xml解析（超全）---（三）
DOM4J
/**
? * doc2XmlFile 将Document对象保存为一个xml文件到本地
? *
? * @return true:保存成功 flase:失败
? * @param filename
? *??????????? 保存的文件名
? * @param document
? *??????????? 需要保存的document对象
? */
?public static boolean doc2XmlFile(Document document, String filename) {
??boolean flag = true;
??try {
???/* 将document中的内容写入文件中 */
???// 默认为UTF-8格式，指定为"GB2312"
???OutputFormat format = OutputFormat.createPrettyPrint();
???format.setEncoding("GB2312");
???XMLWriter writer = new XMLWriter(
?????new FileWriter(new File(filename)), format);
???writer.write(document);
???writer.close();
??} catch (Exception ex) {
???flag = false;
???ex.printStackTrace();
??}
??return flag;
?}
/**
? * string2XmlFile 将xml格式的字符串保存为本地文件，如果字符串格式不符合xml规则，则返回失败
? *
? * @return true:保存成功 flase:失败
? * @param filename
? *??????????? 保存的文件名
? * @param str
? *??????????? 需要保存的字符串
? */
?public static boolean string2XmlFile(String str, String filename) {
??boolean flag = true;
??try {
???Document doc = DocumentHelper.parseText(str);
???flag = doc2XmlFile(doc, filename);
??} catch (Exception ex) {
???flag = false;
???ex.printStackTrace();
??}
??return flag;
?}
/**
? * load 载入一个xml文档
? *
? * @return 成功返回Document对象，失败返回null
? * @param uri
? *??????????? 文件路径
? */
?public static Document load(String filename) {
??Document document = null;
??try {
???SAXReader saxReader = new SAXReader();
???document = saxReader.read(new File(filename));
??} catch (Exception ex) {
???ex.printStackTrace();
??}
??return document;
?}
/**
? * xmlWriteDemoByString 演示String保存为xml文件
? */
?public void xmlWriteDemoByString() {
??String s = "";
??/** xml格式标题 "<?xml version='1.0' encoding='GB2312'?>" 可以不用写 */
??s = "<config>\r\n" + "??? <ftp name='DongDian'>\r\n"
????+ "????? <ftp-host>127.0.0.1</ftp-host>\r\n"
????+ "????? <ftp-port>21</ftp-port>\r\n"
????+ "????? <ftp-user>cxl</ftp-user>\r\n"
????+ "????? <ftp-pwd>longshine</ftp-pwd>\r\n"
????+ "????? <!-- ftp最多尝试连接次数 -->\r\n"
????+ "????? <ftp-try>50</ftp-try>\r\n"
????+ "????? <!-- ftp尝试连接延迟时间 -->\r\n"
????+ "????? <ftp-delay>10</ftp-delay>\r\n" + "?? </ftp>\r\n"
????+ "</config>\r\n";
??// 将文件生成到classes文件夹所在的目录里
??string2XmlFile(s, "d://xmlWriteDemoByString.xml");
??// 将文件生成到classes文件夹里
//??string2XmlFile(s, "classes/xmlWriteDemoByString.xml");
?}
/**
? * 演示手动创建一个Document，并保存为XML文件
? */
?public void xmlWriteDemoByDocument() {
??/** 建立document对象 */
??Document document = DocumentHelper.createDocument();
??/** 建立config根节点 */
??Element configElement = document.addElement("config");
??/** 建立ftp节点 */
??configElement.addComment("东电ftp配置");
??Element ftpElement = configElement.addElement("ftp");
??ftpElement.addAttribute("name", "DongDian");
??/** ftp 属性配置 */
??Element hostElement = ftpElement.addElement("ftp-host");
??hostElement.setText("127.0.0.1");
??(ftpElement.addElement("ftp-port")).setText("21");
??(ftpElement.addElement("ftp-user")).setText("cxl");
??(ftpElement.addElement("ftp-pwd")).setText("longshine");
??ftpElement.addComment("ftp最多尝试连接次数");
??(ftpElement.addElement("ftp-try")).setText("50");
??ftpElement.addComment("ftp尝试连接延迟时间");
??(ftpElement.addElement("ftp-delay")).setText("10");
??/** 保存Document */
??doc2XmlFile(document, "d://xmlWriteDemoByDocument.xml");
?}
/**
? * 演示读取文件的具体某个节点的值
? */
?public static void xmlReadDemo() {
??Document doc = load("d://xmlWriteDemoByDocument.xml");
??// Element root = doc.getRootElement();
??/** 先用xpath查找所有ftp节点 并输出它的name属性值 */
??List list = doc.selectNodes("/config/ftp");
??Iterator it = list.iterator();
??while (it.hasNext()) {
???Element ftpElement = (Element) it.next();
???System.out.println("ftp_name="
?????+ ftpElement.attribute("name").getValue());
??}
??/** 直接用属性path取得name值 */
??list = doc.selectNodes("/config/ftp/@name");
??it = list.iterator();
??while (it.hasNext()) {
???Attribute attribute = (Attribute) it.next();
???System.out.println("@name=" + attribute.getValue());
??}
??/** 直接取得DongDian ftp的 ftp-host 的值 */
??list = doc.selectNodes("/config/ftp/ftp-host");
??it = list.iterator();
??Element hostElement = (Element) it.next();
??System.out.println("DongDian's ftp_host=" + hostElement.getText());
?}
/**
? * doc2String 将xml文档内容转为String
? *
? * @return 字符串
? * @param document
? */
?public static String doc2String(Document document) {
??String s = "";
??try {
???// 使用输出流来进行转化
???ByteArrayOutputStream out = new ByteArrayOutputStream();
???// 使用GB2312编码
???OutputFormat format = new OutputFormat("?? ", true, "UTF-8");
???XMLWriter writer = new XMLWriter(out, format);
???writer.write(document);
???s = out.toString("UTF-8");
??} catch (Exception ex) {
???ex.printStackTrace();
??}
??return s;
?}
?实例一：（读取硬盘存在的xml文件）
?SAXReader read=new SAXReader();
???Document doc=null;
???try {
????doc=read.read(new File("d://student.xml"));
????
