我的Android进阶之旅------>android如何将List请求参数列表转换为json格式

本文同步发表在简书，链接：http://www.jianshu.com/p/395a4c8b05b9

前言

由于接收原来的老项目并进行维护，之前的http请求是使用Apache Jakarta Common下的子项目HttpClient，因此使用了 List<NameValuePair> 方式来创建参数队列，然后通过一个字符串处理的工具类，生成的post请求体格式大致如：

a=b&c=d&e=f

但是由于服务器api变更，需要将请求体的格式变成json格式，因此上面的请求参数要变成：

{"a":"b","c":"d","e":"f"}

但是如果将List<NameValuePair>直接通过Jackson或者Gson等第三方工具的转json的开源类库去转换为json格式的话，转出来的json格式如：

[{"name":"a","value":"b"},{"name":"c","value":"d"},{"name":"e","value":"f"}]

如下面代码所示：

public class RequestParams {
        /**请求地址*/
        public String url;
        /**请求参数集合*/
        public List<NameValuePair> params;
    }

    /**
     * 帐号登录
     *
     * @param userName 账号名
     * @param password 密码
     * @param days     记住密码天数：days>0定期超时；days=-2永不失效；
     *                 days=-1永久记住密码（30天没有操作则失效）
     * @param deviceId 账户在设备上的唯一标识符（机器码或mac地址）
     * @param appId    应用id
     * @return
     */
    public static RequestParams loginParams(String userName, String password, int days, String deviceId, int appId) {
        RequestParams params = new RequestParams();
        params.url = LOGIN_URI;
        params.params = new ArrayList<NameValuePair>();
        params.params.add(new BasicNameValuePair("userName", userName));
        params.params.add(new BasicNameValuePair("password", password));
        params.params.add(new BasicNameValuePair("days", String.valueOf(days)));
        params.params.add(new BasicNameValuePair("deviceId", deviceId));
        params.params.add(new BasicNameValuePair("appId", String.valueOf(appId)));
        params = addcommonParams(params, LOGIN_URI, appId);
        return params;
    }

在请求的时候，将List<NameValuePair> params取出来，然后使用JSONUtil工具类转换成json格式，代码如下所示：

String request=JSONUtil.toJSON(requestParams.params);

其中换成json格式的工具类JSONUtil,该工具类使用了jackjson的第三方json解析库，代码如下所示：

    import android.util.Log;

    import com.fasterxml.jackson.annotation.JsonInclude.Include;
    import com.fasterxml.jackson.core.JsonGenerationException;
    import com.fasterxml.jackson.core.JsonParseException;
    import com.fasterxml.jackson.databind.DeserializationFeature;
    import com.fasterxml.jackson.databind.JsonMappingException;
    import com.fasterxml.jackson.databind.ObjectMapper;
    import com.fasterxml.jackson.databind.SerializationFeature;

    import org.json.JSONException;
    import org.json.JSONObject;

    import java.io.IOException;
    import java.io.StringWriter;
    import java.io.Writer;

    /**
     * JSON转换工具类
     *
     * @author  OuyangPeng
     * @version [1.0.0.0, 2016-3-23]
     */
    public class JSONUtil {

        private static String TAG = SSOJSONUtil.class.getName();

        private static ObjectMapper mapper = new ObjectMapper();

        static {
            //对于为null的字段不进行序列化
            mapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);
            //对于未知属性不进行反序列化
            mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
            //无论对象中的值只有不为null的才进行序列化
            mapper.setSerializationInclusion(Include.NON_NULL);
        }

        /**
         * 把对象转化成json字符串
         *
         * @param obj
         * @return
         */
        public static String toJSON(Object obj) {
            if (obj == null) {
                return null;
            }

            Writer write = new StringWriter();
            try {
                mapper.writeValue(write, obj);
            } catch (JsonGenerationException e) {
                Log.e(TAG, e.toString() + obj);
            } catch (JsonMappingException e) {
                Log.e(TAG, e.toString() + obj);
            } catch (IOException e) {
                Log.e(TAG, e.toString() + obj);
            }
            return write.toString();
        }

