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javaxml登陆代码 java登录完整代码

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初学JAVA 怎么用XML建立一个学生信息管理系统啊 管理员可以注册和登录 有增删改查功能 不需要图形化界面用DOM4J话基本上是对XML信息读取 以及对XML写 。
DOM4J写的话先在内存中生成一个DOM树 然后再用流写入XML中
读的话先从XML中读取 然后 逐个建对象赋值生成对象集合（List集合） 。然后对其集合判断（用来登陆）javaxml登陆代码，修改集合的对象（用来修改学生信息） 。删除javaxml登陆代码，改等等操作再简单不过了 。
javaxml登陆代码我这里有对XML读取 写入的代码 其javaxml登陆代码他的自己完成吧
import java.io.IOException;
import java.io.StringWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
import com.cssl.entity.Users;
/**
* Document Object Model for Java
* @author Administrator
*
*/
public class Dom4jDemo {
/**
* DOM4j解析
* @return
* @throws Exception
*/
public static ListUsers readXml() throws Exception{
ListUsers list = new ArrayListUsers();
//dom4j解析器
SAXReader reader = new SAXReader();
//解析文档
Document doc = reader.read("usersinfo.xml");
Element root = doc.getRootElement();
IteratorElement it = root.elementIterator("user");
while(it.hasNext()){
Element elt = it.next();
Users u = new Users();
u.setId(Integer.parseInt(elt.attributeValue("id")));
IteratorElement ch = elt.elementIterator();
u.setUsername(ch.next().getTextTrim());
u.setPassword(ch.next().getTextTrim());
list.add(u);
}
return list;
}
/**
* DOM4j写
* @param list
* @throws Exception
*/
public static void writeXml(ListUsers list) throws Exception{
//构建文档树
Document doc = DocumentHelper.createDocument();
Element root = doc.addElement("users");
for(Users u : list){
Element user = root.addElement("user").addAttribute("id", u.getId() "");
user.addElement("username").addText(u.getUsername());
user.addElement("password").setText(u.getPassword());
}
Writer out = new StringWriter();
//使用xml输出流写出去
XMLWriter writer = new XMLWriter(out,OutputFormat.createPrettyPrint());
writer.write(doc);
System.out.println(out);
out.close();
}
/**
* @param args
* @throws Exception
*/
public static void main(String[] args) throws Exception {
ListUsers list = readXml();
for(Users u : list){
System.out.println(u.getId() "\t" u.getUsername() "1\t" u.getPassword());
}
writeXml(list);
}
}
下面我写这个xml文件
?xml version="1.0" encoding="UTF-8"?
users
user id="1"
username小何/username
password123 /password
/user
user id="2"
username小曹/username
password456/password
/user
user id="3"
username小龚/username
password789/password
/user
/users
求一段 读出\修改 xml文件的java代码javax.xml.parsers
javax.xml.transform
javax.xml.transform.dom.DOMSource
javax.xml.transform.stream.StreamResult
org.w3c.dom
测试javaxml登陆代码的时候写的一个完整的操作XML的类javaxml登陆代码 ， 检测的投票系统
package tools;
import java.io.*;
import java.util.*;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import tools.Vote;
public class XmlHandler {
private DocumentBuilderFactory dbf=null;
private DocumentBuilder db=null;
private Document doc=null;
private List listXml=null;
public Document loadXml(File file)
{
try
{
dbf=DocumentBuilderFactory.newInstance();
db=dbf.newDocumentBuilder();
doc=db.parse(file);
}
catch(Exception e)
{
e.printStackTrace();
}
return doc;
}
public List getXmlData(File file)
{
if(doc==null){
doc=loadXml(file);
}
listXml=new ArrayList();
Element root=doc.getDocumentElement();//得到根节点votes
NodeList votes=root.getElementsByTagName("vote");//得到vote节点的集合
for(int i=0;ivotes.getLength();i)
{
Vote form=new Vote();
Element vote=(Element)votes.item(i);
