记录读取XML文件方式二

记录：使用SAX方式读取，在速度上要优于DOM

public class SchoolSax extends DefaultHandler {
    /**
     * 接收XML中所有有用的数据
     */
    private List<School> schoolList;
    /**
     * 临时变量
     */
    private School school;
    private SClass sClass;
    private Student student;

    public List<School> getSchoolList() {
        return schoolList;
    }


    /**
     * 文档接受文档开始的通知--此事件用于对象的初始化
     */
    @Override
    public void startDocument() throws SAXException {
        schoolList = new ArrayList<School>();

    }

    /**
     * 文档接受结束
     */
    @Override
    public void endDocument() throws SAXException {

    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        if (qName.equals(SchoolTag.SCHOOL)) {
            String schoolId = attributes.getValue(SchoolTag.ID);
            String schoolName = attributes.getValue(SchoolTag.NAME);
            school = new School(schoolId, schoolName);
        } else if (qName.equals(SchoolTag.CLASS)) {
            String sClassId = attributes.getValue(SchoolTag.ID);
            String sClassName = attributes.getValue(SchoolTag.NAME);
            sClass = new SClass(sClassId, sClassName, school);
        } else if (qName.equals(SchoolTag.STUDENT)) {
            String studentId = attributes.getValue(SchoolTag.ID);
            String studentName = attributes.getValue(SchoolTag.NAME);
            student = new Student(studentId, studentName, sClass);
        } else {
            System.out.println("其他的Tag：" + qName);
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if (qName.equals(SchoolTag.SCHOOL)) {
            this.schoolList.add(school);
        } else if (qName.equals(SchoolTag.CLASS)) {
            this.school.getsClassList().add(sClass);
        } else if (qName.equals(SchoolTag.STUDENT)) {
            this.sClass.getStudents().add(student);
        }
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {

    }
}

Test：

public class TestSax {

    public static void test(File file) throws Exception {
        SAXParserFactory factory = SAXParserFactory.newInstance();
        try {
            SAXParser saxParser = factory.newSAXParser();
            SchoolSax sax = new SchoolSax();
            //事件注册（允许多个接受者）
            saxParser.parse(file, sax);
            List<School> schoolList = sax.getSchoolList();
            for (School sch : schoolList) {
                System.out.println(sch.getId() + "--" + sch.getName());
                List<SClass> classList = sch.getsClassList();
                for (SClass sclass : classList) {
                    System.out.println(sclass.getId() + "--" + sclass.getName());
                    List<Student> studentList = sclass.getStudents();
                    for (Student stu : studentList) {
                        System.out.println(stu.getId() + "--" + stu.getName());
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    public static void main(String[] args) {
        try {
            String path = TestSax.class.getResource("/").toURI().getPath();
            String pathFileName = path + "\School.xml";
            TestSax.test(new File(pathFileName));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

同DOM相比，处理同一个XML文档，SAX用时：1s 459ms，DOM用时：4s 621ms