java使用dom4j操作xml示例代码

dom4j是一个非常优秀的java xml api，具有性能优异、功能强大和极端易用使用的特点，同时它也是一个开放源工具。可以在这个地址http://dom4j.sourceforge.net进行下载。
这里我们使用到的dom4j是dom4j-1.6.1这个版本，我们只需要使用到如下两个jar包：

dom4j-1.6.1.jar
commons-io-2.4.jar

1、dom4j读取xml字符串

import org.dom4j.document;
import org.dom4j.documentexception;
import org.dom4j.documenthelper;
import org.dom4j.element;

public class testreadxmlstring {
    public static void main(string[] args) throws documentexception {
        string readline = "<?xml version=\"1.0\" encoding=\"utf-8\"?><students><student sid=\"001\"> <id>001</id><name>灰机</name> <age>18</age> </student></students>";
        document document = documenthelper.parsetext(readline);
        element rootelm = document.getrootelement();
        system.out.println("rootelement:  " + rootelm.getname());
        element student = rootelm.element("student");
        element id = student.element("id");
        element name = student.element("name");
        element age = student.element("age");
        system.out.println(id.gettext());
        system.out.println(name.gettext());
        system.out.println(age.gettext());
    }
}

2、dom4j创建xml文件

import org.dom4j.document;
import org.dom4j.documenthelper;
import org.dom4j.element;
import org.dom4j.io.outputformat;
public class testwritexmlstring {
    public static void main(string[] args) {
        outputformat format = outputformat.createprettyprint();
        // 1. 构造空的document
        document doc = documenthelper.createdocument();
        doc.addcomment("this is a comment");
        // 2. 构造根元素
        element rootelmt = doc.addelement("users");
        rootelmt.addnamespace("test", "www.test.com");

        element userelmt = rootelmt.addelement("user");
        userelmt.addattribute("number", "1001");
        userelmt.addelement("name").settext("zhangsan");
        userelmt.addelement("age").settext("20");
        userelmt.addelement("gender").settext("mail");

        element userelmt2 = rootelmt.addelement("user");
        userelmt.addattribute("number", "1002");
        userelmt2.addelement("name").settext("zhangsan");
        userelmt2.addelement("age").settext("20");
        userelmt2.addelement("gender").settext("mail");

        system.out.println(doc.asxml().replaceall("\n", ""));
    }
}

3、读取或写xml文件

读取xml文件

saxreader reader = new saxreader();
string path = "e:/workspaces/myeclipse 8.6/xmltest/file/student.xml";
document document = reader.read(new file(path));

写xml文件

outputformat format = outputformat.createprettyprint();
format.setencoding("utf-8");// 设置xml文件的编码格式
string filepath = "e:/workspaces/myeclipse 8.6/xmltest/file/student.xml";
document document = documenthelper.createdocument();
doc.addcomment("this is a comment");

/创建document内容

xmlwriter writer = new xmlwriter(new filewriter(filepath), format);//写入指定的文件
writer.write(document);
 writer.close();