Question

如何使用DOM解析复杂的XML文件？我需要访问每个年级的孩子，但我正在获取xml文件中的所有课程。如何访问成绩，孩子，学生和教师元素。

public SchoolM readFileNBuildModel(String filePath) {
    File file = new File(filePath);
    if (file.exists()) {
        AppLauncher.getLog().log(Level.INFO, " File Exist : " + filePath,filePath);
        try {
            AppLauncher.getLog().log(Level.INFO, " Parsing File : " + filePath,filePath);
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder documentBuilder;
            documentBuilder = dbf.newDocumentBuilder();
            Document doc = documentBuilder.parse(file);
            doc.getDocumentElement().normalize();
            Element schoolNode = doc.getDocumentElement();
            NodeList gradeList = doc.getElementsByTagName("grade");
            SortedSet<GradeM> gradeSet = new TreeSet<GradeM>();
            for (int temp = 0; temp < gradeList.getLength(); temp++) {
                Node gradeNode = gradeList.item(temp);
                Element gradeElemet = (Element) gradeNode;
                GradeM gradeM = new GradeM(gradeElemet.getAttribute("id"));
                SortedSet<ClassM> classSet = new TreeSet<ClassM>();
                NodeList classList = doc.getElementsByTagName("classroom");
                for (int classIndex = 0; classIndex < classList.getLength(); classIndex++) {
                    Node classNode = classList.item(classIndex);
                    Element classElement = (Element) classNode;
                    ClassM classM = new ClassM(classElement.getAttribute(CSVColumnAttributeEnum.CLASSROOM_ID.getXmlMapColumnName()),
                            classElement.getAttribute(CSVColumnAttributeEnum.CLASSROOM_NAME.getXmlMapColumnName()));
                    SortedSet<TeacherM> teacherSet = new TreeSet<TeacherM>();
                    SortedSet<StudentM> studentSet = new TreeSet<StudentM>();
                    NodeList teacherList = doc.getElementsByTagName("teacher");
                    NodeList studentList = doc.getElementsByTagName("student");
                    for (int studentIndex = 0; studentIndex < studentList.getLength(); studentIndex++) {
                        Node studentNode = studentList.item(studentIndex);
                        Element studentElement = (Element) studentNode;
                        if(studentElement != null){
                            StudentM studentM = new StudentM(studentElement.getAttribute(CSVColumnAttributeEnum.STUDENT_ID.getXmlMapColumnName()),
                                studentElement.getAttribute(CSVColumnAttributeEnum.STUDENT_FIRST_NAME.getXmlMapColumnName()), studentElement.getAttribute(CSVColumnAttributeEnum.STUDENT_LAST_NAME.getXmlMapColumnName()),
                                studentElement.getAttribute(CSVColumnAttributeEnum.STUDENT_GRADE.getXmlMapColumnName()));
                            studentSet.add(studentM);
                        }
                    }
                    for (int teacherIndex = 0; teacherIndex < teacherList.getLength(); teacherIndex++) {
                        Node teacherNode = teacherList.item(classIndex);
                        Element teacherElement = (Element) teacherNode;
                        if(teacherElement != null){
                            TeacherM teacherM = new TeacherM(teacherElement.getAttribute(CSVColumnAttributeEnum.TEACHER1_ID.getXmlMapColumnName()),
                                teacherElement.getAttribute(CSVColumnAttributeEnum.TEACHER1_LAST_NAME.getXmlMapColumnName()), teacherElement.getAttribute(CSVColumnAttributeEnum.TEACHER1_FIRST_NAME.getXmlMapColumnName()));
                            teacherSet.add(teacherM);
                        }
                    }
                    classM.setStudentSet(studentSet);
                    classM.setTeacherSet(teacherSet);
                    classSet.add(classM);
                }
                gradeM.setClassSet(classSet);
                gradeSet.add(gradeM);
            }
            SchoolM schoolM = new SchoolM(schoolNode.getAttribute("id"), schoolNode.getAttribute("schoolName"),gradeSet);
            return schoolM;
        } catch (ParserConfigurationException e) {
            AppLauncher.getLog().log(Level.SEVERE, " File Conversion failed because of  : /n" + e.toString());
        } catch (SAXException e) {
            AppLauncher.getLog().log(Level.SEVERE, " File Conversion failed because of  : /n" + e.toString());
        } catch (IOException e) {
            AppLauncher.getLog().log(Level.SEVERE, " File Conversion failed because of  : /n" + e.toString());
        }
    }else{
        AppLauncher.getLog().log(Level.WARNING, " File Does Not Exist : " + filePath,filePath);
    }
    return new SchoolM();

XML文件：

<grade id="1">
    <classroom id="101" name="Mrs. Jones' Math Class">
        <teacher id="10100000001" first_name="Barbara" last_name="Jones"/>

        <student id="10100000010" first_name="Michael" last_name="Gil"/>
        <student id="10100000011" first_name="Kimberly" last_name="Gutierrez"/>
        <student id="10100000013" first_name="Toby" last_name="Mercado"/>
        <student id="10100000014" first_name="Lizzie" last_name="Garcia"/>
        <student id="10100000015" first_name="Alex" last_name="Cruz"/>
    </classroom>


    <classroom id="102" name="Mr. Smith's PhysEd Class">
        <teacher id="10200000001" first_name="Arthur" last_name="Smith"/>
        <teacher id="10200000011" first_name="John" last_name="Patterson"/>

        <student id="10200000010" first_name="Nathaniel" last_name="Smith"/>
        <student id="10200000011" first_name="Brandon" last_name="McCrancy"/>
        <student id="10200000012" first_name="Elizabeth" last_name="Marco"/>
        <student id="10200000013" first_name="Erica" last_name="Lanni"/>
        <student id="10200000014" first_name="Michael" last_name="Flores"/>
        <student id="10200000015" first_name="Jasmin" last_name="Hill"/>
        <student id="10200000016" first_name="Brittany" last_name="Perez"/>
        <student id="10200000017" first_name="William" last_name="Hiram"/>
        <student id="10200000018" first_name="Alexis" last_name="Reginald"/>
        <student id="10200000019" first_name="Matthew" last_name="Gayle"/>
    </classroom>
    <classroom id="103" name="Brian's Homeroom">
        <teacher id="10300000001" first_name="Brian" last_name="O'Donnell"/>
    </classroom>
</grade>

Answer 1

对您正在处理的元素使用getElementsByTagName方法，例如使用gradeElemet.getElementByTagName("classroom")代替doc.getElementsByTagName("classroom")。然后在所有嵌套循环中继续使用该方法在当前处理的元素上调用方法，而不是在整个文档上调用。

如何使用DOM解析复杂的XML文件？

1 个答案: