dom4j 解析 mybatis mapper xml 文件

01:

CarMapper.xml :

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="car">
    <!--insert sql：保存一个汽车信息-->
    <insert id="insertCar">
        insert into t_car
            (id,car_num,brand,guide_price,produce_time,car_type)
        values
            (null,#{carNum},#{brand},#{guidePrice},#{produceTime},#{carType})
    </insert>

</mapper>

package com.wsd;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;
import org.junit.Test;

import java.io.InputStream;
import java.util.List;

/**
 * @program: spring_learn
 * @description:
 * @author: Mr.Wang
 * @create: 2023-06-20 21:48
 **/
public class TestXml {

    @Test
    public void testParseMapperXml(){
        // 创建 SAXReader 对象
        SAXReader xReader = new SAXReader();

        //获取xml文件的输入流
        InputStream xmlInputStream = ClassLoader.getSystemClassLoader().getResourceAsStream("CarMapper.xml");

        Document document = null;

        try{
            //利用xml的输入流来解析xml文件，返回Document对象
            document = xReader.read(xmlInputStream);

            //获取根节点 mapper标签
            String xpath = "/mapper";
            /*selectSingleNode 返回类型为 Node,
            将其强转为 Element（Element 是 Node 的子类），为了使用Element更多的方法
             */
            Element mapperElement = (Element) document.selectSingleNode(xpath);
            System.out.println(mapperElement);
            //获取属性值
            String namespace = mapperElement.attributeValue("namespace");
            System.out.println(namespace);
            
        }
        catch ( DocumentException e){
            e.printStackTrace();
        }

    }


}

02:

Car pojo :

package com.wsd.pojo;

/**
 * @program: spring_learn
 * @description:
 * @author: Mr.Wang
 * @create: 2023-06-17 21:53
 **/
public class Car {

    private Long id;
    private String carNum;
    private String brand;
    private Double guidePrice;
    private String produceTime;
    private String carType;

    @Override
    public String toString() {
        return "Car{" +
                "id=" + id +
                ", carNum='" + carNum + '\'' +
                ", brand='" + brand + '\'' +
                ", guidePrice=" + guidePrice +
                ", produceTime='" + produceTime + '\'' +
                ", carType='" + carType + '\'' +
                '}';
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getCarNum() {
        return carNum;
    }

    public void setCarNum(String carNum) {
        this.carNum = carNum;
    }

    public String getBrand() {
        return brand;
    }

    public void setBrand(String brand) {
        this.brand = brand;
    }

    public Double getGuidePrice() {
        return guidePrice;
    }

    public void setGuidePrice(Double guidePrice) {
        this.guidePrice = guidePrice;
    }

    public String getProduceTime() {
        return produceTime;
    }

    public void setProduceTime(String produceTime) {
        this.produceTime = produceTime;
    }

    public String getCarType() {
        return carType;
    }

    public void setCarType(String carType) {
        this.carType = carType;
    }
}

CarMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="car">
    <!--insert sql：保存一个汽车信息-->
    <insert id="insertCar">
        insert into t_car
            (id,car_num,brand,guide_price,produce_time,car_type)
        values
            (null,#{carNum},#{brand},#{guidePrice},#{produceTime},#{carType})
    </insert>

    <select id="selectCarAll" resultType="com.wsd.pojo.Car">
        <!--记得使用as起别名，让查询结果的字段名和java类的属性名对应上-->
        select
        brand, guide_price as guidePrice, produce_time as produceTime, car_type as carType
        from
        t_car
    </select>

</mapper>

package com.wsd;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;
import org.junit.Test;

import java.io.InputStream;
import java.util.List;

/**
 * @program: spring_learn
 * @description:
 * @author: Mr.Wang
 * @create: 2023-06-20 21:48
 **/
public class TestXml {

    @Test
    public void testParseMapperXml(){
        // 创建 SAXReader 对象
        SAXReader xReader = new SAXReader();

        //获取xml文件的输入流
        InputStream xmlInputStream = ClassLoader.getSystemClassLoader().getResourceAsStream("CarMapper.xml");

        Document document = null;

        try{
            //利用xml的输入流来解析xml文件，返回Document对象
            document = xReader.read(xmlInputStream);

            //获取根节点 mapper标签
            String xpath = "/mapper";
            /*selectSingleNode 返回类型为 Node,
            将其强转为 Element（Element 是 Node 的子类），为了使用Element更多的方法
             */
            Element mapperElement = (Element) document.selectSingleNode(xpath);

            //获取属性值
            String namespace = mapperElement.attributeValue("namespace");

            //获取所有 子 元素
            List<Element> elements = mapperElement.elements();

            //遍历
            elements.forEach(
                    element -> {
                        //获取 id 属性
                        String id = element.attributeValue("id");
                        System.out.println("id = " + id);

