items[6].equals("") ? null : Double.parseDouble(items[6]);
    37.                 Integer deptno = items[7].equals("") ? null : Integer.parseInt(items[7]);
    39.                 emp = new Emp(empno, ename, job, mgr, hiredate, sal, comm, deptno);
    41.                 empMap.put(empno, emp);
    42.             }
    43.         } catch (FileNotFoundException e) {
    44.             // TODO Auto-generated catch block
    45.             e.printStackTrace();
    46.         } catch (IOException e) {
    47.             // TODO Auto-generated catch block
    48.             e.printStackTrace();
    49.         } finally {
    50.             if (reader != null) {
    51.                 try {
    52.                     reader.close();
    53.                 } catch (IOException e) {
    54.                     // TODO Auto-generated catch block
    55.                     e.printStackTrace();
    56.                 }
    57.             }
    58.         }
    60.         return empMap;
    61.     }
    63.     public static void main(String[] args) {
    64.         File inFile = new File("etc/emp.txt");
    65.         EmpReader reader = new EmpReader();
    66.         HashMap<Integer, Emp> empMap = reader.read(inFile);
    68.         Collection<Emp> empSet = empMap.values();
    69.         for (Emp e : empSet) {
    70.             System.out.println(e);
    71.         }
    72.     }
    73. }
    1. //DeptReader.java
    2. package edu.hue.jk.io;
    4. import java.io.BufferedReader;
    5. import java.io.File;
    6. import java.io.FileNotFoundException;
    7. import java.io.FileReader;
    8. import java.io.IOException;
    9. import java.util.Collection;
    10. import java.util.HashMap;
    12. import edu.hue.jk.bean.Dept;
    14. public class DeptReader {
    15.     public HashMap<Integer, Dept> read(File inFile) {
    16.         HashMap<Integer, Dept> deptMap = new HashMap<>();
    17.         BufferedReader reader = null;
    18.         String line;
    19.         try {
    20.             reader = new BufferedReader(new FileReader(inFile));
    21.             reader.readLine();
    23.             String[] items;
    24.             Dept dept;
    25.             while ((line = reader.readLine()) != null) {
    26.                 items = line.split("\t");
    28.                 Integer deptno = Integer.parseInt(items[0]);
    29.                 String dname = items[1];
    30.                 String loc = items[2];
    32.                 dept = new Dept(deptno, dname, loc);
    34.                 deptMap.put(deptno, dept);
    35.             }
    36.         } catch (FileNotFoundException e) {
    37.             e.printStackTrace();
    38.         } catch (IOException e) {
    39.             e.printStackTrace();
    40.         } finally {
    41.             if (reader != null) {
    42.                 try {
    43.                     reader.close();
    44.                 } catch (IOException e) {
    45.                     e.printStackTrace();
    46.                 }
    47.             }
    48.         }
    50.         return deptMap;
    51.     }
    53.     public static void main(String[] args) {
    54.         File inFile = new File("etc/dept.txt");
    55.         DeptReader reader = new DeptReader();
    56.         HashMap<Integer, Dept> deptMap = reader.read(inFile);
    58.         Collection<Dept> deptSet = deptMap.values();
    59.         for (Dept e : deptSet) {
    60.             System.out.println(e);
    61.         }
    62.     }
    63. }
    1. //MainApp.java
    2. package edu.hue.jk.dao;
    4. import java.io.File;
    5. import java.sql.Date;
    6. import java.util.HashMap;
    8. import edu.hue.jk.bean.Dept;
    9. import edu.hue.jk.bean.Emp;
    10. import edu.hue.jk.io.DeptReader;
    11. import edu.hue.jk.io.EmpReader;
    13. public class MainApp {
    15.     public static void main(String[] args) {
    16.         File empinFile = new File("etc/emp.txt");
    17.         EmpReader empreader = new EmpReader();
    18.         HashMap<Integer, Emp> empMap = empreader.read(empinFile);
    20.         File deptinFile = new File("etc/dept.txt");
    21.         DeptReader deptreader = new DeptReader();
    22.         HashMap<Integer, Dept> deptMap = deptreader.read(deptinFile);
    24.         System.out.println("DEPT_NAME\tEMPLPYEE");
    25.         for (Emp e : empMap.values()) {
    26.             if (e.getComm()==null && 
    27.                 (e.getSal()<2000 || 
    28.                  e.getHiredate().compareTo(Date.valueOf("1981-05-01"))>=0 && 
    29.                  e.getHiredate().compareTo(Date.valueOf("1981-11-30"))<=0)) {
    31.                 Integer deptno = e.getDeptno();
