json将HOCON字符串转换为Java对象

Question

我的一个Web服务返回以下Java字符串：

[
  {
    id=5d93532e77490b00013d8862, 
    app=null,
    manufacturer=pearsonEducation, 
    bookUid=bookIsbn, 
    model=2019,
    firmware=[1.0], 
    bookName=devotional, 
    accountLinking=mandatory
  }
]

对于上面的字符串，我有一个等价的Java对象。我想将上面的java字符串类型转换成java对象

我无法键入cast，因为它是字符串，而不是对象。因此，我试图将Java字符串转换为JSON字符串，然后我可以将该字符串写入Java对象，但没有运气得到invalid character "="异常

Can you change the web service to return JSON?

那是不可能的。他们没有改变合同。如果他们返回JSON，这将非常容易

Answer 1

在我看来，我们将解析过程分为两步

1. 将输出数据格式化为JSON
2. 通过JSON UTIL解析文本

在这个演示代码中，我选择regex作为格式化方法，选择fastjson作为JSON工具。你可以选择杰克逊或格森。此外，我删除了[{}，您可以将其放回，然后将其解析到数组中

import com.alibaba.fastjson.JSON;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class SerializedObject {
    private String id;
    private String app;

    static Pattern compile = Pattern.compile("([a-zA-Z0-9.]+)");
    public static void main(String[] args) {
        String str =
                "  {\n" +
                "    id=5d93532e77490b00013d8862, \n" +
                "    app=null,\n" +
                "    manufacturer=pearsonEducation, \n" +
                "    bookUid=bookIsbn, \n" +
                "    model=2019,\n" +
                "    firmware=[1.0], \n" +
                "    bookName=devotional, \n" +
                "    accountLinking=mandatory\n" +
                "  }\n";
        String s1 = str.replaceAll("=", ":");
        StringBuffer sb = new StringBuffer();
        Matcher matcher = compile.matcher(s1);
        while (matcher.find()) {
            matcher.appendReplacement(sb, "\"" + matcher.group(1) + "\"");
        }
        matcher.appendTail(sb);
        System.out.println(sb.toString());

        SerializedObject serializedObject = JSON.parseObject(sb.toString(), SerializedObject.class);
        System.out.println(serializedObject);
    }
}

Answer 2

嗯，这肯定不是这里给出的最佳答案，但这是可能的，至少

通过像这样的小步操作String，以获得可以处理的Map<String, String>。看这个例子，它非常基本：

public static void main(String[] args) {
    String data = "[\r\n" 
            + "  {\r\n"
            + "    id=5d93532e77490b00013d8862, \r\n"
            + "    app=null,\r\n"
            + "    manufacturer=pearsonEducation, \r\n"
            + "    bookUid=bookIsbn, \r\n"
            + "    model=2019,\r\n"
            + "    firmware=[1.0], \r\n"
            + "    bookName=devotional, \r\n"
            + "    accountLinking=mandatory\r\n"
            + "  }\r\n"
            + "]";

    // manipulate the String in order to have
    String[] splitData = data
            // no leading and trailing [ ] - cut the first and last char
            .substring(1, data.length() - 1)
            // no linebreaks
            .replace("\n", "")
            // no windows linebreaks
            .replace("\r", "")
            // no opening curly brackets
            .replace("{", "")
            // and no closing curly brackets.
            .replace("}", "")
            // Then split it by comma
            .split(",");

    // create a map to store the keys and values
    Map<String, String> dataMap = new HashMap<>();

    // iterate the key-value pairs connected with '='
    for (String s : splitData) {
        // split them by the equality symbol
        String[] keyVal = s.trim().split("=");
        // then take the key
        String key = keyVal[0];
        // and the value
        String val = keyVal[1];
        // and store them in the map ——> could be done directly, of course
        dataMap.put(key, val);
    }

    // print the map content
    dataMap.forEach((key, value) -> System.out.println(key + " ——> " + value));
}

Please note that I just copied your example String which may have caused the line breaks and I think it is not smart to just replace() all square brackets because the value firmware seems to include those as content.

Answer 3

web服务返回的格式有自己的名称HOCON。（您可以阅读更多关于它的信息here）

您不需要自定义解析器。不要试图重新发明轮子。 改用现有的

---

将此maven依赖项添加到项目中：

<dependency>
    <groupId>com.typesafe</groupId>
    <artifactId>config</artifactId>
    <version>1.3.0</version>
</dependency>

然后按如下方式解析响应：

Config config = ConfigFactory.parseString(text);

String id = config.getString("id");
Long model = config.getLong("model");

---

还有一个选项可以将整个字符串解析为POJO：

MyResponsePojo response = ConfigBeanFactory.create(config, MyResponsePojo.class);

不幸的是，这个解析器不允许null值。因此，您需要处理类型为com.typesafe.config.ConfigException.Null的异常

---

另一个选项是将HOCON字符串转换为JSON：

String hoconString = "...";
String jsonString = ConfigFactory.parseString(hoconString)
                                 .root()
                                 .render(ConfigRenderOptions.concise());

然后可以使用任何JSON到POJO映射器