json字符串轉成java的map與list複合對象的解決方法

開發時需要將json字符串轉成java的map和list，找了半天竟然沒有一個現成的的包支持這種功能！不可思議，苦苦在stackoverflow上求醫問藥，終於找到jackson的一個特性，可以生成json的節點樹，這才終於解決了這個頭疼的問題。

代碼引用了jackson2.7.3的兩個包：

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.7.3</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.7.3</version>
        </dependency>

遞歸遍歷每個節點然後判斷節點的類型做轉換，代碼如下：

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.util.*;


/**
 * Created by fineTu on 2016/09/27.
 */
public class JsonUtil {



    public static Map<String,Object> parse(String jsonStr) throws IOException {
        Map<String,Object> resMap = new HashMap<String, Object>();
        JsonFactory factory = new JsonFactory();
        ObjectMapper mapper = new ObjectMapper(factory);
        JsonNode rootNode = mapper.readTree(jsonStr);


        resMap = parseNode2Obj(rootNode);
        return resMap;
    }


    private static Map<String,Object> parseNode2Obj(JsonNode jsonNode){
        Map<String,Object> resMap = new HashMap<String, Object>();
        if(jsonNode.isValueNode()){
            Object value = parseValue(jsonNode);
            resMap.put("",value);
            return resMap;
        }else if(jsonNode.isArray()){
            List<Object> list = new ArrayList<Object>();
            Iterator<JsonNode> it = jsonNode.iterator();
            while( it.hasNext()){
                Map<String,Object> child = parseNode2Obj(it.next());
                if (child.keySet().size() == 1 && child.keySet().contains("")){
                    list.add(child.get(""));
                }else{
                    list.add(child);
                }
            }
            resMap.put("",list);
            return resMap;
        }else {
            Iterator<Map.Entry<String,JsonNode>> it = jsonNode.fields();
            while( it.hasNext()){
                Map.Entry<String,JsonNode> entry = it.next();
                Map<String,Object> child = parseNode2Obj(entry.getValue());
                if (child.keySet().size() == 1 && child.keySet().contains("")){
                    resMap.put(entry.getKey(),child.get(""));
                }else{
                    resMap.put(entry.getKey(),child);
                }
            }
            return resMap;
        }
    }


    private static Object parseValue(JsonNode valueNode){
        if(valueNode.isTextual()){
            return valueNode.asText();
        }else if(valueNode.isInt()){
            return valueNode.asInt();
        }else if(valueNode.isBigInteger() || valueNode.isLong()){
            return valueNode.asLong();
        }else if(valueNode.isFloat() || valueNode.isDouble()){
            return valueNode.asDouble();
        }else if(valueNode.isBoolean()){
            return valueNode.asBoolean();
        }
        return valueNode.asText();
    }
    public static void main(String[] args){
        String jsonStr = "{\"a\":12,\"b\":\"foobar\",\"c\":[\"tom\",\"peter\",\"joe\"],\"d\":{\"da\":\"1123\",\"db\":456,\"dc\":[{\"name\":\"super man\",\"id\":1},{\"name\":\"bat man\",\"id\":2}]}}";
        try {
            Map<String,Object> resMap = JsonUtil.parse(jsonStr);
            System.out.println(resMap);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


}

代碼貢獻出來，節省你的時間

轉載請註明出處：http://blog.csdn.net/gklifg/article/details/52680854