考试系统（未完成的小程序）

  

系统组成：

1、用于封装get和set（name，idcard，grade，examid，location）方法的test_system包

2、用于封装add，delect和find方法的deo包

3、用于封装用户不存在的自定义异常类exception包

4、用于封装测试各类方法的test测试包

5、用于封装和用户打交道的UI界面包

6、用于封装（getdocument方法和把更改操作更新到xml文档中的方法）的utils工具包

7、用于充当数据库的xml文件

 总结：用deo包封装了增、删、查方法，其中在增删查方法里用到了utils包里document方法（获取标签等）以及更新（更改xml文件）方法，另外还会出现一些异常，所以自定义了一个异常包。

       

 1 <?xml version="1.0" encoding="UTF-8" standalone="no"?><exam>//建一个xml文档，充当数据库
 2     <student examid="4356" idcard="1234">
 3         <name>aa</name>
 4         <locationg>沈阳</locationg>
 5         <grade>89</grade>
 6     </student>
 7 
 8 <student examid="3434" idcard="45656">
 9     <name>dfdf</name>
10     <location>dgerg</location>
11     <grade>67.0</grade>
12     
13 </student>
14 <student examid="7890" idcard="123">
15     <name>heeh</name>
16     <location>345</location>
17     <grade>44.0</grade>
18     
19     </student>
20  
21   </exam>
 1 package test_system;
 2 //封装get和set方法
 3 public class student {
 4     
 5     private String idcard;
 6     private String examid;
 7     private String name;
 8     private String location;
 9     private double grade;
10     public String getIdcard()
11     {
12         return idcard;
13     }
14     public void setIdcard(String idcard)
15     {
16         this.idcard=idcard;
17     }
18     public String getExamid()
19     {
20         return examid;
21     }
22     public void setExamid(String examid)
23     {
24         this.examid=examid;
25     }
26     public String getLocation()
27     {
28         return location;
29     }
30     public void setLocation(String location)
31     {
32         this.location=location;
33     }
34     public String getName()
35     {
36         return name;
37     }
38     public void setName(String name)
39     {
40         this.name=name;
41     }
42     public double getGrade()
43     {
44         return grade;
45     }
46     public void setGrade(  double grade)
47     {
48         this.grade=grade;
49     }
50 }
  1 package test_system.deo;
  2 
  3 //具体封装add方法，delect方法和find方法
  4 
  5 import java.rmi.StubNotFoundException;
  6 
  7 import org.w3c.dom.Document;
  8 import org.w3c.dom.Element;
  9 import org.w3c.dom.NodeList;
 10 
 11 import test_system.student;
 12 import test_system.exception.StudentNotException;
 13 import test_system.utils.xmlutils;
 14 
 15 public class studentdeo {
 16 
 17     public void add(student s)
 18     {
 19         try {
 20             Document document= xmlutils.getDocument();
 21             //创建出封装学生信息的标签
 22             Element student_tag=document.createElement("student");
 23             student_tag.setAttribute("idcard", s.getIdcard());
 24             student_tag.setAttribute("examid", s.getExamid());
 25             //创建用于封装学生姓名、成绩和所在地的标签
 26             Element name=document.createElement("name");
 27             Element location=document.createElement("location");
 28             Element grade=document.createElement("grade");
 29             name.setTextContent(s.getName());
 30             location.setTextContent(s.getLocation());
 31             grade.setTextContent(s.getGrade()+"");
 32             student_tag.appendChild(name);
 33             student_tag.appendChild(location);
 34             student_tag.appendChild(grade);
 35             //把封装了学生信息的标签挂到文档上
 36             document.getElementsByTagName("exam").item(0).appendChild(student_tag);
 37             //更新内存
 38             xmlutils.writetoxml(document);
 39             
 40             
 41         } catch (Exception e) {
 42             throw new RuntimeException(e);//此处的异常，不能直接抛给上一级，因为没有意义，又不能打印，因为只能转型成运行异常！
 43         }
 44     }
 45     public student find(String examid)
 46     {
 47         try {
 48             Document document=xmlutils.getDocument();
 49             NodeList list=document.getElementsByTagName("student");
 50             for(int i=0;i<list.getLength();i++)
 51             {
 52                 Element stdent_tag=(Element) list.item(i);
 53                 if(stdent_tag.getAttribute("examid").equals(examid))
 54                 {
 55                     student s=new student();
 56                     s.setExamid(examid);
 57                     s.setIdcard(stdent_tag.getAttribute("idcard"));
 58                     s.setName(stdent_tag.getElementsByTagName("name").item(0).getTextContent());
 59                     s.setLocation(stdent_tag.getElementsByTagName("location").item(0).getTextContent());
 60                     s.setGrade(Double.parseDouble(stdent_tag.getElementsByTagName("grade").item(0).getTextContent()));
 61                     return s;
 62                     
 63                 }
 64                 return null;
 65             }
 66             
 67             
 68         } catch (Exception e) {
 69             throw new RuntimeException();
 70         }
 71         return null;
 72     }
 73     public void delect(String name) throws StudentNotException 
 74     {
 75         try {
 76             Document document=xmlutils.getDocument();
 77             NodeList list=document.getElementsByTagName("name");
 78             for(int i=0;i<=list.getLength();i++)
 79             {
 80                 if(list.item(i).getTextContent().equals(name))
 81                 {
 82                     list.item(i).getParentNode().getParentNode().removeChild(list.item(i).getParentNode());
 83                     xmlutils.writetoxml(document);
 84                     return;
 85                 }
 86             }
 87                     
 88                 throw new StudentNotException(name+"不存在！！！");
 89                 
 90                 
 91             }catch(StudentNotException e){
 92                 throw e;
 93             }
 94             
 95             
 96          catch (Exception e) {
 97             throw new RuntimeException(e);
 98          }
 99         
100     }
101     
102  
103 
104 }
 1 package test_system.UI;
 2 //和用户打交道的界面
 3 import java.io.BufferedReader;
 4 import java.io.IOException;
 5 import java.io.InputStreamReader;
 6 
 7 import test_system.student;
 8 import test_system.deo.studentdeo;
 9 import test_system.exception.StudentNotException;
10 
11 public class main {
12 
13     public static void main(String[] args) {
14         
15         try {
16             
17             System.out.println("添加学生(a)  删除学生(b)  查找学生(c)");
18             System.out.print("请输入操作类型:");
19             BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
20             String type=br.readLine();
21             if("a".equals(type))
22             {
23                 System.out.print("请输入学生姓名：");
24                 String name=br.readLine();
25                 System.out.print("请输入学生准考证号：");
26                 String examid=br.readLine();
27                 System.out.print("请输入学生身份证号：");
28                 String idcard=br.readLine();
29                 System.out.print("请输入学生所在地：");
30                 String location=br.readLine();
31                 System.out.print("请输入学生成绩：");
32                 String grade=br.readLine();
33                 student s=new student();
34                 s.setExamid(examid);
35                 s.setGrade(Double.parseDouble(grade));
36                 s.setIdcard(idcard);
37                 s.setLocation(location);
38                 s.setName(name);
39                 studentdeo deo=new studentdeo();
40                 deo.add(s);
41                 System.out.println("添加成功！！！");
42             }
43             else if("b".equals(type))
44             {
45                 System.out.println("请输入要删除学生的姓名");
46                     String name=br.readLine();
47                 try {
48                     
49                     studentdeo deo=new studentdeo();
50                     deo.delect(name);
51                     System.out.println("删除成功！");
52                 } catch (StudentNotException e) {
53                     System.out.println("你要删除的用户不存在！");
54                 }
55                 
56                 
57             }
58             else if("c".equals(type))
59             {
60                 System.out.println("请输入要查找学生的考号："); 
61                 String examid=br.readLine();
62                 
63                 
64                     studentdeo deo=new studentdeo();
65                     student a=deo.find(examid);
66                     System.out.print(a.getGrade());//这个地方该如何打印出学生的成绩
67                 
68                 
69             
70             }
71             else
72             {
73                 System.out.print("请输入正确的指令");
74             }
75         } catch (IOException e) {
76             
77             e.printStackTrace();
78             System.out.print("运行出错！！");
79         }
80     }
81 
82 }
package test_system.utils;

