JAVA操作XML实例分析

本文实例讲述了java操作xml的方法。分享给大家供大家参考。具体如下：

java代码如下：

import java.io.file;
import java.io.filenotfoundexception;
import java.io.fileoutputstream;
import java.io.ioexception;
import org.w3c.dom.*;
import org.xml.sax.saxexception;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.domsource;
import javax.xml.transform.stream.*;
import javax.xml.xpath.*;
public class test {
    public static void main(string[] args) {
        documentbuilderfactory factory=documentbuilderfactory.newinstance();
        element thebook=null, theelem=null, root=null;
        try {
            factory.setignoringelementcontentwhitespace(true);
            documentbuilder db=factory.newdocumentbuilder();
            document xmldoc=db.parse(new file("test1.xml"));
            root=xmldoc.getdocumentelement();
            thebook=(element) selectsinglenode("/books/book[name='哈里波特']", root);
            system.out.println("--- 查询找《哈里波特》 ----");
            element namenode=(element)thebook.getelementsbytagname("price").item(0);
            string name=namenode.getfirstchild().getnodevalue();
            system.out.println(name);
            output(thebook);
            system.out.println("=============selectsinglenode(books/book[name='哈里波特'], root)==================");
            //--- 新建一本书开始 ----
            thebook=xmldoc.createelement("book");
            theelem=xmldoc.createelement("name");
            theelem.settextcontent("新书");
            thebook.appendchild(theelem);
            theelem=xmldoc.createelement("price");
            theelem.settextcontent("20");
            thebook.appendchild(theelem);
            theelem=xmldoc.createelement("memo");
            theelem.settextcontent("新书的更好看。");
            thebook.appendchild(theelem);
            root.appendchild(thebook);
            system.out.println("--- 新建一本书开始 ----");
            output(xmldoc);
            system.out.println("==============================");
            //--- 新建一本书完成 ----
            //--- 下面对《哈里波特》做一些修改。 ----
            //--- 查询找《哈里波特》----
            //--- 此时修改这本书的价格 -----
            thebook.getelementsbytagname("price").item(0).settextcontent("15");//getelementsbytagname返回的是nodelist，所以要跟上item(0)。另外，getelementsbytagname("price")相当于xpath的".//price"。
            system.out.println("--- 此时修改这本书的价格 ----");
            output(thebook);
            //--- 另外还想加一个属性id，值为b01 ----
            thebook.setattribute("id", "b01");
            system.out.println("--- 另外还想加一个属性id，值为b01 ----");
            output(thebook);
            //--- 对《哈里波特》修改完成。 ----
            //--- 要用id属性删除《三国演义》这本书 ----
            thebook=(element) selectsinglenode("/books/book[@id='b02']", root);
            system.out.println("--- 要用id属性删除《三国演义》这本书 ----");
            output(thebook);
            thebook.getparentnode().removechild(thebook);
            system.out.println("--- 删除后的ｘｍｌ ----");
            output(xmldoc);
            //--- 再将所有价格低于10的书删除 ----
            nodelist somebooks=selectnodes("/books/book[price<10]", root);
            system.out.println("--- 再将所有价格低于10的书删除 ---");
            system.out.println("--- 符合条件的书有　"+somebooks.getlength()+"本。 ---");
            for(int i=0;i<somebooks.getlength();i++) {
                somebooks.item(i).getparentnode().removechild(somebooks.item(i));
            }
            output(xmldoc);
            savexml("test1_edited.xml", xmldoc);
        } catch (parserconfigurationexception e) {
            e.printstacktrace();
        } catch (saxexception e) {
            e.printstacktrace();
        } catch (ioexception e) {
            e.printstacktrace();
        }
    }
    public static void output(node node) {//将node的xml字符串输出到控制台
        transformerfactory transfactory=transformerfactory.newinstance();
        try {
            transformer transformer = transfactory.newtransformer();
            transformer.setoutputproperty("encoding", "gb2312");
            transformer.setoutputproperty("indent", "yes");
            domsource source=new domsource();
            source.setnode(node);
            streamresult result=new streamresult();
            result.setoutputstream(system.out);
            transformer.transform(source, result);
        } catch (transformerconfigurationexception e) {
            e.printstacktrace();
        } catch (transformerexception e) {
            e.printstacktrace();
        }  
    }
    public static node selectsinglenode(string express, object source) {//查找节点，并返回第一个符合条件节点
        node result=null;
        xpathfactory xpathfactory=xpathfactory.newinstance();
        xpath xpath=xpathfactory.newxpath();
        try {
            result=(node) xpath.evaluate(express, source, xpathconstants.node);
        } catch (xpathexpressionexception e) {
            e.printstacktrace();
        }
        return result;
    }
    public static nodelist selectnodes(string express, object source) {//查找节点，返回符合条件的节点集。
        nodelist result=null;
        xpathfactory xpathfactory=xpathfactory.newinstance();
        xpath xpath=xpathfactory.newxpath();
        try {
            result=(nodelist) xpath.evaluate(express, source, xpathconstants.nodeset);
        } catch (xpathexpressionexception e) {
            e.printstacktrace();
        }
        return result;
    }
    public static void savexml(string filename, document doc) {//将document输出到文件
        transformerfactory transfactory=transformerfactory.newinstance();
        try {
            transformer transformer = transfactory.newtransformer();
            transformer.setoutputproperty("indent", "yes");
            domsource source=new domsource();
            source.setnode(doc);
            streamresult result=new streamresult();
            result.setoutputstream(new fileoutputstream(filename));
            transformer.transform(source, result);
        } catch (transformerconfigurationexception e) {
            e.printstacktrace();
        } catch (transformerexception e) {
            e.printstacktrace();
        } catch (filenotfoundexception e) {
            e.printstacktrace();
        }  
    }
}

 
xml文件如下：

<?xml version="1.0" encoding="gbk"?>
<books>
<book>
<name>哈里波特</name>
<price>10</price>
<memo>这是一本很好看的书。</memo>
</book>
<book id="b02">
<name>三国演义</name>
<price>10</price>
<memo>四大名著之一。</memo>
</book>
<book id="b03">
<name>水浒</name>
<price>6</price>
<memo>四大名著之一。</memo>
</book>
<book id="b04">
<name>红楼</name>
<price>5</price>
<memo>四大名著之一。</memo>
</book>
</books>

希望本文所述对大家的java程序设计有所帮助。