选型： json-lib.jar可以做，但是太老了，抛弃； fast JSON 完全没有xml相关功能； staxon经测试不能用。 最终选用jackson来主要实现。

JDK为1.8，如果低于1.8，则只需要将try-catch的语法改回传统书写方式。

目前的实现，传参和回参都是String，如果想JSONObject对象和XML对象互转，只需要再包一层就可以多2个或4个方法。

一、依赖

pom.xml

<dependency>

<groupId>com.fasterxml.jackson.core</groupId>

<artifactId>jackson-core</artifactId>

<version>2.8.8</version>

</dependency>

<dependency>

<groupId>com.fasterxml.jackson.core</groupId>

<artifactId>jackson-databind</artifactId>

<version>2.8.8</version>

</dependency>

<dependency>

<groupId>com.fasterxml.jackson.dataformat</groupId>

<artifactId>jackson-dataformat-xml</artifactId>

<version>2.8.8</version>

</dependency>

<dependency>

<groupId>com.alibaba</groupId>

<artifactId>fastjson</artifactId>

<vers io n>1.2.33</version>

</dependency>

二、实现

package com.kapu.common.utility;

import java.io.IOException;

import java.io.StringWriter;

import org.apache.commons.lang3.StringUtils;

import com.alibaba.fastjson. json ;

import com.alibaba.fastjson.JSONObject;

import com.fasterxml.jackson.core.JsonGenerator;

import com.fasterxml.jackson.core.JsonParseException;

import com.fasterxml.jackson.core.JsonParser;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.fasterxml.jackson.dataformat.xml.XmlMapper;

public class JsonXmlUtil {

private static final String XML_PREFIX = “<?xml version=”1.0″ encoding=”UTF-8″ ?>”;

private static final String XML_PREFIX_HEAD = “<?”;

private static final String XML_PREFIX_TAIL = “?>”;

private static final String XML_ROOT_START = “<xml>”;

private static final String XML_ROOT_END = “</xml>”;

/**

* json string convert to xml string

* @throws IOException

* @throws JsonParseException

*/

public static String json2xml(String json) throws IOException {

if (StringUtils.isEmpty(json)) {

return null;

}

JSONObject jsonObject = JSON.parseObject(json);

StringWriter w = new StringWriter();

XmlMapper xmlMapper = new XmlMapper();

xmlMapper.writeValue(w, jsonObject);

String xml = w. toString ();

xml = xml.replaceAll(“<JSONObject>”, “”).replaceAll(“</JSONObject>”, “”);

xml = XML_PREFIX + xml;

return xml;

}

/**

* xml string convert to json string

* @throws IOException

*/

public static String xml2json(String xml) throws IOException {

if(StringUtils.isEmpty(xml)) {

return null;

}

if(xml.indexOf(XML_PREFIX_HEAD) > -1 && xml.indexOf(XML_PREFIX_TAIL) > -1){

xml = xml.substring(xml.indexOf(XML_PREFIX_TAIL) + 2);

}

xml = XML_ROOT_START + xml + XML_ROOT_END;

StringWriter w = new StringWriter();

try(JsonParser jp = new XmlMapper().getFactory().createParser(xml);JsonGenerator jg = new ObjectMapper().getFactory().createGenerator(w);){

while (jp.nextToken() != null) {

jg.copyCurrentEvent(jp);

}

}

return w.toString();

}

}

三、测试

package com.kapu.common.base;

import java.io.IOException;

import org.junit.Test;

import com.kapu.common.utility.JsonXmlUtil;

import com.alibaba.fastjson.JSONObject;

public class JsonXml {

@Test

public void testJson2Xml() {

JSONObject meta = new JSONObject();

meta.put(“from”, “WEB”);

meta.put(“token”, “sdfa4sdf4as5d4f8a4sd8f4asdf”);

meta.put(“timestamp”, System.currentTimeMillis());

JSONObject data = new JSONObject();

data.put(“id”, 123);

data.put(“name”, “one-two-three”);

data.put(“desc”, “this is a number list”);

JSONObject json = new JSONObject();

json.put(“meta”, meta);

json.put(“data”, data);

json.put(” aaa “, “aaaaaa”);

System.out.println(json);

String xml = null;

try {

xml = JsonXmlUtil.json2xml(json.toJSONString());

} catch (Throwable e) {

e.printStackTrace();

}

System.out.println(xml);

}

@Test

public void testXml2Json() {

String xml = “<?xml version=”1.0″ encoding=”UTF-8″ ?><aaa>aaaaaa</aaa><data><name>one-two-three</name> <id>123</id><desc>thisisanumberlist</desc></data><meta><from>WEB</from><token>sdfa4sdf4as5d4f8a4sd8f4asdf</token><timestamp>1536049559684</timestamp></meta>”;

try {

String json = JsonXmlUtil.xml2json(xml);

System.out.println(json);

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

@Test

public void testJson2Xml2Json() throws IOException {

JSONObject meta = new JSONObject();

meta.put(“from”, “WEB”);

meta.put(“token”, “sdfa4sdf4as5d4f8a4sd8f4asdf”);

meta.put(“timestamp”, System.currentTimeMillis());

JSONObject data = new JSONObject();

data.put(“id”, 123);

data.put(“name”, “one-two-three”);

data.put(“desc”, “this is a number list”);

JSONObject json = new JSONObject();

json.put(“meta”, meta);

json.put(“data”, data);

json.put(“aaa”, “aaaaaa”);

System.out.println(json.toJSONString());

String xml = JsonXmlUtil.json2xml(json.toJSONString());

System.out.println(xml);

String jsonStr = JsonXmlUtil.xml2json(xml);

System.out.println(jsonStr);

}

}