Java之XML操作：从XML中直接获取数据

　　本文介绍如何将数据记录在XML文件中，然后通过DOM4J直接从XML中读取到数据。

依赖包：

<dependency>
    <groupId>dom4j</groupId>
    <artifactId>dom4j</artifactId>
    <version>1.6.1</version>
</dependency>

工具类代码：

package testTraffic.utils;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * XmlUtils class
 *
 * @author gongxingrui
 * @date 2018-12-07
 **/
public class XmlUtils {


    public static Document readXml(String filePath) throws DocumentException {
        return readXml(new File(filePath));
    }


    public static Document readXml(File file) throws DocumentException {
        SAXReader reader = new SAXReader();
        return reader.read(file);
    }

    public static Document readXml(InputStream inputStream) throws DocumentException {
        SAXReader reader = new SAXReader();
        return reader.read(inputStream);
    }


    public static Document readXmlFromResources(String resource) throws DocumentException, IOException, URISyntaxException {
        SAXReader reader = new SAXReader();
        return reader.read(ResourcesUtils.getResourceAsFile(resource));
    }


    public static String getAttribute(Element element, String attrName) {
        return element.attributeValue(attrName);
    }

    public static String getText(Element element) {
        return element.getText();
    }

    public static List<Element> getElements(Element element, String tagName) {
        return element.elements(tagName);
    }

    /**
     * 根据节点名称获取子节点数据
     */
    public static String getElementText(String resource, String qName) throws Exception {
        Element root = readXmlFromResources(resource).getRootElement();
        String text = root.elementText(qName);
        return text.trim();
    }

    /**
     * 根据节点名称获取子节点的子节点数据
     */
    public static String getElementText(String resource, String qName, String SubQName) throws Exception {
        Element root = readXmlFromResources(resource).getRootElement();
        String text = root.element(qName).elementText(SubQName);
        return text.trim();
    }

    /**
     * 根据节点名称获取子节点的子节点的数据列表
     */
    public static List<String> getElementTextList(String resource, String qName) throws Exception {
        List<Element> elementList = readXmlFromResources(resource).getRootElement().element(qName).elements();
        List<String> list = new ArrayList<>();
        for (Element e : elementList) {
            list.add(e.getTextTrim());
        }
        return list;
    }


}

测试代码：

    @Test
    public void testXML6() throws Exception {
        String path2 = "shelby/data/sql/demo/sql2.xml";
        String s = XmlUtils.getElementText(path2, "insert_1");
        logger.info(s);

        List<String> list = XmlUtils.getElementTextList(path2, "del_group");
        logger.info(list);

        String s2 = XmlUtils.getElementText(path2, "del_group_2", "del_2");
        logger.info(s2);
    }   

测试结果：

2019-01-28 16:13:14.746 INFO  testTraffic.testDemo.testXmlDemo testXML6 : insert into `t_admin_user` (`id`, `user_name`, `user_password`, `del_flag`, `create_time`, `update_time`)
        VALUES( null,'testuser','testuser123','0','2019-01-21 19:43:58','2019-01-22 19:44:03');
2019-01-28 16:13:14.763 INFO  testTraffic.testDemo.testXmlDemo testXML6 : [delete from t_admin_user WHERE user_name = 'testuser';, delete from t_admin_user WHERE user_name = 'testuser2';]
2019-01-28 16:13:14.768 INFO  testTraffic.testDemo.testXmlDemo testXML6 : delete from t_admin_user WHERE user_name = 'testuser2';

Process finished with exit code 0

XML文档：

<?xml version="1.0" encoding="UTF-8"?>
<mybatisGroup id="预置数据语句">
    <del_1 id="del_1" type="delete">
        delete from t_admin_user WHERE user_name = 'testuser';
    </del_1>
    <del_2 id="del_2" type="delete">
        delete from t_admin_user WHERE user_name = 'testuser2';
    </del_2>
    <insert_1 id="insert_1" type="insert">
        insert into `t_admin_user` (`id`, `user_name`, `user_password`, `del_flag`, `create_time`, `update_time`)
        VALUES( null,'testuser','testuser123','0','2019-01-21 19:43:58','2019-01-22 19:44:03');
    </insert_1>

    <del_group>
        <statement>
            delete from t_admin_user WHERE user_name = 'testuser';
        </statement>
        <statement>
            delete from t_admin_user WHERE user_name = 'testuser2';
        </statement>
    </del_group>

    <del_group_2>
        <del_1>
            delete from t_admin_user WHERE user_name = 'testuser';
        </del_1>
        <del_2>
            delete from t_admin_user WHERE user_name = 'testuser2';
        </del_2>
        <del_3>
            delete from t_admin_user WHERE user_name = 'testuser3';
        </del_3>
    </del_group_2>

</mybatisGroup>