????List classes=doc.selectNodes("//class");
????System.out.println("某学校共有"+classes.size()+"个班级");
????
????for(Iterator it=classes.iterator();it.hasNext();){
?????Element eleClass=(Element)it.next();
?????String id=eleClass.attributeValue("name");
?????System.out.println("班级 "+id);
?????System.out.println("***********************");
?????Iterator it1=eleClass.elementIterator();
?????while(it1.hasNext()){
??????Element eleStu=(Element)it1.next();
??????String name=eleStu.elementText("name");
??????String age=eleStu.element("age").getTextTrim();
??????System.out.println("姓名："+name);
??????System.out.println("年龄："+age);
?????}
????}
????
???} catch (DocumentException e) {
????e.printStackTrace();
???}
?实例二：（读取xml字符串）
?StringBuffer sb=new StringBuffer("<?xml version="1.0" encoding="gb2312"?>");
???sb.append("<result>");
???sb.append("<class name="1">");
???sb.append("<student id="1">");
???sb.append("<name>龙准</name>");
???sb.append("<age>25</age>");
???sb.append("</student>");
???sb.append("<student id="2">");
???sb.append("<name>龙准2</name>");
???sb.append("<age>23</age>");
???sb.append("</student>");
???sb.append("</class>");
???sb.append("</result>");
???
???try {
????//第一种读取xml字符串的写法
????Document doc=DocumentHelper.parseText(sb.toString());
????//第二种读取xml字符串的写法
//????SAXReader read=new SAXReader();
//????Document doc=read.read(new StringReader(sb.toString()));
????//第三种读取xml字符串的写法
//????SAXReader read=new SAXReader();
//????Document doc=read.read(new ByteArrayInputStream(sb.toString().getBytes()));
????
????List list=doc.selectNodes("//class");
????System.out.println("某学校共有"+list.size()+"个班级");
????for(Iterator it=list.iterator();it.hasNext();){
?????Element eleClass=(Element)it.next();
?????String id=eleClass.attributeValue("name");
?????System.out.println("班级 "+id);
?????System.out.println("***********************");
?????for(Iterator it1=eleClass.elementIterator();it1.hasNext();){
??????Element eleStu=(Element)it1.next();
??????String name=eleStu.element("name").getText();
??????String age=eleStu.elementText("age");
??????System.out.println("姓名："+name);
??????System.out.println("年龄："+age);
?????}
????}
????
???} catch (DocumentException e) {
????e.printStackTrace();
???}
?实例三：（手动创建document并读取）
?Document doc=DocumentHelper.createDocument();
???Element eleResult=doc.addElement("result");
???Element eleClas=eleResult.addElement("class");
???eleClas.addAttribute("name", "1");
???Element elestu=eleClas.addElement("student");
???elestu.addAttribute("id", "1");
???Element eleName=elestu.addElement("name");
???eleName.addText("龙准");
???Element eleAge=elestu.addElement("age");
???eleAge.addText("25");
???
???Element elestu2=eleClas.addElement("student").addAttribute("id", "2");
???elestu2.addElement("name").setText("龙准");
???elestu2.addElement("age").setText("23");
???
???List list=doc.selectNodes("//class");
???System.out.println("某学校共有"+list.size()+"个班级");
???for(Iterator it=list.iterator();it.hasNext();){
????Element eleClass=(Element)it.next();
????String id=eleClass.attributeValue("name");
????System.out.println("班级 "+id);
????System.out.println("***********************");
????for(Iterator it1=eleClass.elementIterator();it1.hasNext();){
?????Element eleStu=(Element)it1.next();
?????String name=eleStu.element("name").getText();
?????String age=eleStu.elementText("age");
?????System.out.println("姓名："+name);
?????System.out.println("年龄："+age);
????}
???}