form.setId(vote.getAttribute("id"));
form.setSum(vote.getAttribute("sum"));
form.setTitle(vote.getAttribute("title"));
form.setTime(vote.getAttribute("time"));
NodeList options=vote.getElementsByTagName("option");
String[] sums=new String[options.getLength()];//存储vote下每个option的sum
String[] opts=new String[options.getLength()];//存储vote下每个option的text
for(int k=0;koptions.getLength();k)
{
Element option=(Element)options.item(k);
sums[k]=option.getAttribute("sum");
opts[k]=option.getTextContent();
}
form.setSums(sums);
form.setOptions(opts);
listXml.add(form);
}
return listXml;
}
public void modifyXmlData(File file,int parentPos,int childPos)
{
if(doc==null){
doc=loadXml(file);
}
try{
Element root=doc.getDocumentElement();
NodeList votes=root.getElementsByTagName("vote");
Element vote=(Element)votes.item(parentPos);
int sum=Integer.parseInt(vote.getAttribute("sum")) 1;
//System.out.println(sum);
//vote.removeAttribute("sum");
vote.setAttribute("sum", String.valueOf(sum));
NodeList options=vote.getElementsByTagName("option");
//System.out.println(options.getLength());
Element option=(Element)options.item(childPos);
int opt_sum=Integer.parseInt(option.getAttribute("sum")) 1;
//option.removeAttribute("sum");
option.setAttribute("sum", String.valueOf(opt_sum));
}
catch(Exception e)
{
e.printStackTrace();
}
try//保存到XML文件
{
TransformerFactory tf=TransformerFactory.newInstance();
Transformer t=tf.newTransformer();
Properties props=t.getOutputProperties();
props.setProperty(OutputKeys.ENCODING, "gb2312");
t.setOutputProperties(props);
DOMSource dom=new DOMSource(doc);
StreamResult sr=new StreamResult(file);
t.transform(dom, sr);
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
public void deleteXmlData(File file,int parentPos,int childPos)//注javaxml登陆代码：该方法不支持批量删除javaxml登陆代码，批量删除可用split分割位置
{
if(doc==null)
{
doc=loadXml(file);
}
try
{
boolean flag;
if(childPos==-1)
{
flag=true;//删除父节点
}else{
flag=false;//删除子节点
}
Element root=doc.getDocumentElement();
Element vote=(Element)root.getElementsByTagName("vote").item(parentPos);
if(flag)//对父节点vote进行删除
{
root.removeChild(vote);
}else if(!flag)
{
Element option=(Element)vote.getElementsByTagName("option").item(childPos);
vote.setAttribute("sum", String.valueOf(Integer.parseInt(vote.getAttribute("sum"))-Integer.parseInt(option.getAttribute("sum"))));
vote.removeChild(option);
}
}
catch(Exception e)
{
e.printStackTrace();
}
try
{
TransformerFactory tf=TransformerFactory.newInstance();
Transformer t=tf.newTransformer();
Properties props=t.getOutputProperties();
props.setProperty(OutputKeys.ENCODING, "gb2312");
t.setOutputProperties(props);
DOMSource ds=new DOMSource(doc);
StreamResult sr=new StreamResult(file);
t.transform(ds, sr);
}
catch(Exception e)
{
e.printStackTrace();
}
}
public void appendXmlData(File file,String title,String[] options)
{
if(doc==null)
{
doc=loadXml(file);
}
try
{
Element root=doc.getDocumentElement();
Element vote=doc.createElement("vote");
root.appendChild(vote);
vote.setAttribute("time", new Date().toLocaleString());
vote.setAttribute("id", String.valueOf(root.getElementsByTagName("vote").getLength()));
vote.setAttribute("sum", "0");
vote.setAttribute("title", title);
for(int i=0;ioptions.length;i)
{
Element option=doc.createElement("option");
vote.appendChild(option);
