Java对XML文件增删改查操作示例
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",
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", 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
http://www.zzvips.com/article/172760.html
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