        /**
         * JSON字符串转成对象
         *
         * @param jsonStr
         * @param classType
         * @return
         */
        public static <T> T fromJSON(String jsonStr, Class<T> classType) {
            if (isEmptyOrNull(jsonStr)) {
                return null;
            }

            T t = null;
            try {
                t = mapper.readValue(jsonStr.getBytes("utf-8"), classType);
            } catch (JsonParseException e) {
                Log.e(TAG, e.toString() + ", jsonStr:" + jsonStr + ", classType:" + classType.getName());
            } catch (JsonMappingException e) {
                Log.e(TAG, e.toString() + ", jsonStr:" + jsonStr + ", classType:" + classType.getName());
            } catch (IOException e) {
                Log.e(TAG, e.toString() + ", jsonStr:" + jsonStr + ", classType:" + classType.getName());
            }
            return t;
        }

        /**
         * JSON字符串转化成集合
         *
         * @param jsonStr
         * @return
         */
        public static <T> T toCollection(String jsonStr, Class<?> collectionClass, Class<?>... elementClasses) {
            if (isEmptyOrNull(jsonStr)) {
                return null;
            }

            T t = null;
            try {
                t = mapper.readValue(jsonStr.getBytes("utf-8")
                        , mapper.getTypeFactory().constructParametricType(collectionClass, elementClasses));
            } catch (JsonParseException e) {
                e.printStackTrace();
                Log.e(TAG, e.toString() + ", jsonStr:" + jsonStr);
            } catch (JsonMappingException e) {
                e.printStackTrace();
                Log.e(TAG, e.toString() + ", jsonStr:" + jsonStr);
            } catch (IOException e) {
                Log.e(TAG, e.toString() + ", jsonStr:" + jsonStr);
            }
            return t;
        }

        public static Object get(String jsonStr, String key) {
            Object obj = null;
            try {
                JSONObject jsonObj = new JSONObject(jsonStr);
                obj = jsonObj.get(key);
            } catch (JSONException e) {
                e.printStackTrace();
            }
            return obj;
        }

        /**
         * 判断字符串是否为null或者""
         */
        public static boolean isEmptyOrNull(String content) {
            if (content == null || content.equals("")) {
                return true;
            }
            return false;
        }
    }

使用上面的代码将List<NameValuePair> params请求参数集合转换为json后，（不标准）格式如下所示：

[{"name":"userName","value":"13911002200"},{"name":"password","value":"123456"},
{"name":"days","value":"-1"},{"name":"deviceId","value":"02:00:00:00:00:00"},
{"name":"appId","value":"11"},{"name":"mac","value":"02:00:00:00:00:00"},
{"name":"timestamp","value":"2016-03-26 10:24:35"},
{"name":"sign","value":"b2873caa5735d16535ff827ee2701cd1"}]

好吧，这样的格式完全不是标准的json格式，服务器那边需要的（标准）json格式是：

{"deviceId":"02:00:00:00:00:00","password":"123456","days":"-1","sign":"b2873caa5735d16535ff827ee2701cd1",
"mac":"02:00:00:00:00:00","timestamp":"2016-03-26 10:24:35","appId":"11","userName":"13911002200"}

另外一个请求参数队列转后的json格式如下，（不标准）：

[{"name":"accountId","value":"2384403"},{"name":"password","value":"123456"},
{"name":"ticket","value":"{\"accountId\":\"2384403\",\"appId\":\"11\",
\"loginName\":\"1302200\",\"userName\":\"U12384403\",\"email\":\"\",\"mobilePhone\":\"1302200\",
\"timestamp\":\"2016-03-26\",\"maxAge\":-1,\"ip\":\"\",\"sign\":\"4109c59eff52a924e74be3623ecab27d\",
\"deviceId\":\"02:00:00:00:00:00\"}"},
{"name":"appId","value":"11"},{"name":"mac","value":"02:00:00:00:00:00"},
{"name":"timestamp","value":"2016-03-26 10:26:01"},
{"name":"sign","value":"22070f51197c15d256764a2de499ef85"}]