    33.                 Dept dept = deptMap.get(deptno);
    35.                 System.out.println(dept.getDname() + "\t" + e.getEname());
    36.             }
    37.         }
    38.     }
    40. }
    1. //EmpDeptVO.java
    2. package edu.hue.jk.dao;
    4. public class EmpDeptVO implements Comparable<EmpDeptVO> {
    5.     private String deptt;
    6.     private Integer count;
    8.     public EmpDeptVO(String deptt, Integer count) {
    9.         super();
    10.         this.deptt = deptt;
    11.         this.count = count;
    12.     }
    14.     public String getDeptt() {
    15.         return deptt;
    16.     }
    18.     public void setDeptt(String deptt) {
    19.         this.deptt = deptt;
    20.     }
    22.     public Integer getCount() {
    23.         return count;
    24.     }
    26.     public void setCount(Integer count) {
    27.         this.count = count;
    28.     }
    30.     @Override
    31.     public String toString() {
    32.         return "EmpDeptVO [deptt=" + deptt + ", count=" + count + "]";
    33.     }
    35.     @Override
    36.     public int compareTo(EmpDeptVO o) {
    37.         // this为当前对象，o为目标对象，比较两者count，实现降序排列
    38.         return (this.getCount()-o.getCount()) * -1;
    39.     }
    40. }
    1. //MainApp2.java
    2. package edu.hue.jk.dao;
    4. import java.io.File;
    5. import java.sql.Date;
    6. import java.util.ArrayList;
    7. import java.util.Arrays;
    8. import java.util.HashMap;
    9. import java.util.List;
    11. import edu.hue.jk.bean.Dept;
    12. import edu.hue.jk.bean.Emp;
    13. import edu.hue.jk.io.DeptReader;
    14. import edu.hue.jk.io.EmpReader;
    16. public class MainApp2 {
    17.     public static void main(String[] args) {
    18.         File empinFile = new File("etc/emp.txt");
    19.         EmpReader empreader = new EmpReader();
    20.         HashMap<Integer, Emp> empMap = empreader.read(empinFile);
    22.         File deptinFile = new File("etc/dept.txt");
    23.         DeptReader deptreader = new DeptReader();
    24.         HashMap<Integer, Dept> deptMap = deptreader.read(deptinFile);
    26.         HashMap<String, List<Emp>> data = new HashMap<>();
    28.         for (Emp emp : empMap.values()) {
    30.             if (emp.getComm()==null && (emp.getSal()<2000 || emp.getHiredate().compareTo(Date.valueOf("1981-05-01"))>=0 && emp.getHiredate().compareTo(Date.valueOf("1981-11-30"))<=0)) {
    31.                 Integer deptno = emp.getDeptno();
    33.                 Dept dept = deptMap.get(deptno);
    34.                 if (data.containsKey(dept.getDname())) {
    35.                     List<Emp> empList = data.get(dept.getDname());
    36.                     empList.add(emp);
    37.                 } else {
    38.                     List<Emp> empList = new ArrayList<Emp>();
    39.                     empList.add(emp);
    40.                     data.put(dept.getDname(), empList);
    41.                 }
    42.             }
    43.         }
    45.         List<EmpDeptVO> voList = new ArrayList<EmpDeptVO>();
    46.         for (String Dept : data.keySet()) {
    47.             voList.add(new EmpDeptVO(Dept, data.get(Dept).size()));
    48.         }
    50.         Object[] outList = voList.toArray();
    51.         Arrays.sort(outList);
    52.         System.out.println("DEPT_NAME" + "\t" + "total");
    53.         for (Object vo : outList) {
    54.             System.out.println(((EmpDeptVO)vo).getDeptt() + "\t" + ((EmpDeptVO)vo).getCount());
    55.         }
    57.     }
    58. }
    1. //emp.txt
    2. EMPNO    ENAME    JOB    MGR    HIREDATE    SAL    COMM    DEPTNO
    3. 7369    SMITH    CLERK    7902    1980-12-17    800        20
    4. 7499    ALLEN    SALESMAN    7698    1981-02-20    1600    300    30
    5. 7521    WARD    SALESMAN    7698    1981-02-22    1250    500    30
    6. 7566    JONES    MANAGER    7839    1981-04-02    2975        20
    7. 7654    MARTIN    SALESMAN    7698    1981-09-28    1250    1400    30
    8. 7698    BLAKE    MANAGER    7839    1981-05-01    2850        30
    9. 7782    CLARK    MANAGER    7839    1981-06-09    2450        10
    10. 7839    KING    PRESIDENT        1981-11-17    5000        10
    11. 7844    TURNER    SALESMAN    7698    1981-09-08    1500    0    30
    12. 7900    JAMES    CLERK    7698    1981-12-03    950        30
    13. 7902    FORD    ANALYST    7566    1981-12-03    3000        20
    14. 7934    MILLER    CLERK    7782    1982-01-23    1300        10
    1. //DEPT.txt
    2. DEPTNO    DNAME    LOC
    3. 10    ACCOUNTING    NEW YORK
    4. 20    RESEARCH    DALLAS
    5. 30    SALES    CHICAGO
    6. 40    OPERATIONS    BOSTON

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