Java中将xml文件转化为json遇到特殊字符会报错！-原创手记-慕课网

前言：
我们在项目开发中，有时候调用别人提供的接口，接收到的数据是xml，这时候为了方便后续开发中的使用，需要解析xml并把数据转化成json，今天这篇文章就讲解下如何把xml转化成json，并在这个过程中容易出现的问题。
正文：
一、测试项目的搭建
1.需要引入的pom依赖

<dependency>
	<groupId>com.google.code.gson</groupId>
	<artifactId>gson</artifactId>
	<version>2.7</version>
</dependency>
<dependency>
	<groupId>cn.hutool</groupId>
	<artifactId>hutool-all</artifactId>
	<version>4.0.9</version>
</dependency>

2.xml映射的对象

@Data
    @AllArgsConstructor
    @NoArgsConstructor
   public class Programmer{
        private String name;
        private Integer age;
        private String sex;
        private String img;
    }

3.转化的工具类

public class Xml2Json {
public static  <T> T convertToObject(String xml, Class<T> cla){
        JSONObject object = XML.toJSONObject(xml);
        String jsonData = object.toString();
        System.err.println(jsonData);
        //截取字符串
        String jsonObject = jsonData.substring(jsonData.indexOf(":")+1, jsonData.length()-1);
        //将json格式的字符串转换成CertApplyRequest格式
        Gson gson = new Gson();
        T request = gson.fromJson(jsonObject, cla);
        return request;
    }

二、复现问题
1.测试代码

  public static void main(String[] args){
        String s="<student name=\"zhangsan\">\n" +
                "   <sex>man</sex>\n" +
                "    <age>18</age>\n" +
                "\t<img>https://image.baidu.com/search/detail?ct=503316480&z=0&tn=baiduimagedetail&ipn=d&cl=2&cm=1&sc=0&lm=-1&ie=gb18030&pn=3&rn=1&di=99220&ln=30&word=%C5%ED%D3%DA%EA%CC&os=296869242,2380769407&cs=366539099,4208170291&objurl=http%3A%2F%2Fhbimg.b0.upaiyun.com%2Fd8241f63c93bb0f35d6f8557cff86cb524a9b6f71178f5-3NGIpU_fw658&bdtype=0&simid=3446695705,94736452&pi=0&adpicid=0&timingneed=0&spn=0&is=0,0&fr=ala&ala=1" +
                "&alatpl=adress&pos=1&oriquery=%E5%BD%AD%E4%BA%8E%E6%99%8F&hs=2&xthttps=111111</img>\n" +
                "</student>\n";
        System.out.println(s);
        Programmer programmer = Xml2Json.convertToObject(s, Programmer.class);
        System.out.println(programmer.toString());
    }

2.运行结果：报错啦！

<student name="zhangsan">
   <sex>man</sex>
    <age>18</age>
	<img>https://image.baidu.com/search/detail?ct=503316480&z=0&tn=baiduimagedetail&ipn=d&cl=2&cm=1&sc=0&lm=-1&ie=gb18030&pn=3&rn=1&di=99220&ln=30&word=%C5%ED%D3%DA%EA%CC&os=296869242,2380769407&cs=366539099,4208170291&objurl=http%3A%2F%2Fhbimg.b0.upaiyun.com%2Fd8241f63c93bb0f35d6f8557cff86cb524a9b6f71178f5-3NGIpU_fw658&bdtype=0&simid=3446695705,94736452&pi=0&adpicid=0&timingneed=0&spn=0&is=0,0&fr=ala&ala=1&alatpl=adress&pos=1&oriquery=%E5%BD%AD%E4%BA%8E%E6%99%8F&hs=2&xthttps=111111</img>
</student>

Exception in thread "main" cn.hutool.json.JSONException: Missing ';' in XML entity: &z at 121 [character 59 line 4]
	at cn.hutool.json.JSONTokener.syntaxError(JSONTokener.java:373)
	at cn.hutool.json.XMLTokener.nextEntity(XMLTokener.java:107)
	at cn.hutool.json.XMLTokener.nextContent(XMLTokener.java:83)
	at cn.hutool.json.XML.parse(XML.java:171)
	at cn.hutool.json.XML.parse(XML.java:185)
	at cn.hutool.json.XML.toJSONObject(XML.java:232)
	at cn.hutool.json.XML.toJSONObject(XML.java:214)
	at com.model.Xml2Json.convertToObject(Xml2Json.java:15)
	at com.model.Xml2Json.main(Xml2Json.java:46)

