员工管理系统（集合与IO流的结合使用 beta2.0 ObjectInputStream/ ObjectOutputStream）

 1 package cn.employee;
 2 
 3 import java.io.Serializable;
 4 
 5 public class Employee implements Serializable{
 6     private static final long serialVersionUID = 1L;
 7     private int empNo;
 8     private String name;
 9     private String department;
10 
11     public Employee() {
12         super();
13     }
14 
15     public Employee(int empNo, String name, String department) {
16         super();
17         this.empNo = empNo;
18         this.name = name;
19         this.department = department;
20     }
21 
22     public int getEmpNo() {
23         return empNo;
24     }
25 
26     public void setEmpNo(int empNo) {
27         this.empNo = empNo;
28     }
29 
30     public String getName() {
31         return name;
32     }
33 
34     public void setName(String name) {
35         this.name = name;
36     }
37 
38     public String getDepartment() {
39         return department;
40     }
41 
42     public void setDepartment(String department) {
43         this.department = department;
44     }
45 
46     public int hashCode() {
47         final int prime = 31;
48         int result = 1;
49         result = prime * result
50                 + ((department == null) ? 0 : department.hashCode());
51         result = prime * result + empNo;
52         result = prime * result + ((name == null) ? 0 : name.hashCode());
53         return result;
54     }
55 
56     public String toString() {
57         return "Employee [empNo=" + empNo + ", name=" + name + ", department="
58                 + department + "]";
59     }
60 
61 }

Employee

 1 package cn.employee;
 2 
 3 import java.util.List;
 4 
 5 public class EmpUtils {
 6     
 7     /**
 8      * 是否有相同的员工编号
 9      */
10     public static boolean copy(List<Employee> list,int empNo){
11         boolean flag = false;
12         for (int i = 0; i < list.size(); i++) {
13             if(list.get(i).getEmpNo()==empNo){
14                 flag=true;
15                 break;
16             }            
17         }
18         return flag;
19     }
20     
21     /**
22      * 添加员工
23      */
24     public static boolean add(List<Employee> list, Employee e) {
25         if (list.contains(e)) {
26             System.out.println("有重复的员工");
27             return false;
28         } 
29         return list.add(e);
30     }
31 
32     /**
33      * 查询所有员工
34      */
35     public static void querys(List<Employee> list) {
36         for (int i = 0; i < list.size(); i++) {
37             System.out.println(list.get(i));
38         }
39     }
40 
41     /**
42      * 查询指定员工
43      */
44     public static void query(List<Employee> list,int empNo){
45         for(int i=0;i<list.size();i++){
46             if(list.get(i).getEmpNo()==empNo){
47                 System.out.println(list.get(i));
48                 break;
49             }
50             if((i==list.size()-1)&&list.get(i).getEmpNo()!=empNo){
51                 System.out.println("不存在该员工！");
52             }
53         }    
54     }
55     /**
56      * 删除员工
57      */
58     public static void delete(List<Employee> list,int empNo){
59         for(int i=0;i<list.size();i++){
60             if(list.get(i).getEmpNo()==empNo){
61                 list.remove(list.get(i));                
62                 System.out.println("删除成功！");
63                 break;
64             }
65             if((i==list.size()-1)&&list.get(i).getEmpNo()!=empNo){
66                 System.out.println("删除失败！");
67             }
68         }
69     }
70     /**
71      * 修改员工
72      */
73     public static void update(List<Employee> list,int empNo,String name,String department){
74         for (Employee e : list) {
75             if(e.getEmpNo()==empNo){
76                 e.setName(name); 
77                 e.setDepartment(department);
78                 System.out.println("修改成功！");
79                 break;
80             }
81         }
82     }
83 }

