如何在使用 sax 解析器时获取循环外的节点

Question

我需要使用java中的SAX解析器来解析文档。如果我使用传统上实现 startElement、endElement 和字符方法的 DefaultHandler 类，我就能够打印所有节点值。如何访问for循环之外的节点 我的示例 XML 是：

<root>
<location>USA</location>
<Employees>
    <Employee id="1">
        <age>29</age>
        <name>Pankaj</name>
        <gender>Male</gender>
        <role>Java Developer</role>
    </Employee>
    <Employee id="2">
        <age>35</age>
        <name>Lisa</name>
        <gender>Female</gender>
        <role>CEO</role>
    </Employee>
</root>

这是我的java代码，每个员工都有for循环

public class XMLParserSAX {
    public static void main(String[] args) {
        SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();
        try {
            SAXParser saxParser = saxParserFactory.newSAXParser();
            MyHandler handler = new MyHandler();
            saxParser.parse(new File("/Users/yashvanth/IdeaProjects/parsing/src/staff.xml"), handler);
            //Get Employees list
            List<Employee> empList = handler.getEmpList();
            //print employee information
            for(Employee emp : empList)
                System.out.println(emp);
        } catch (ParserConfigurationException | SAXException | IOException e) {
            e.printStackTrace();
        }
    }
}

和我的处理程序类

public class MyHandler extends DefaultHandler {

    // List to hold Employees object
    private List<Employee> empList = null;
    private Employee emp = null;
    private StringBuilder data = null;

    // getter method for employee list
    public List<Employee> getEmpList() {
        return empList;
    }

    boolean bAge = false;
    boolean bName = false;
    boolean bGender = false;
    boolean bRole = false;

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

        if (qName.equalsIgnoreCase("Employee")) {
            // create a new Employee and put it in Map
            String id = attributes.getValue("id");
            // initialize Employee object and set id attribute
            emp = new Employee();
            emp.setId(Integer.parseInt(id));
            // initialize list
            if (empList == null)
                empList = new ArrayList<>();
        } else if (qName.equalsIgnoreCase("name")) {
            // set boolean values for fields, will be used in setting Employee variables
            bName = true;
        } else if (qName.equalsIgnoreCase("age")) {
            bAge = true;
        } else if (qName.equalsIgnoreCase("gender")) {
            bGender = true;
        } else if (qName.equalsIgnoreCase("role")) {
            bRole = true;
        }
        // create the data container
        data = new StringBuilder();
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if (bAge) {
            // age element, set Employee age
            emp.setAge(Integer.parseInt(data.toString()));
            bAge = false;
        } else if (bName) {
            emp.setName(data.toString());
            bName = false;
        } else if (bRole) {
            emp.setRole(data.toString());
            bRole = false;
        } else if (bGender) {
            emp.setGender(data.toString());
            bGender = false;
        }

        if (qName.equalsIgnoreCase("Employee")) {
            // add Employee object to list
            empList.add(emp);
        }
    }

    @Override
    public void characters(char ch[], int start, int length) throws SAXException {
        data.append(new String(ch, start, length));
    }
}

我的输出为

Employee:: ID=1 Name=Pankaj Age=29 Gender=Male Role=Java Developer
Employee:: ID=2 Name=Lisa Age=35 Gender=Female Role=CEO

如何读取属性并添加到输出中，如下所示

location:USA
Employee:: ID=1 Name=Pankaj Age=29 Gender=Male Role=Java Developer
Employee:: ID=2 Name=Lisa Age=35 Gender=Female Role=CEO

Answer 1

至少，你可以像

handler.getEmpList()

一样实现它：

public static void main(String[] args) {
        ...
            String location = handler.getLocation();
            System.out.println("Location: " + location);
            // print employees
}

处理者：

public class MyHandler extends DefaultHandler {
    ....
    private boolean locationTagOpen = false;
    private String location = null;
    public String getLocation() {
        return location;
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {

        ...
        else if (qName.equalsIgnoreCase("location")) {
            locationTagOpen = true;
        }
        ...
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
        if (locationTagOpen) {
            location = data.toString();
            locationTagOpen = false;
        } 
        ...
    }
}