Process finished with exit code 1

3.分析结果
一般出现上面的异常，基本都是xml里的格式或者有特殊字符才报错的，所以我们可以看下我们的xml里的参数是否有特殊字符。可以看到img标签里的图片地址有特殊字符&，所以这时候我们只要把&进行转义，就可以啦。
三、解决问题
1.修改后的测试代码：

public static void main(String[] args){
        String s="<student name=\"zhangsan\">\n" +
                "   <sex>man</sex>\n" +
                "    <age>18</age>\n" +
                "\t<img>https://image.baidu.com/search/detail?ct=503316480&z=0&tn=baiduimagedetail&ipn=d&cl=2&cm=1&sc=0&lm=-1&ie=gb18030&pn=3&rn=1&di=99220&ln=30&word=%C5%ED%D3%DA%EA%CC&os=296869242,2380769407&cs=366539099,4208170291&objurl=http%3A%2F%2Fhbimg.b0.upaiyun.com%2Fd8241f63c93bb0f35d6f8557cff86cb524a9b6f71178f5-3NGIpU_fw658&bdtype=0&simid=3446695705,94736452&pi=0&adpicid=0&timingneed=0&spn=0&is=0,0&fr=ala&ala=1" +
                "&alatpl=adress&pos=1&oriquery=%E5%BD%AD%E4%BA%8E%E6%99%8F&hs=2&xthttps=111111</img>\n" +
                "</student>\n";
        String s1 = s.replaceAll("&", "&amp;");
        System.out.println(s);
        System.out.println(s1);
        Programmer programmer = Xml2Json.convertToObject(s1, Programmer.class);
        System.out.println(programmer.toString());
    }

2.运行结果：xml转化json成功。

<student name="zhangsan">
   <sex>man</sex>
    <age>18</age>
	<img>https://image.baidu.com/search/detail?ct=503316480&z=0&tn=baiduimagedetail&ipn=d&cl=2&cm=1&sc=0&lm=-1&ie=gb18030&pn=3&rn=1&di=99220&ln=30&word=%C5%ED%D3%DA%EA%CC&os=296869242,2380769407&cs=366539099,4208170291&objurl=http%3A%2F%2Fhbimg.b0.upaiyun.com%2Fd8241f63c93bb0f35d6f8557cff86cb524a9b6f71178f5-3NGIpU_fw658&bdtype=0&simid=3446695705,94736452&pi=0&adpicid=0&timingneed=0&spn=0&is=0,0&fr=ala&ala=1&alatpl=adress&pos=1&oriquery=%E5%BD%AD%E4%BA%8E%E6%99%8F&hs=2&xthttps=111111</img>
</student>

<student name="zhangsan">
   <sex>man</sex>
    <age>18</age>
	<img>https://image.baidu.com/search/detail?ct=503316480&amp;z=0&amp;tn=baiduimagedetail&amp;ipn=d&amp;cl=2&amp;cm=1&amp;sc=0&amp;lm=-1&amp;ie=gb18030&amp;pn=3&amp;rn=1&amp;di=99220&amp;ln=30&amp;word=%C5%ED%D3%DA%EA%CC&amp;os=296869242,2380769407&amp;cs=366539099,4208170291&amp;objurl=http%3A%2F%2Fhbimg.b0.upaiyun.com%2Fd8241f63c93bb0f35d6f8557cff86cb524a9b6f71178f5-3NGIpU_fw658&amp;bdtype=0&amp;simid=3446695705,94736452&amp;pi=0&amp;adpicid=0&amp;timingneed=0&amp;spn=0&amp;is=0,0&amp;fr=ala&amp;ala=1&amp;alatpl=adress&amp;pos=1&amp;oriquery=%E5%BD%AD%E4%BA%8E%E6%99%8F&amp;hs=2&amp;xthttps=111111</img>
</student>

{"student":{"img":"https://image.baidu.com/search/detail?ct=503316480&z=0&tn=baiduimagedetail&ipn=d&cl=2&cm=1&sc=0&lm=-1&ie=gb18030&pn=3&rn=1&di=99220&ln=30&word=%C5%ED%D3%DA%EA%CC&os=296869242,2380769407&cs=366539099,4208170291&objurl=http%3A%2F%2Fhbimg.b0.upaiyun.com%2Fd8241f63c93bb0f35d6f8557cff86cb524a9b6f71178f5-3NGIpU_fw658&bdtype=0&simid=3446695705,94736452&pi=0&adpicid=0&timingneed=0&spn=0&is=0,0&fr=ala&ala=1&alatpl=adress&pos=1&oriquery=%E5%BD%AD%E4%BA%8E%E6%99%8F&hs=2&xthttps=111111","sex":"man","name":"zhangsan","age":18}}
Xml2Json.Programmer(name=zhangsan, age=18, sex=man, img=https://image.baidu.com/search/detail?ct=503316480&z=0&tn=baiduimagedetail&ipn=d&cl=2&cm=1&sc=0&lm=-1&ie=gb18030&pn=3&rn=1&di=99220&ln=30&word=%C5%ED%D3%DA%EA%CC&os=296869242,2380769407&cs=366539099,4208170291&objurl=http%3A%2F%2Fhbimg.b0.upaiyun.com%2Fd8241f63c93bb0f35d6f8557cff86cb524a9b6f71178f5-3NGIpU_fw658&bdtype=0&simid=3446695705,94736452&pi=0&adpicid=0&timingneed=0&spn=0&is=0,0&fr=ala&ala=1&alatpl=adress&pos=1&oriquery=%E5%BD%AD%E4%BA%8E%E6%99%8F&hs=2&xthttps=111111)

总结：
xml转化josn报错的时候基本上都是xml的格式不正确或者是数据里有特殊字符，对了xml里的标签头不用转义，转义后反而会报错，原因在源码里。
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