EmpUtils

  1 package cn.employee;
  2 
  3 import java.io.File;
  4 import java.io.FileInputStream;
  5 import java.io.FileNotFoundException;
  6 import java.io.FileOutputStream;
  7 import java.io.IOException;
  8 import java.io.ObjectInputStream;
  9 import java.io.ObjectOutputStream;
 10 import java.io.OutputStream;
 11 import java.util.ArrayList;
 12 import java.util.List;
 13 import java.util.Scanner;
 14 
 15 public class MyEmployee {
 16     Scanner sc = new Scanner(System.in);
 17     List<Employee> list = null;
 18     int empNo;
 19     String name;
 20     String department;
 21     int num = 0;
 22     boolean flag = false;
 23     File file = null;
 24     FileOutputStream fos=null;
 25     ObjectInputStream ois = null;
 26     ObjectOutputStream oos = null;
 27 
 28     public MyEmployee() throws FileNotFoundException, IOException,
 29             ClassNotFoundException {
 30         list = new ArrayList<Employee>();
 31         fun(list);
 32     }
 33 
 34     public void fun(List<Employee> list) throws FileNotFoundException,
 35             IOException, ClassNotFoundException {
 36         ok: for (;;) {
 37             printOptions();
 38             num = sc.nextInt();
 39 
 40             if (num < 1 || num > 6) {
 41                 System.out.println("输入有误，将重新开始选择！");
 42                 break ok;
 43             }
 44 
 45             switch (num) {
 46             case 1:
 47                 printEmpNo();
 48                 if (!EmpUtils.copy(list, empNo)) {
 49                     printName();
 50                     if (EmpUtils.add(list,
 51                             new Employee(empNo, name, department))) {
 52                         addObject(list);//
 53                         System.out.println("添加成功！");
 54                     }
 55                 } else {
 56                     System.out.println("添加失败！");
 57                 }
 58                 break;
 59             case 2:
 60                 // EmpUtils.querys(list);
 61                 list=queryAllObject();
 62 //                System.out.println(list); 
 63                 break;
 64             case 3: 
 65 //                System.out.println("3333   "+list); 
 66                 printEmpNo();
 67                 EmpUtils.query(list, empNo);
 68                 break;
 69             case 4:
 70                 printEmpNo();
 71                 EmpUtils.delete(list, empNo);
 72 //                System.out.println(list); 
 73                 addObject(list);
 74                 break;
 75             case 5:
 76                 printEmpNo();
 77                 if (EmpUtils.copy(list, empNo)) {// 有该员工
 78                     printName();
 79                     EmpUtils.update(list, empNo, name, department);
 80                 }
 81                 addObject(list);
 82                 break;
 83             case 6:
 84                 flag = true;
 85             }
 86 
 87             if (flag) {// 退出
 88                 break;
 89             }
 90         }
 91     }
 92 
 93     public void printOptions() {
 94         System.out.println("***员工管理系统***");
 95         System.out.println("1.添加员工");
 96         System.out.println("2.查询所有员工");
 97         System.out.println("3.查询员工");
 98         System.out.println("4.删除员工");
 99         System.out.println("5.修改员工");
100         System.out.println("6.退出");
101         System.out.println("请输入你要进行的操作：");
102     }
103 
104     public void printEmpNo() {
105         System.out.println("请输入员工编号：");
106         empNo = sc.nextInt();
107     }
108 
109     public void printName() {
110         System.out.println("请输入员工姓名：");
111         name = sc.next();
112         System.out.println("请输入员工部门：");
113         department = sc.next();
114     }
115 
116     /**
117      * 在向一个文件写入可序列化对象时，每次只想向文件的末尾添加一个可序列化的对象，于是使用了FileOutputStream（文件名，true）
118      * 间接的构建了ObjectOutputStream流对象
119      * ，在向外读数据的时候第一次运行的时候不会报错，在第二次就会报java.io.StreamCorruptedException: invalid
120      * type code: AC错误
121      * 
122      * 在一个文件都有一个文件的头部和文件体。由于对多次使用FileOutputStream（文件名，true）
123      * 构建的ObjectOutputStream对象向同一个文件写数据
124      * ，在每次些数据的时候他都会向这个文件末尾先写入header在写入你要写的对象数据，在读取的时候遇到这个在文件体中的header就会报错
125      * 。导致读出时，出现streamcorrput异常。
126      * 
127      * 解决办法：所以这里要判断是不是第一次写文件，若是则写入头部，否则不写入。
128      * 
129      * @param list
130      * @throws FileNotFoundException
131      * @throws IOException
132      */
133     public void addObject(List<Employee> list) throws FileNotFoundException, IOException {
134         file = new File("src/cn/employee/emp.txt");
135 //        fos=new FileOutputStream(file,true);
136         fos=new FileOutputStream(file);
137         if (file.length() < 1) {// 判断文件大小并调用不同的方法
138             oos = new ObjectOutputStream(fos);
139         } else {
140             oos = new MyObjectOutputStream(fos);
141         }
142         oos.writeObject(list);
143         oos.flush();
144         oos.close();
145     }
146 
147     @SuppressWarnings("unchecked")
148     public List<Employee> queryAllObject() throws FileNotFoundException, IOException,
149             ClassNotFoundException {
150         ois = new ObjectInputStream(new FileInputStream(
151                 "src/cn/employee/emp.txt"));
152         List<Employee> list2=new ArrayList<Employee>();
153         list2 = (ArrayList<Employee>) ois.readObject();
154 
155         for (int i = 0; i < list2.size(); i++) {
156             System.out.println(list2.get(i));
157         }
158 
159         ois.close();
160         return list2;
161     }
162 }
163 
164 /*class MyObjectOutputStream extends ObjectOutputStream {
165     public MyObjectOutputStream() throws IOException {
166         super();
167     }
168 
169     public MyObjectOutputStream(OutputStream out) throws IOException {
170         super(out);
171     }
172 
173     @Override
174     protected void writeStreamHeader() throws IOException {
175         return;
176     }
177 }*/

MyEmployee

 1 package cn.employee;
 2 
 3 import java.io.IOException;
 4 import java.io.ObjectOutputStream;
 5 import java.io.OutputStream;
 6 
 7 public class MyObjectOutputStream extends ObjectOutputStream {
 8     public MyObjectOutputStream() throws IOException {
 9         super();
10     }
11 
12     public MyObjectOutputStream(OutputStream out) throws IOException {
13         super(out);
14     }
15 
16     @Override
17     protected void writeStreamHeader() throws IOException {
18         return;
19     }
20 }

MyObjectOutputStream

 1 package cn.employee;
 2 
 3 import java.io.FileNotFoundException;
 4 import java.io.IOException;
 5 
 6 /**
 7  * 员工管理系统
 8  * @author 王恒
 9  * @time 2016年10月19日 下午8:54:14
10  */
11 public class TestEmp {
12 
13     @SuppressWarnings("unused")
14     public static void main(String[] args) throws FileNotFoundException, IOException, ClassNotFoundException,NullPointerException {
15         
16         MyEmployee a=new MyEmployee();
17         
18     }
19 }

TestEmp