import java.io.FileOutputStream;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;

public class xmlutils {

    private static String filename="src/exam.xml";
    public static Document getDocument() throws Exception
    {
        DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
        DocumentBuilder builder=factory.newDocumentBuilder();
        
        return builder.parse(filename);
    }
    //封装把修稿的内容更新到xml文档中的方法
    public static void writetoxml(Document document) throws Exception
    {
        TransformerFactory factory=TransformerFactory.newInstance();
        Transformer tf=factory.newTransformer();
        tf.transform(new DOMSource(document), new StreamResult(new FileOutputStream(filename)));
    
    }
}
 1 package test_system.exception;
 2 
 3 //自定义的一个表示学生不存在的异常类
 4 public class StudentNotException extends Exception {
 5 
 6     public StudentNotException() {
 7         // TODO Auto-generated constructor stub
 8     }
 9 
10     public StudentNotException(String message) {
11         super(message);
12         // TODO Auto-generated constructor stub
13     }
14 
15     public StudentNotException(Throwable cause) {
16         super(cause);
17         // TODO Auto-generated constructor stub
18     }
19 
20     public StudentNotException(String message, Throwable cause) {
21         super(message, cause);
22         // TODO Auto-generated constructor stub
23     }
24 
25     public StudentNotException(String message, Throwable cause,
26             boolean enableSuppression, boolean writableStackTrace) {
27         super(message, cause, enableSuppression, writableStackTrace);
28         // TODO Auto-generated constructor stub
29     }
30 
31 }
 1 package test_system.test;
 2 
 3 import org.junit.Test;
 4 
 5 import test_system.student;
 6 import test_system.deo.studentdeo;
 7 import test_system.exception.StudentNotException;
 8 
 9 //测试add方法、delect方法和find方法的测试类
10 
11 public class student_test {
12 
13     @Test
14     public void studenttest() {
15         student a=new student();
16         studentdeo deo=new studentdeo();
17         a.setExamid("1212");
18         a.setGrade(98);
19         a.setIdcard("2324355");
20         a.setLocation("山东");
21         a.setName("山玩意");
22         deo.add(a);
23         
24     }
25     @Test
26     public void studenttest1() {
27 
28         studentdeo deo=new studentdeo();
29         deo.find("1212");
30     
31         
32     }
33     @Test
34     public void studenttest2() throws StudentNotException {
35 
36         studentdeo deo=new studentdeo();
37         deo.delect("aa");
38     
39         
40     }
41     
42     
43         
44     
45 
46 }
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原文地址：https://www.cnblogs.com/jjlovemm/p/4264694.html