                        //获取 resultType 属性,没有该属性 返回 null
                        String resultType = element.attributeValue("resultType");
                        System.out.println("resultType = " + resultType);

                        //获取标签的文本内容(sql语句),并且去除前后的空格
                        String sql = element.getTextTrim();
                        System.out.println("sql :" +  sql);

                    }
            );

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

    }

}

"C:\Program Files\Java\jdk-17\bin\java.exe" -ea -Didea.test.cyclic.buffer.size=1048576 -Didea.launcher.port=62271 "-Didea.launcher.bin.path=C:\Minecloud\IDEA_2019\IntelliJ IDEA 2019.1\bin" -Dfile.encoding=UTF-8 -classpath "C:\Minecloud\IDEA_2019\IntelliJ IDEA 2019.1\lib\idea_rt.jar;C:\Minecloud\IDEA_2019\IntelliJ IDEA 2019.1\plugins\junit\lib\junit-rt.jar;C:\Minecloud\IDEA_2019\IntelliJ IDEA 2019.1\plugins\junit\lib\junit5-rt.jar;C:\Minecloud\IDEA_workspace\spring_learn\parsexml\target\test-classes;C:\Minecloud\IDEA_workspace\spring_learn\parsexml\target\classes;C:\Minecloud\maven_3.9\apache-maven-3.9.0\repo\org\dom4j\dom4j\2.1.3\dom4j-2.1.3.jar;C:\Minecloud\maven_3.9\apache-maven-3.9.0\repo\jaxen\jaxen\1.2.0\jaxen-1.2.0.jar;C:\Minecloud\maven_3.9\apache-maven-3.9.0\repo\junit\junit\4.13.2\junit-4.13.2.jar;C:\Minecloud\maven_3.9\apache-maven-3.9.0\repo\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar" com.intellij.rt.execution.application.AppMainV2 com.intellij.rt.execution.junit.JUnitStarter -ideVersion5 -junit4 com.wsd.TestXml,testParseMapperXml
id = insertCar
resultType = null
sql :insert into t_car (id,car_num,brand,guide_price,produce_time,car_type) values (null,#{carNum},#{brand},#{guidePrice},#{produceTime},#{carType})
id = selectCarAll
resultType = com.wsd.pojo.Car
sql :select brand, guide_price as guidePrice, produce_time as produceTime, car_type as carType from t_car

Process finished with exit code 0

03：

package com.wsd;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;
import org.junit.Test;

import java.io.InputStream;
import java.util.List;

/**
 * @program: spring_learn
 * @description:
 * @author: Mr.Wang
 * @create: 2023-06-20 21:48
 **/
public class TestXml {

    @Test
    public void testParseMapperXml(){
        // 创建 SAXReader 对象
        SAXReader xReader = new SAXReader();

        //获取xml文件的输入流
        InputStream xmlInputStream = ClassLoader.getSystemClassLoader().getResourceAsStream("CarMapper.xml");

        Document document = null;

        try{
            //利用xml的输入流来解析xml文件，返回Document对象
            document = xReader.read(xmlInputStream);

            //获取根节点 mapper标签
            String xpath = "/mapper";
            /*selectSingleNode 返回类型为 Node,
            将其强转为 Element（Element 是 Node 的子类），为了使用Element更多的方法
             */
            Element mapperElement = (Element) document.selectSingleNode(xpath);

            //获取属性值
            String namespace = mapperElement.attributeValue("namespace");

            //获取所有 子 元素
            List<Element> elements = mapperElement.elements();

            //遍历
            elements.forEach(
                    element -> {
                        //获取 id 属性
                        String id = element.attributeValue("id");
                        System.out.println("id = " + id);

                        //获取 resultType 属性,没有该属性 返回 null
                        String resultType = element.attributeValue("resultType");
                        System.out.println("resultType = " + resultType);

                        //获取标签的文本内容(sql语句),并且去除前后的空格
                        String mapperSql = element.getTextTrim();
                        System.out.println("mapperSql :" +  mapperSql);

                        //将 #{} 替换为 ?,"#\\{[0-9A-Za-z_$]*}" 是匹配 #{} 的正则表达式
                        String preSql = mapperSql.replaceAll("#\\{[0-9A-Za-z_$]*}", "?");
                        System.out.println("preSql    :" + preSql);

                    }
            );

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

    }
}

id = insertCar
resultType = null
mapperSql :insert into t_car (id,car_num,brand,guide_price,produce_time,car_type) values (null,#{carNum},#{brand},#{guidePrice},#{produceTime},#{carType})
preSql :insert into t_car (id,car_num,brand,guide_price,produce_time,car_type) values (null,?,?,?,?,?)
id = selectCarAll
resultType = com.wsd.pojo.Car
mapperSql :select brand, guide_price as guidePrice, produce_time as produceTime, car_type as carType from t_car
preSql :select brand, guide_price as guidePrice, produce_time as produceTime, car_type as carType from t_car