服务器那边需要的另外一个请求参数队列转后的（标准）json格式如下所示：

{"timestamp":"2016-03-26 10:26:01","password":"123456","appId":"11",
"ticket":"{\"accountId\":\"2384403\",\"appId\":\"11\",\"loginName\":\"1302200\",
\"userName\":\"U12384403\",\"email\":\"\",\"mobilePhone\":\"1302200\",\"timestamp\":\"2016-03-26\",
\"maxAge\":-1,\"ip\":\"\",\"sign\":\"4109c59eff52a924e74be3623ecab27d\",
\"deviceId\":\"02:00:00:00:00:00\"}","sign":"22070f51197c15d256764a2de499ef85",
"accountId":"2384403","mac":"02:00:00:00:00:00"}

好的，现在来说一说解决方法：

step1:将List<NameValuePair> params进行遍历然后丢在同一个Map集合中去

step2:使用JONUtil对Map集合进行转换成json格式字符串

代码如下所示：

/*** 将请求参数转换为json格式*/
Map map=new HashMap();
for (int i=0;i<requestParams.params.size();i++){
    NameValuePair nameValuePair=requestParams.params.get(i);
    map.put(nameValuePair.getName(),nameValuePair.getValue());
}
String request=SSOJSONUtil.toJSON(requestParams.params);
String jsonRequest=SSOJSONUtil.toJSON(map);
LogUtil.d(TAG, "发送给服务器的内容为:加密前的data:：" + request);
LogUtil.d(TAG, "发送给服务器的内容为:加密前的 json data:：" + jsonRequest);

打印出来的日志如下所示：

发送给服务器的内容为:加密前的data:：[{"name":"userName","value":"13011002200"},
{"name":"password","value":"123456"},{"name":"days","value":"-1"},
{"name":"deviceId","value":"02:00:00:00:00:00"},{"name":"appId","value":"11"},
{"name":"mac","value":"02:00:00:00:00:00"},{"name":"timestamp","value":"2016-03-26 10:24:35"},
{"name":"sign","value":"b2873caa5735d16535ff827ee2701cd1"}]

发送给服务器的内容为:加密前的 json data:：{"deviceId":"02:00:00:00:00:00",
"password":"123456","days":"-1","sign":"b2873caa5735d16535ff827ee2701cd1",
"mac":"02:00:00:00:00:00","timestamp":"2016-03-26 10:24:35","appId":"11","userName":"13011002200"}

发送给服务器的内容为:加密前的data:：[{"name":"accountId","value":"2384403"},
{"name":"password","value":"123456"},
{"name":"ticket","value":"{\"accountId\":\"2384403\",\"appId\":\"11\",\"loginName\":\"130***2200\",
\"userName\":\"U12384403\",\"email\":\"\",\"mobilePhone\":\"130***2200\",\"timestamp\":\"2016-03-26\",
\"maxAge\":-1,\"ip\":\"\",\"sign\":\"4109c59eff52a924e74be3623ecab27d\",
\"deviceId\":\"02:00:00:00:00:00\"}"},{"name":"appId","value":"11"},
{"name":"mac","value":"02:00:00:00:00:00"},
{"name":"timestamp","value":"2016-03-26 10:26:01"},
{"name":"sign","value":"22070f51197c15d256764a2de499ef85"}]

发送给服务器的内容为:加密前的 json data:：{"timestamp":"2016-03-26 10:26:01",
"password":"123456","appId":"11",
"ticket":"{\"accountId\":\"2384403\",\"appId\":\"11\",\"loginName\":\"130***2200\",
\"userName\":\"U12384403\",\"email\":\"\",\"mobilePhone\":\"130***2200\",
\"timestamp\":\"2016-03-26\",\"maxAge\":-1,\"ip\":\"\",
\"sign\":\"4109c59eff52a924e74be3623ecab27d\",\"deviceId\":\"02:00:00:00:00:00\"}",
"sign":"22070f51197c15d256764a2de499ef85","accountId":"2384403","mac":"02:00:00:00:00:00"}

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  作者：欧阳鹏  欢迎转载，与人分享是进步的源泉！

  转载请保留原文地址：http://blog.csdn.net/ouyang_peng

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