json字符串转成java的map与list复合对象的解决方法

开发时需要将json字符串转成java的map和list，找了半天竟然没有一个现成的的包支持这种功能！不可思议，苦苦在stackoverflow上求医问药，终于找到jackson的一个特性，可以生成json的节点树，这才终于解决了这个头疼的问题。

代码引用了jackson2.7.3的两个包：

<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>

递归遍历每个节点然后判断节点的类型做转换，代码如下：

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();
}
}

}

代码贡献出来，节省你的时间

转载请注明出处：http://blog.csdn.net/gklifg/article/details/52680854