-->
<web-app>
<servlet>
<servlet-name>snoop</servlet-name>
<servlet-class>SnoopServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>file </servlet-name>
<servlet-class>ViewFile</servlet-class>
<init-param>
<param-name>initial</param-name>
<param-value>1000</param-value>
<description>The initial value for the counter <!-- optional --></description>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>mv</servlet-name>
<url-pattern>*.wm</url-pattern>
</servlet-mapping>
<distributed/>
<security-role>
<role-name>manager</role-name>
<role-name>director</role-name>
<role-name>president</role-name>
</security-role>
</web-app>
處理程序：
import java.io.*;
import java.util.*;
public class XPathReader {
public static void main(String[] args) throws IOException, JDOMException {
if (args.length != 1) {
System.err.println("Usage: java XPathReader web.xml");
return;
}
String filename = args[0];//從命令行輸入web.xml
PrintStream out = System.out;
SAXBuilder builder = new SAXBuilder();
Document doc = builder.build(new File(filename));//得到Document對象
// Print servlet information
XPath servletPath = XPath.newInstance("http://servlet");//,選擇任意路徑下servlet元素
List servlets = servletPath.selectNodes(doc);//返回所有的servlet元素。
out.println("This WAR has "+ servlets.size() +" registered servlets:");
Iterator i = servlets.iterator();
while (i.hasNext()) {//輸出servlet信息
Element servlet = (Element) i.next();
out.print("\t" + servlet.getChild("servlet-name")
.getTextTrim() +
" for " + servlet.getChild("servlet-class")
.getTextTrim());
List initParams = servlet.getChildren("init-param");
out.println(" (it has " + initParams.size() + " init params)");
}
// Print security role information
XPath rolePath = XPath.newInstance("http://security-role/role-name/text()");
List roleNames = rolePath.selectNodes(doc);//得到所有的角色名
if (roleNames.size() == 0) {
out.println("This WAR contains no roles");
} else {
out.println("This WAR contains " + roleNames.size() + " roles:");
i = roleNames.iterator();
while (i.hasNext()) {//輸出角色名
out.println("\t" + ((Text)i.next()).getTextTrim());
}
}
}
}
輸出結(jié)果:
C:\java>java XPathReader web.xml
This WAR has 2 registered servlets:
snoop for SnoopServlet (it has 0 init params)
file for ViewFile (it has 1 init params)
This WAR contains 3 roles:
manager
director
president
6、數(shù)據(jù)輸入要用到XML文檔要通過org.jdom.input包，反過來需要org.jdom.output。如前面所說，關(guān)是看API文檔就能夠使用。
我們的例子讀入XML文件exampleA.xml，加入一條處理指令，修改第一本書的價格和作者，并添加一條屬性，然后寫入文件exampleB.xml：
//exampleA.xml
<?xml version="1.0" encoding="GBK"?>
<bookList>
<book>
<name>Java編程入門</name>
<author>張三</author>
<publishDate>2002-6-6</publishDate>
<price>35.0</price>
</book>
<book>
<name>XML在Java中的應(yīng)用</name>
<author>李四</author>
<publishDate>2002-9-16</publishDate>
<price>92.0</price>
</book>
</bookList>
//testJDOM.java
import org.jdom.*;
import org.jdom.output.*;
import org.jdom.input.*;
import java.io.*;
public class TestJDOM{
public static void main(String args[])throws Exception{
SAXBuilder sb = new SAXBuilder();
//從文件構(gòu)造一個Document，因為XML文件中已經(jīng)指定了編碼，所以這里不必了
Document doc = sb.build(new FileInputStream("exampleA.xml"));
ProcessingInstruction pi = new ProcessingInstruction//加入一條處理指令
("xml-stylesheet","href=\"bookList.html.xsl\" type=\"text/xsl\"");
doc.addContent(pi);
Element root = doc.getRootElement(); //得到根元素
java.util.List books = root.getChildren(); //得到根元素所有子元素的集合
Element book = (Element)books.get(0); //得到第一個book元素
//為第一本書添加一條屬性
Attribute a = new Attribute("hot","true");
book.setAttribute(a);
Element author = book.getChild("author"); //得到指定的字元素
author.setText("王五"); //將作者改為王五
//或 Text t = new Text("王五");book.addContent(t);
Element price = book.getChild("price"); //得到指定的字元素
//修改價格，比較郁悶的是我們必須自己轉(zhuǎn)換數(shù)據(jù)類型，而這正是JAXB的優(yōu)勢
author.setText(Float.toString(50.0f));
String indent = " ";
boolean newLines = true;
XMLOutputter outp = new XMLOutputter(indent,newLines,"GBK");
outp.output(doc, new FileOutputStream("exampleB.xml"));
}
};
執(zhí)行結(jié)果exampleB.xml：
<?xml version="1.0" encoding="GBK"?>
<bookList>
<book hot=”true”>
<name>Java編程入門</name>
<author>50.0</author>
<publishDate>2002-6-6</publishDate>
<price>35.0</price>
</book>
<book>
<name>XML在Java中的應(yīng)用</name>
<author>李四</author>
<publishDate>2002-9-16</publishDate>
<price>92.0</price>
</book>
</bookList>
<?xml-stylesheet href="bookList.html.xsl" type="text/xsl"?>
在默認(rèn)情況下，JDOM的Element類的getText()這類的方法不會過濾空白字符，如果你需要過濾，用setTextTrim() 。
posted on 2005-09-03 10:26
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