JAVA XML转对象 对象转XML

大家好，又见面了，我是你们的朋友全栈君。

在网上看了许多XML跟Obj互相转换的Demo，但是都很复杂，现在推荐一个极度简单好理解的XML和Obj互转的例子：

JacksonXML，只需要简单的几个注解就能完成XML和Obj的相互转换

假设有如下xml报文：

<?xml version="1.0" encoding="utf-8"?>
<msgbody>
  <StringList>
    <mx>
      <paramA>Aone</paramA>
      <paramB>Bone</paramB>
    </mx>
    <mx>
      <paramA>Atow</paramA>
      <paramB>Atow</paramB>
    </mx>
  </StringList>
  <serverId>serv10000000156</serverId>
  <name>张三</name>
  <age>女</age>
  <address>武汉市</address>
</msgbody>

分析这段报文，首先报文头是 <?xml version=”1.0″ encoding=”utf-8″?>

然后有<msgbody>标签包住报文体，然后有属性serverId，name，age，address 和 一个列表，列表中的每一个单位用<mx>标签分隔开来，最后每个单位中都有paramA 和 paramB 两个属性。

准备工作添加pom依赖：

<dependency>
	<groupId>com.fasterxml.jackson.dataformat</groupId>
	<artifactId>jackson-dataformat-xml</artifactId>
	<version>2.9.0</version>
</dependency>
<dependency>
	<groupId>com.fasterxml.woodstox</groupId>
	<artifactId>woodstox-core</artifactId>
	<version>5.1.0</version>
</dependency>

那么第一步我们创建与这个报文对应的class：

package com.symphony.springbootdata.demo.xmlTest;

import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;

import java.util.List;

/**
 * 报文对应class
 *
 * @author <a href="***@163.com">***</a>
 * @version 1.0.0
 * @since 1.0.0
 * <p>
 * Created at 2018/9/30
 */

@JacksonXmlRootElement(localName = "msgbody")
public class Person {
    @JacksonXmlProperty(localName = "serverId")
    private String serverId;
    @JacksonXmlProperty(localName = "name")
    private String name;
    @JacksonXmlProperty(localName = "age")
    private String age;
    @JacksonXmlProperty(localName = "address")
    private String address;
    @JacksonXmlElementWrapper(localName = "StringList")
    private List<Clazz> mx;

    public Person() {
    }

    public Person(String serverId, String name, String age, String address, List<Clazz> mx) {
        this.serverId = serverId;
        this.name = name;
        this.age = age;
        this.address = address;
        this.mx = mx;
    }

    public String getServerId() {
        return serverId;
    }

    public void setServerId(String serverId) {
        this.serverId = serverId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public List<Clazz> getMx() {
        return mx;
    }

    public void setMx(List<Clazz> mx) {
        this.mx = mx;
    }

    @Override
    public String toString() {
        return "Person{" +
                "serverId='" + serverId + '\'' +
                ", name='" + name + '\'' +
                ", age='" + age + '\'' +
                ", address='" + address + '\'' +
                ", mx=" + mx +
                '}';
    }
}

package com.symphony.springbootdata.demo.xmlTest;

import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;

/**
 * 报文中列表对应class
 *
 * @author <a href="***@163.com">***</a>
 * @version 1.0.0
 * @since 1.0.0
 * <p>
 * Created at 2018/10/9
 */
@JacksonXmlRootElement(localName = "MX")
public class Clazz {
    @JacksonXmlProperty(localName = "paramA")
    private String a;
    @JacksonXmlProperty(localName = "paramB")
    private String b;

    public String getA() {
        return a;
    }

    public void setA(String a) {
        this.a = a;
    }

    public String getB() {
        return b;
    }

    public void setB(String b) {
        this.b = b;
    }

    @Override
    public String toString() {
        return "Clazz{" +
                "a='" + a + '\'' +
                ", b='" + b + '\'' +
                '}';
    }
}

创建好对应的class之后，开始XML与Obj的转换

package com.symphony.springbootdata.demo.xmlTest;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import org.junit.Test;

import javax.xml.bind.JAXBException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * XML Obj 互相转换
 *
 * @author <a href="mailto:***@163.com">***</a>
 * @version 1.0.0
 * @since 1.0.0
 * <p>
 * Created at 2018/9/30
 */
public class ObjToXmlUtils {

    public static void main(String[] args) throws JsonProcessingException {
        List<Clazz> mx = new ArrayList<>();
        Clazz clazz = new Clazz();
        clazz.setA("Aone");
        clazz.setB("Bone");
        mx.add(clazz);
        clazz = new Clazz();
        clazz.setA("Atow");
        clazz.setB("Atow");
        mx.add(clazz);

        ObjectMapper mapper = new XmlMapper();
        String s = mapper.writeValueAsString(new Person("serv10000000156", "张三", "女", "武汉市", mx));
        System.out.println("<?xml version=\"1.0\" encoding=\"utf-8\"?>" + s);
    }

    @Test
    public void xmlToObj() throws JAXBException, IOException {
        String xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?><msgbody><StringList><mx><paramA>Aone</paramA><paramB>Bone</paramB></mx><mx><paramA>Atow</paramA><paramB>Atow</paramB></mx></StringList><serverId>serv10000000156</serverId><name>张三</name><age>女</age><address>武汉市</address></msgbody>\n";
        ObjectMapper mapper = new XmlMapper();
        Object po = null;
        po = mapper.readValue(xml, Person.class);
        System.out.println(po.toString());
    }
}

综上，我们看到了注解

　@JacksonXmlElementWrapper：指定用于包装List和Map属性的XML元素
　@JacksonXmlProperty：为属性指定XML名称空间和本地名称; 以及是否将属性写为XML元素或属性
　@JacksonXmlRootElement：指定用于包装根元素的XML元素
　@JacksonXmlText：指定当前这个值，没有xml标签包裹