JavaWeb学习笔记-XML-4

jaxp

public class StudentDao {
public void add(Student s){
try {
Document document = XmlUtils.getDocument();
Element studnet_tag = document.createElement("student");
studnet_tag.setAttribute("idcard",s.getIdcard());
studnet_tag.setAttribute("examid",s.getExamid());
Element name = document.createElement("name");
Element locatoion = document.createElement("location");
Element grade = document.createElement("grade");
name.setTextContent(s.getName());
locatoion.setTextContent(s.getLocation());
grade.setTextContent(s.getGrade()+"");
studnet_tag.appendChild(name);
studnet_tag.appendChild(locatoion);
studnet_tag.appendChild(grade);
document.getElementsByTagName("exam").item(0).appendChild(studnet_tag);
XmlUtils.write2Xml(document);
} catch (Exception e) {
throw new RuntimeException(e);
}

}
public Student find(String examid){
try {
Document document = XmlUtils.getDocument();
NodeList list = document.getElementsByTagName("student");
for(int i=0; i<list.getLength();i++){
Element student_tag = (Element) list.item(i);
if(student_tag.getAttribute("examid").equals(examid)){
Student s = new Student();
s.setExamid(examid);
s.setIdcard(student_tag.getAttribute("idcard"));
s.setName(student_tag.getElementsByTagName("name").item(0).getTextContent());
s.setLocation(student_tag.getElementsByTagName("location").item(0).getTextContent());
s.setGrade(Double.parseDouble(student_tag.getElementsByTagName("grade").item(0).getTextContent()));
return s;
}
}
} catch (Exception e) {
throw new RuntimeException(e);
}
return null;
}
public void delete(String name) throws StudentNotExistException {

try {
Document document = XmlUtils.getDocument();

NodeList list = document.getElementsByTagName("name");
for(int i=0; i<list.getLength(); i++){
if(list.item(i).getTextContent().equals(name)){
list.item(i).getParentNode().getParentNode().removeChild(list.item(i).getParentNode());
XmlUtils.write2Xml(document);
}
}
throw new StudentNotExistException(name+"不存在");
} catch (StudentNotExistException e){
throw e;
}catch (Exception e) {
throw new RuntimeException(e);
}

}

}

public class Student
{
private String idcard;
private String examid;
private String name;
private String location;
private double grade;

public String getIdcard(){
return this.idcard;
}

public double getGrade() {
return grade;
}

public String getExamid() {
return examid;
}

public String getLocation() {
return location;
}

public String getName() {
return name;
}

public void setExamid(String examid) {
this.examid = examid;
}

public void setGrade(double grade) {
this.grade = grade;
}

public void setIdcard(String idcard) {
this.idcard = idcard;
}

public void setLocation(String location) {
this.location = location;
}

public void setName(String name) {
this.name = name;
}

}

public class StudentNotExistException extends Exception {

public StudentNotExistException() {
super();
}

public StudentNotExistException(String s) {
super(s);
}

public StudentNotExistException(String message, Throwable cause) {
super(message, cause);
}

public StudentNotExistException(Throwable cause) {
super(cause);
}

protected StudentNotExistException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
super(message, cause, enableSuppression, writableStackTrace);
}
}

public class Main {
public static void main(String[] args){
System.out.println("添加学生（a） 删除学生（b） 查找学生（c）");
System.out.println("请输入操作类型:");
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
try {
String type = br.readLine();
if("a".equals(type)){
System.out.println("请输入学生姓名:");
String name = br.readLine();
System.out.println("请输入学生准考证号:");
String examid = br.readLine();
System.out.println("请输入学生身份证号:");
String idcard = br.readLine();
System.out.println("请输入学生所在地:");
String location = br.readLine();
System.out.println("请输入学生成绩:");
String grade = br.readLine();
Student s = new Student();
s.setIdcard(idcard);
s.setName(name);
s.setLocation(location);
s.setGrade(Double.parseDouble(grade));
s.setExamid(examid);
StudentDao dao = new StudentDao();
dao.add(s);

}else if("b".equals(type)){
System.out.println("请输入学生姓名");
String name = br.readLine();
StudentDao dao = new StudentDao();
try {
dao.delete(name);
System.out.println("删除成功");
} catch (StudentNotExistException e) {
System.out.println("学生不存在");
}

}else if("c".equals(type)){

}else{
System.out.println("不支持此操作");
}

} catch (IOException e) {
e.printStackTrace();
System.out.println("对不起，系统出错");
}

}
}

public class XmlUtils {
private static String fileNmae = "src/exam.xml";
public static Document getDocument() throws IOException, SAXException, ParserConfigurationException {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
return builder.parse(fileNmae);
}
public static void write2Xml(Document documnet) throws TransformerException, FileNotFoundException {
TransformerFactory factory = TransformerFactory.newInstance();
Transformer tf = factory.newTransformer();
tf.transform(new DOMSource(documnet),new StreamResult(new FileOutputStream(fileNmae)));
}
}

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<exam>
<student examid="222" idcade="111">
<name>张三</name>
<location>沈阳</location>
<garde>89</garde>
</student>
<student examid="444" idcade="333">
<name>李四</name>
<location>大连</location>
<garde>97</garde>
</student>
<student examid="121" idcard="">
<name>aa</name>
<location>北京</location>
<grade>89.0</grade>
</student>
</exam>