关于读写XML文件到问题

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

<teaching-plan xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="plan.xsd">
	<course id="TC001">
		<course-name>高等数学</course-name>
		<class-hour>36</class-hour>
		<exam-form>考试</exam-form>
	</course>
	<course id="TC002">
		<course-name>计算机二级</course-name>
		<class-hour>48</class-hour>
		<exam-form>上机考试</exam-form>
	</course>
	<course id="TC003">
		<course-name>汇编语言</course-name>
		<class-hour>106</class-hour>
		<exam-form>考试</exam-form>
	</course>
</teaching-plan>

package 从网页搭建入门JavaWeb.步骤三JavaWeb入门.XML入门;

import java.util.List;

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

public class XMLreader {

	public static void main(String[] args) {
		// String file = "d:/compiling_software/eclipse/eclipse/workspace/慕课网/src/从网页搭建入门JavaWeb/步骤三JavaWeb入门/XML入门/plan.xml";
		String file = "src/从网页搭建入门JavaWeb/步骤三JavaWeb入门/XML入门/plan.xml";
		SAXReader reader = new SAXReader();
		try {
			Document document = reader.read(file);
			Element root = document.getRootElement();
			List<Element> elements = root.elements("course");
			for (Element ele : elements) {
				Attribute att = ele.attribute("id");
				String id = att.getText();
				Element name = ele.element("course-name");
				String course_name = name.getText();
				Element hour = ele.element("class-hour");
				String class_hour = hour.getText();
				Element form = ele.element("exam-form");
				String exam_form = form.getText();
				System.out.println("课程ID：" + id);
				System.out.println("课程名称：" + course_name);
				System.out.println("课程课时：" + class_hour);
				System.out.println("考核方式：" + exam_form);
			}
		} catch (DocumentException e) {
			// TODO 自动生成的 catch 块
			e.printStackTrace();
		}
	}

}