如何将JSON反序列化为平面,类似Map的结构？

您可以执行此操作来遍历树并跟踪您有多深,以找出点符号属性名称:

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.databind.node.ValueNode;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import org.junit.Test;

public class FlattenJson {
  String json = "{\n" +
      "   \"Port\":\n" +
      "   {\n" +
      "       \"@alias\": \"defaultHttp\",\n" +
      "       \"Enabled\": \"true\",\n" +
      "       \"Number\": \"10092\",\n" +
      "       \"Protocol\": \"http\",\n" +
      "       \"KeepAliveTimeout\": \"20000\",\n" +
      "       \"ThreadPool\":\n" +
      "       {\n" +
      "           \"@enabled\": \"false\",\n" +
      "           \"Max\": \"150\",\n" +
      "           \"ThreadPriority\": \"5\"\n" +
      "       },\n" +
      "       \"ExtendedProperties\":\n" +
      "       {\n" +
      "           \"Property\":\n" +
      "           [                         \n" +
      "               {\n" +
      "                   \"@name\": \"connectionTimeout\",\n" +
      "                   \"$\": \"20000\"\n" +
      "               }\n" +
      "           ]\n" +
      "       }\n" +
      "   }\n" +
      "}";

  @Test
  public void testCreatingKeyValues() {
    Map<String, String> map = new HashMap<String, String>();
    try {
      addKeys("", new ObjectMapper().readTree(json), map);
    } catch (IOException e) {
      e.printStackTrace();
    }
    System.out.println(map);
  }

  private void addKeys(String currentPath, JsonNode jsonNode, Map<String, String> map) {
    if (jsonNode.isObject()) {
      ObjectNode objectNode = (ObjectNode) jsonNode;
      Iterator<Map.Entry<String, JsonNode>> iter = objectNode.fields();
      String pathPrefix = currentPath.isEmpty() ? "" : currentPath + ".";

      while (iter.hasNext()) {
        Map.Entry<String, JsonNode> entry = iter.next();
        addKeys(pathPrefix + entry.getKey(), entry.getValue(), map);
      }
    } else if (jsonNode.isArray()) {
      ArrayNode arrayNode = (ArrayNode) jsonNode;
      for (int i = 0; i < arrayNode.size(); i++) {
        addKeys(currentPath + "[" + i + "]", arrayNode.get(i), map);
      }
    } else if (jsonNode.isValueNode()) {
      ValueNode valueNode = (ValueNode) jsonNode;
      map.put(currentPath, valueNode.asText());
    }
  }
}

它产生以下地图:

Port.ThreadPool.Max=150, 
Port.ThreadPool.@enabled=false, 
Port.Number=10092, 
Port.ExtendedProperties.Property[0].@name=connectionTimeout, 
Port.ThreadPool.ThreadPriority=5, 
Port.Protocol=http, 
Port.KeepAliveTimeout=20000, 
Port.ExtendedProperties.Property[0].$=20000, 
Port.@alias=defaultHttp, 
Port.Enabled=true

它应该很容易剥离@并$在属性名称中,尽管你可能最终会在键名中发生冲突,因为你说JSON是任意的.

如何使用json-flattener.https://github.com/wnameless/json-flattener

顺便说一下,我是这个lib的作者.

String flattenedJson = JsonFlattener.flatten(yourJson);
Map<String, Object> flattenedJsonMap = JsonFlattener.flattenAsMap(yourJson);

// Result:
{
    "Port.@alias":"defaultHttp",
    "Port.Enabled":"true",
    "Port.Number":"10092",
    "Port.Protocol":"http",
    "Port.KeepAliveTimeout":"20000",
    "Port.ThreadPool.@enabled":"false",
    "Port.ThreadPool.Max":"150",
    "Port.ThreadPool.ThreadPriority":"5",
    "Port.ExtendedProperties.Property[0].@name":"connectionTimeout",
    "Port.ExtendedProperties.Property[0].$":"20000"
}

那个怎么样:

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import com.google.gson.Gson;

/**
 * NOT FOR CONCURENT USE
*/
@SuppressWarnings("unchecked")
public class JsonParser{

Gson gson=new Gson();
Map<String, String> flatmap = new HashMap<String, String>();

public Map<String, String> parse(String value) {        
    iterableCrawl("", null, (gson.fromJson(value, flatmap.getClass())).entrySet());     
    return flatmap; 
}

private <T> void iterableCrawl(String prefix, String suffix, Iterable<T> iterable) {
    int key = 0;
    for (T t : iterable) {
        if (suffix!=null)
            crawl(t, prefix+(key++)+suffix);
        else
            crawl(((Entry<String, Object>) t).getValue(), prefix+((Entry<String, Object>) t).getKey());
    }
}

private void crawl(Object object, String key) {
    if (object instanceof ArrayList)
        iterableCrawl(key+"[", "]", (ArrayList<Object>)object);
    else if (object instanceof Map)
        iterableCrawl(key+".", null, ((Map<String, Object>)object).entrySet());
    else
        flatmap.put(key, object.toString());
}
}