xml文档-exam.xml
<?xml version="1.0" encoding="UTF-8"?>
<exam>
<student examid="111" idcard="111123123">
<name>张三</name>
<location>沈阳</location>
<grade>89</grade>
</student>
<student examid="222" idcard="22212342323">
<name>李四</name>
<location>大连</location>
<grade>97</grade>
</student>
</exam>
程序实现：完成对exam.xml文档的添加、删除、查询功能
工具类-XmlUtils
import java.io.File;
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.xml.sax.SAXException;
public class XmlUtils {
private static File file = new File("src/exam.xml");
public static Document getDocument() throws ParserConfigurationException, SAXException, IOException{
//1.获得工厂的实例对象
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
//2.获得DocumentBuilder的实例对象
DocumentBuilder builder = factory.newDocumentBuilder();
return builder.parse(file);
}
public static void write2Xml(Document document) throws TransformerException{
//1.获得TransformerFactory的实例对象
TransformerFactory factory = TransformerFactory.newInstance();
//2.获得Transformer的实例对象
Transformer tf = factory.newTransformer();
tf.transform(new DOMSource(document), new StreamResult(file));
}
}
封装数据的Student类
public class Student {
private String examid;
private String idcard;
private String name;
private String location;
private double grade;
public String getExamid() {
return examid;
}
public void setExamid(String examid) {
this.examid = examid;
}
public String getIdcard() {
return idcard;
}
public void setIdcard(String idcard) {
this.idcard = idcard;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public double getGrade() {
return grade;
}
public void setGrade(double grade) {
this.grade = grade;
}
@Override
public String toString() {
return "学生姓名:"+name+", 学生住址:"+location+", 准考证号:"+examid+", 身份证号:"+idcard+", 成绩:"+grade;
}
}
俗称javabean的StudentDao类
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class StudentDao {
private static XmlUtils utils = new XmlUtils();
public static void add(Student student){
try {
Document document = utils.getDocument(); //获得要操作的xml文档的document对象
//创建各节点
Element student_node = document.createElement("student");
Element name_node = document.createElement("name");
Element location_node = document.createElement("location");
Element grade_node = document.createElement("grade");
//给各节点添加属性和值
student_node.setAttribute("examid", student.getExamid());
student_node.setAttribute("idcard", student.getIdcard());
name_node.setTextContent(student.getName());
location_node.setTextContent(student.getLocation());
grade_node.setTextContent(student.getGrade()+""); //
//将各节点添加到相应位置
student_node.appendChild(name_node);
student_node.appendChild(location_node);
student_node.appendChild(grade_node);
//student_node.getParentNode().appendChild(student_node);
document.getElementsByTagName("exam").item(0).appendChild(student_node);
//将内存中的document对象重新写入xml文档
utils.write2Xml(document);
//System.out.println("添加学生信息成功");
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public static boolean delete(String name){
try {
Document document = utils.getDocument(); //获得要操作的xml文档的document对象
NodeList list = document.getElementsByTagName("name");
for(int i=0; list!=null && i<list.getLength(); i++){
Node node = list.item(i);
if(node.getTextContent().equals(name)){
node.getParentNode().getParentNode().removeChild(node.getParentNode());
utils.write2Xml(document);
return true;
}
}
return false;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public static Student find(String examid){
try {
Student s = new Student();
Document document = utils.getDocument();
NodeList list = document.getElementsByTagName("student");
for(int i=0; list!=null && i<list.getLength(); i++){
Element node = (Element) list.item(i);
if(node.getAttribute("examid").equals(examid)){
s.setExamid(examid);
s.setIdcard(node.getAttribute("idcard"));
s.setGrade(Double.parseDouble(node.getElementsByTagName("grade").item(0).getTextContent()));
s.setLocation(node.getElementsByTagName("location").item(0).getTextContent());
s.setName(node.getElementsByTagName("name").item(0).getTextContent());
return s;
}
}
} catch (Exception e) {
throw new RuntimeException(e);
}
return null;
}
}
封装主函数的Main类
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Main {
private static StudentDao dao = new StudentDao();
public static void main(String[] args) {
System.out.println("操作类型: 添加学生信息:(a) 删除学生信息:(b) 查询学生信息:(c)");
System.out.print("请选择操作类型： ");
Operation();
}
private static void Operation() {
try {
Student s = new Student();
//创建读取键盘的BufferedReader对象，并用转换流InputStreamReader将字节流System.in转换为字符流
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String type = br.readLine();
if("a".equals(type)){
System.out.print("请输入学生姓名:");
String name = br.readLine();
System.out.print("请输入学生准考证号:");
String examid = br.readLine();
System.out.print("请输入学生身份证号:");
String idcard = br.readLine();
System.out.print("请输入学生住址:");
String location = br.readLine();
System.out.print("请输入学生成绩:");
String grade = br.readLine();
s.setExamid(examid);
s.setGrade(Double.parseDouble(grade));
s.setIdcard(idcard);
s.setLocation(location);
s.setName(name);
dao.add(s);
System.out.println("添加学生信息成功！！！");
}else if("b".equals(type)){
System.out.print("请输入学生姓名: ");
String name = br.readLine();
boolean b = dao.delete(name);
if(b){
System.out.println("删除学生信息成功！！");
}else{
System.out.println("删除学生信息失败,请检查学生姓名是否输入正确！！");
}
}else if("c".equals(type)){
System.out.print("请输入学生准考证号: ");
String examid = br.readLine();
s = dao.find(examid);
if(s!=null){
System.out.println(s);
}else{
System.out.println("此学生信息不存在，请检查准考证号是否输入正确！！");
}
}else{
System.out.println("输入错误！！！！");
System.out.print("请重新选择操作类型: ");
Operation();
}
} catch (Exception e) {
e.printStackTrace();
System.out.println("程序出现未知错误，请致电:1384389438!!!!");
}
}
}