option.setAttribute("sum", "0");
option.setTextContent(options[i]);
}
}
catch(Exception ex){
ex.printStackTrace();
}
try{
TransformerFactory tf=TransformerFactory.newInstance();
Transformer t=tf.newTransformer();
Properties props=t.getOutputProperties();
props.setProperty(OutputKeys.ENCODING, "gb2312");
t.setOutputProperties(props);
DOMSource dom=new DOMSource(doc);
StreamResult sr=new StreamResult(file);
t.transform(dom, sr);
}catch(Exception ex){
ex.printStackTrace();
}
}
public Vote selectSingleOne(File file,int parentPos)
{
if(doc==null)
{
doc=loadXml(file);
}
Element root=doc.getDocumentElement();
Element vote=(Element)root.getElementsByTagName("vote").item(parentPos);
Vote form=new Vote();
form.setId(vote.getAttribute("id"));
form.setTime(vote.getAttribute("time"));
form.setTitle(vote.getAttribute("title"));
form.setSum(vote.getAttribute("sum"));
int len=vote.getElementsByTagName("option").getLength();
NodeList nodeList=vote.getElementsByTagName("option");
String[] sums=new String[len];
String[] opts=new String[len];
for(int i=0;ilen;i)
{
Element option=(Element)nodeList.item(i);
sums[i]=option.getAttribute("sum");
opts[i]=option.getTextContent();
}
form.setOptions(opts);
form.setSums(sums);
return form;
}
public void modifyOneXmlData(File file,int parentPos,String title,String[] options)
{
if(doc==null){
doc=loadXml(file);
}
try
{
Element root=doc.getDocumentElement();
Element vote=(Element)root.getElementsByTagName("vote").item(parentPos);
vote.setAttribute("title", title);
vote.setAttribute("sum", "0");
int len=vote.getElementsByTagName("option").getLength();
for(int i=0;ilen;i)
{
Element option=(Element)vote.getElementsByTagName("option").item(i);
option.setAttribute("sum", "0");
option.setTextContent(options[i]);
}
}catch(Exception ex){
ex.printStackTrace();
}
try
{
TransformerFactory tf=TransformerFactory.newInstance();
Transformer t=tf.newTransformer();
Properties props=t.getOutputProperties();
props.setProperty(OutputKeys.ENCODING, "gb2312");
t.setOutputProperties(props);
DOMSource dom=new DOMSource(doc);
StreamResult sr=new StreamResult(file);
t.transform(dom, sr);
}catch(Exception ex){
ex.printStackTrace();
}
}
public void addOptionXmlData(File file,int parentPos,String option)
{
if(doc==null){
doc=loadXml(file);
}
try
{
Element root=doc.getDocumentElement();
Element voot=(Element)root.getElementsByTagName("vote").item(parentPos);
Element optionNode=doc.createElement("option");
voot.appendChild(optionNode);
optionNode.setTextContent(option);
optionNode.setAttribute("sum", "0");
}catch(Exception ex){
ex.printStackTrace();
}
try
{
TransformerFactory tf=TransformerFactory.newInstance();
Transformer t=tf.newTransformer();
Properties props=t.getOutputProperties();
props.setProperty(OutputKeys.ENCODING, "gb2312");
t.setOutputProperties(props);
DOMSource dom=new DOMSource(doc);
StreamResult sr=new StreamResult(file);
t.transform(dom, sr);
}catch(Exception ex)
{
ex.printStackTrace();
}
}
}
200分求帮写个JAVA读取XML的代码解析xml方法 ， 供参考，希望能帮助lz点
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package xml;
import java.io.*;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.w3c.dom.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.StreamResult;
import org.xml.sax.SAXException;
public class MyXMLReader {
public String libPath = null;
