Java 将 Map<String, Object> 转换为 json
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Converting Map<String, Object> to json
提问by Razib
I have a map called responseObj
我有一个名为 responseObj 的地图
Map<String, object> responseObj = new HashMap<String, Object>();
I have added some value in the responseObj like this -
我在 responseObj 中添加了一些像这样的值 -
responseObj.put("canApprove", true); //1
responseObj.put("approvers", userList);
The userListis a list or users -
这userList是一个列表或用户 -
List<User> userList = new ArrayList<User>();
The user Object from the User class -
来自 User 类的用户对象 -
class User {
private int userId;
private int roleId;
}
Now I have some questions -
现在我有一些问题——
Is it possible to convert the
responseObjto a json so that"canApprove"and"approvers"become key of json (see the code snippent below) and how can I make it?{ "canApprove" : true, "approver": [ { "userId": 309, "roleId": 2009 }, { "userId": 3008, "roleId": 2009 },] }
If I convert it into a json and get the response from jsp can I able get the appropriate boolean in jsp where the
"canApprove"refers anObjectin theresponseObj?Can I persist the
"userId" and "roleId"to JSON fromUserClass?
是否有可能转换
responseObj成JSON，以便"canApprove"和"approvers"成为JSON的关键（见下面的代码snippent），我该怎么做呢？{ "canApprove" : true, "approver": [ { "userId": 309, "roleId": 2009 }, { "userId": 3008, "roleId": 2009 },] }
如果我把它转换成JSON，并从JSP的响应可以我能够获得在JSP中相应的布尔其中
"canApprove"是指的Object在responseObj？我可以
"userId" and "roleId"从UserClass持久化到 JSON吗？
采纳答案by ToYonos
Try this :
尝试这个 ：
public static class User
{
public User(int userId, int roleId)
{
this.userId = userId;
this.roleId = roleId;
}
private int userId;
private int roleId;
public int getUserId()
{
return userId;
}
public int getRoleId()
{
return roleId;
}
public void setUserId(int userId)
{
this.userId = userId;
}
public void setRoleId(int roleId)
{
this.roleId = roleId;
}
}
Test :
测试 ：
Map<String, Object> responseObj = new HashMap<String, Object>();
List<User> userList = new ArrayList<User>();
userList.add(new User(1, 1));
userList.add(new User(2, 2));
responseObj.put("canApprove", true); //1
responseObj.put("approvers", userList);
System.out.println(new JSONObject(responseObj));
Prints :
印刷 ：
{"approvers":[{"userId":1,"roleId":1},{"userId":2,"roleId":2}],"canApprove":true}
回答by Attila Neparáczki
new com.google.gson.Gson().toJson(responseObj);
回答by Safrain
You can use some json serialization libraries to do this work for you, like fastjsonor gson
您可以使用一些 json 序列化库来为您完成这项工作，例如fastjson或gson
1.Import the dependency jars into your project, add a <dependency>node into you pom.xml if you are using maven, or simply drop the jar in you project's library folder
1. 将依赖 jars 导入到你的项目中，<dependency>如果你使用的是 maven，则在你的 pom.xml 中添加一个节点，或者简单地将 jar 放在你项目的库文件夹中
2.String jsonString = JSON.toJSONString(responseObj);(using fastjson)
2. String jsonString = JSON.toJSONString(responseObj);（使用fastjson）
回答by seballos
You can try to use JSONObject to parse the map to JSON.
您可以尝试使用 JSONObject 将映射解析为 JSON。
The maven dependency is:
Maven 依赖项是：
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20140107</version>
</dependency>
later create a new JSON object and pass the map
稍后创建一个新的 JSON 对象并传递地图
JSONObject obj = new JSONObject(responseObj);
and return the object to this web client.
并将对象返回到此 Web 客户端。
