记录读取xml文件内容

记录下使用document类去读取xml文件内容

xml内容：

<?xml version="1.0" encoding = "UTF-8"?>
<schools>
    <school id="1" name="school1">
        <class id="11" name="class11">
            <student id="111" name="student111"/>
            <student id="112" name="student112"/>
            <student id="113" name="student113"/>
        </class>
        <class id="12" name="class12">
            <student id="121" name="student121"/>
            <student id="122" name="student122"/>
        </class>
        <class id="13" name="class13">
            <student id="131" name="student131"/>
            <student id="132" name="student132"/>
        </class>
    </school>
    <school id="2" name="school2">
        <class id="21" name="class21">
            <student id="211" name="student211"/>
        </class>
    </school>
</schools>

使用getElementsByTagName读取文件

定义学校类： 

public class School {

    private String name;
    private String id;
    private List<SClass> sClassList;

    public School(String name, String id) {
        this.name = name;
        this.id = id;
        sClassList = new ArrayList<SClass>();
    }

    public String getName() {
        return name;
    }

    public String getId() {
        return id;
    }

    public List<SClass> getsClassList() {
        return sClassList;
    }
}

定义班级类：

public class SClass {
    private String id;
    private String name;
    private School school;
    private List<Student> students;


    public SClass(String id, String name, School school) {
        this.id = id;
        this.name = name;
        this.school = school;
        students = new ArrayList<Student>();
        school.getsClassList().add(this);
    }

    public String getId() {
        return id;
    }


    public String getName() {
        return name;
    }


    public School getSchool() {
        return school;
    }


    public List<Student> getStudents() {
        return students;
    }
}

定义学生类：

public class Student {
    private String id;
    private String name;
    private SClass sClass;


    public Student(String id, String name, SClass sClass) {
        this.id = id;
        this.name = name;
        this.sClass = sClass;
        sClass.getStudents().add(this);
    }

    public String getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public SClass getsClass() {
        return sClass;
    }
}

定义读取xml类：

public class SchoolDOM {
    private Document document;

    public SchoolDOM(File file) {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();     //DOM树的解析器
        try {
            DocumentBuilder documentBuilder = factory.newDocumentBuilder();
            document = documentBuilder.parse(file);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * parse school.xml,返回所有学校、班级、学生的信息
     *
     * @return
     */
    public List<School> parseSchoolXml() {
        List<School> schools = null;
        if (document != null) {
            schools = new ArrayList<School>();
            NodeList schoolList = document.getElementsByTagName(SchoolTag.SCHOOL);          //学校的节点
            for (int i = 0; i < schoolList.getLength(); i++) {
                Node schoolNode = schoolList.item(i);
                if (schoolNode.getNodeType() == Node.ELEMENT_NODE) {
                    Element schoolElement = (Element) schoolNode;               //把节点（node）强转成元素（element）
                    String schoolID = schoolElement.getAttribute(SchoolTag.ID);
                    String schoolName = schoolElement.getAttribute(SchoolTag.NAME);
                    School school = new School(schoolID, schoolName);
                    schools.add(school);
                    NodeList classList = schoolElement.getChildNodes();                   //班级的节点
                    for (int j = 0; j < classList.getLength(); j++) {
                        Node classNode = classList.item(j);
                        if (classNode.getNodeType() == Node.ELEMENT_NODE) {
                            Element classElement = (Element) classNode;
                            String classID = classElement.getAttribute(SchoolTag.ID);
                            String className = classElement.getAttribute(SchoolTag.NAME);
                            SClass sclass = new SClass(classID, className, school);
                            NodeList studentList = classElement.getChildNodes();              //学生的节点
                            for (int k = 0; k < studentList.getLength(); k++) {
                                Node studentNode = studentList.item(k);
                                if (studentNode.getNodeType() == Node.ELEMENT_NODE) {
                                    Element studentElement = (Element) studentNode;
                                    String studentID = studentElement.getAttribute(SchoolTag.ID);
                                    String studentName = studentElement.getAttribute(SchoolTag.NAME);
                                    Student student = new Student(studentID, studentName, sclass);
                                }
                            }
                        }
                    }
                }
            }
        }

        return schools;
    }
}

定义Tag常量

public class SchoolTag {

    public static final String SCHOOL = "school";
    public static final String CLASS = "class";
    public static final String STUDENT = "student";
    public static final String ID = "id";
    public static final String NAME = "name";


}

测试方法

public class TestDom {
    public static void test() {
        try {
            String path = TestDom.class.getResource("/").toURI().getPath();
            String pathFileName = path + "\School.xml";
            File file = new File(pathFileName);
            SchoolDOM schoolDOM = new SchoolDOM(file);
            List<School> schools = schoolDOM.parseSchoolXml();
            for (School school : schools) {
                System.out.println(school.getId() + "---" + school.getName());
                List<SClass> classList = school.getsClassList();
                for (SClass sclass : classList) {
                    System.out.println(sclass.getId() + "--" + sclass.getName());
                    List<Student> students = sclass.getStudents();
                    for (Student student : students) {
                        StringBuilder stringBuilder = new StringBuilder();
                        stringBuilder.append(student.getId());
                        stringBuilder.append("--");
                        stringBuilder.append(student.getName());
                        System.out.println(stringBuilder);
                    }
                }
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    public static void main(String[] args) {
        TestDom.test();
    }
}

输出结果

school1---1
11--class11
111--student111
112--student112
113--student113
12--class12
121--student121
122--student122
13--class13
131--student131
132--student132
school2---2
21--class21
211--student211