public String filePath;
public void setFilePath(String filePath) {
this.filePath = filePath;
}
public String getLibPath() {
return libPath;
}
//得到用户xml中各个节点的值
public void getPathValue(String xmlPath) throws ParserConfigurationException, SAXException, IOException {
File f = new File(xmlPath);
FileInputStream fs=new FileInputStream(f);
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(f);
NodeList n2 = doc.getDocumentElement().getElementsByTagName("context-param");
for (int i = 0; in2.getLength(); i) {
String name = doc.getElementsByTagName("param-name").item(i).getFirstChild().getNodeValue();
String value = https://www.04ip.com/post/doc.getElementsByTagName("param-value").item(i).getFirstChild().getNodeValue();
if (name.equals("libPath")) {
libPath = value;
}
}
}
//将要更新文件中的值替换掉
public void setPathValue() throws ParserConfigurationException, SAXException, IOException {
String xml="./hzims/Tomcat6/webapps/ROOT/WEB-INF/web.xml";
File f = new File(xml);
FileInputStream fs=new FileInputStream(f);
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(f);
NodeList n2 = doc.getDocumentElement().getElementsByTagName("context-param");
for (int i = 0; in2.getLength(); i) {
String name = doc.getElementsByTagName("param-name").item(i).getFirstChild().getNodeValue();
String value = https://www.04ip.com/post/doc.getElementsByTagName("param-value").item(i).getFirstChild().getNodeValue();
if (name.equals("libPath")) {
doc.getElementsByTagName("param-value").item(i).getFirstChild().setNodeValue(libPath);
try {
reSetValue(doc,"./hzims/Tomcat6/webapps/ROOT/WEB-INF/web.xml" );
} catch (FileNotFoundException ex) {
Logger.getLogger(MyXMLReader.class.getName()).log(Level.SEVERE, null, ex);
} catch (TransformerConfigurationException ex) {
Logger.getLogger(MyXMLReader.class.getName()).log(Level.SEVERE, null, ex);
} catch (TransformerException ex) {
Logger.getLogger(MyXMLReader.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
public void reSetValue(Document doc, String path) throws FileNotFoundException, IOException, TransformerConfigurationException,
TransformerException {
TransformerFactory tFactory = TransformerFactory.newInstance();
Transformer transformer = tFactory.newTransformer();
//设置输出的encoding为改变gb2312
transformer.setOutputProperty("encoding", "gb2312");
DOMSource source = new DOMSource(doc);
StreamResult result = new StreamResult(new File(path));
transformer.transform(source, result);
}
}
用java怎样编写登录页面,成功登录跳转到下一个页面,求代码说说servlet里面的方法：
public void ValidateUserPass(String user,String pass){
RequestDispathcher rd =null
//假使你的代码是从DB中获取
DBFactory db=DBFactoryImpl.getDBFactoryInstance();//得到数据库链接
flg=db.findUser(user,pass);
// 这里是不存在用户
if(flg.hasNext()==-1){
// 登录时错误了 ， 一般我们会给用户一个提示
session.setAttirbute("msg","对不起，用户名或密码错误");
RequestDispathcher rd = req.getRequesDispatcher("login.jsp")；
rd.forward(request, reponse);//将请求对象和响应对象传递进来
}// 这里是存在当前用户
else{
//当然这里登录成功时，我们要把当前用户写到session里面保存
session.setAttirbute("userName",user);
//这个请求转发语句
request.sendRedirect("index.html");
}
}
// * 上述代码，你可以参考下我的方法，我也很久没做JAVA开发了，我现在从事前端UI开发 ， 本来我想在写一个用struts 2登录的程序的 ， 可我现在忘得差不多了，上面我所用到的属性建议你自己好好的研究一下，往后你将学到struts2 hibernate，Spring等一系列优秀的开源框架，说白了，这些东西的底层还是这些，只不过这些框架做了一些封装隔离 。上述代码建议你重点理解一下：请求转发和重定向的区别 。
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