Java对XML文件增删改查操作示例

三叶草

这篇文章主要介绍了Java对XML文件增删改查操作,结合完整实例形式分析了java针对xml格式数据的常见读写、增删改查等操作技巧,需要的朋友可以参考下
本文实例讲述了java对xml文件增删改查操作。分享给大家供大家参考，具体如下：
xml文件：

<?xml version="1.0" encoding="utf-8"?>
<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>

增删改查 test.java

import java.io.file;
import java.io.fileoutputstream;
import org.w3c.dom.*;
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 = (document) db.parse(new file("test.xml"));
    root = xmldoc.getdocumentelement();
    // --- 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);
    // --- 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》----
    thebook = (element) selectsinglenode("/books/book[name='哈里波特']",
      root);
    system.out.println("--- 查询找《哈里波特》 ----");
    output(thebook);
    // --- 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 (exception e) {
    e.printstacktrace();
  }
  }
  /**
   * 将node的xml字符串输出到控制台
   *
   * @param node
   */
  public static void output(node node) {
  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 (exception e) {
    e.printstacktrace();
  }
  }
  /**
   * 查找节点，并返回第一个符合条件节点
   *
   * @param express
   * @param source
   * @return
   */
  public static node selectsinglenode(string express, object source) {
  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;
  }
  /**
   * 查找节点，返回符合条件的节点集。
   * @param express
   * @param source
   * @return
   */
  public static nodelist selectnodes(string express, object source) {
  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;
  }
  /**
   * 将document输出到文件
   * @param filename
   * @param doc
   */
  public static void savexml(string filename, document doc) {
  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 (exception e) {
    e.printstacktrace();
  }
  }
}

ps：这里再为大家提供几款关于xml操作的在线工具供大家参考使用：
xml在线压缩/格式化工具：https://tool.zzvips.com/t/xml/
希望本文所述对大家java程序设计有所帮助。
原文链接：https://blog.csdn.net/u013183865/article/details/32165289