Java在Map转Json字符串时出现"\"转义字符的解决办法
作者:一个胖子IT男
项目中出现了这样一个问题,当一个Map被转成Json字符串后,由于业务需求,会将Map转为JsonObject,添加元素后,又转成Json字符串,最后再被包装到另一个Map里,被转成Json字符串发送给APP端,这个时候APP端反应结果中带有“\”转义字符,无法解析。
简化一下问题
当一个Map被转成Json字符串后,被添加到另一个Map中,如果这个新的Map需要转成Json字符串格式,那么转化后,内部的这个Map转成的Json字符串,都会被加上“\”转义字符。
简单的模拟一下
public static void main(String[] args) { HashMap<String, Object> param = new HashMap<>(); param.put("userId", 66666); param.put("username", "XXXX"); HashMap<String, String> pushMap = new HashMap<>(); pushMap.put("testKey01", "value01"); pushMap.put("testKey02", "value02"); param.put("pushJson", JSON.toJSONString(pushMap)); String pushJson = JSON.toJSONString(param); System.out.println(pushJson); }
格式化一下结果:
{
"pushJson":
"{\"testKey01\":\"value01\",\"testKey02\":\"value02\"}",
"userId":66666,
"username":"XXXX"
}
延伸测试一下,如果用JSONObject转Json字符串会不会有问题:
public static void main(String[] args) { HashMap<String, Object> param = new HashMap<>(); param.put("userId", 66666); param.put("username", "XXXX"); // HashMap<String, String> pushMap = new HashMap<>(); // pushMap.put("testKey01", "value01"); // pushMap.put("testKey02", "value02"); JSONObject pushObject = new JSONObject(); pushObject.put("testKey01", "value01"); pushObject.put("testKey02", "value02"); param.put("pushJson", pushObject.toJSONString()); String pushJson = JSON.toJSONString(param); System.out.println(pushJson); }
格式化一下结果:
{
"pushJson":
"{\"testKey01\":\"value01\",\"testKey02\":\"value02\"}",
"userId":66666,
"username":"XXXX"
}
用原本的Map和JSONObject:
public static void main(String[] args) { HashMap<String, Object> param = new HashMap<>(); param.put("userId", 66666); param.put("username", "XXXX"); HashMap<String, String> pushMap = new HashMap<>(); pushMap.put("testKey01", "value01"); pushMap.put("testKey02", "value02"); JSONObject pushObject = new JSONObject(); pushObject.put("testKey01", "value01"); pushObject.put("testKey02", "value02"); param.put("pushJson", pushMap); String pushJson1 = JSON.toJSONString(param); System.out.println(pushJson1); param.put("pushJson", pushObject); String pushJson2 = JSON.toJSONString(param); System.out.println(pushJson2); }
结果:
{"pushJson":{"testKey01":"value01","testKey02":"value02"},"userId":66666,"username":"XXXX"}
{"pushJson":{"testKey01":"value01","testKey02":"value02"},"userId":66666,"username":"XXXX"}
这样就不带转义字符了
而项目中,我是采用将JSON字符串转回Map,然后添加到新的Map中,再转成JSON字符串的方式解决这个问题的:
HashMap<String, Object> pushApp = new HashMap<>(); pushApp.put("userId", userList); pushApp.put("pushType", pushType); pushApp.put("pushJson", JSON.parseObject(message, HashMap.class)); String pushJson = JSON.toJSONString(pushApp);
当然上面带“\”转义字符的结果也是有办法解析的:
public static void main(String[] args) { HashMap<String, Object> param = new HashMap<>(); param.put("userId", 66666); param.put("username", "XXXX"); HashMap<String, String> pushMap = new HashMap<>(); pushMap.put("testKey01", "value01"); pushMap.put("testKey02", "value02"); param.put("pushJson", JSON.toJSONString(pushMap)); String pushJson = JSON.toJSONString(param); System.out.println(pushJson); JSONObject jsonObject = JSONObject.parseObject(pushJson); JSONObject jsonData = jsonObject.getJSONObject("pushJson"); System.out.println("pushJson: " + jsonData); String value1 = jsonData.getString("testKey01"); System.out.println("key: testKey01 value: " + value1); }
结果:
{"pushJson":"{\"testKey01\":\"value01\",\"testKey02\":\"value02\"}","userId":66666,"username":"XXXX"}
pushJson: {"testKey01":"value01","testKey02":"value02"}
key: testKey01 value: value01
2019-09-12
HashMap jsonMap = JSON.parseObject(pushJson,HashMap.class); String resultJson = String.valueOf(jsonMap.get("pushJson")); System.out.println(resultJson);
反解析的时候,还是可以正常解析出来,不需要转成jsonObject也可以
{"pushJson":"{\"testKey01\":\"value01\",\"testKey02\":\"value02\"}","userId":66666,"username":"XXXX"}
{"testKey01":"value01","testKey02":"value02"}
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