如何提取JSON字符串GSON

单独对象

String config = "{contact:{\"FIRSTNAME\":\"C_FirstName\",\"EMAIL\":\"C_EmailAddress\"}, " 
          + "customobject:{\"CUSTOM_FIELD1\":\"Custom_Field__11\"," 
          + "\"FIRSTNAME\":\"First_Name1\",\"EMAIL\":\"Email_Address1\"}}";

我需要提取每一个对象，即contact和customobject为String所以最终的结果应该是：

String contact = "{\"FIRSTNAME\":\"C_FirstName\",\"EMAIL\":\"C_EmailAddress\"}"; 
String customobject = "{\"CUSTOM_FIELD1\":\"Custom_Field__11\"," 
         + "\"FIRSTNAME\":\"First_Name1\",\"EMAIL\":\"Email_Address1\"}";

这是需要使用Gson此所以我想以下几点：

Map<String, String> map = gson.fromJson(config, new TypeToken<Map<String,Object>>(){}.getType()); 

String json = map.get("contact").toString();

，但我得到了以下错误：

java.lang.ClassCastException: com.google.gson.internal.StringMap cannot be cast to java.lang.String

什么是实现这一目标的正确方法？

来源

2017-06-16 esteban rincon

发现我的解决方案：

import java.util.Map; 

import com.google.gson.Gson; 
import com.google.gson.JsonElement; 
import com.google.gson.reflect.TypeToken; 

public class JsonTest { 


    static String config = "{contact:{\"FIRSTNAME\":\"C_FirstName\",\"EMAIL\":\"C_EmailAddress\"}, " 
          + "customobject:{\"CUSTOM_FIELD1\":\"Custom_Field__11\"," 
          + "\"FIRSTNAME\":\"First_Name1\",\"EMAIL\":\"Email_Address1\"}}"; 

    String contact = "{\"FIRSTNAME\":\"C_FirstName\",\"EMAIL\":\"C_EmailAddress\"}"; 
    String customobject = "{\"CUSTOM_FIELD1\":\"Custom_Field__11\"," 
          + "\"FIRSTNAME\":\"First_Name1\",\"EMAIL\":\"Email_Address1\"}"; 

    public static void main(String[] args) { 

     Gson gson = new Gson(); 

     Conf c = gson.fromJson(config, Conf.class); 

     String contactStr = gson.toJson(c.getContact()); 

     System.out.println(contactStr); 

    } 

    class Conf{ 

     Map<String, String> contact; 
     Map<String, String> co; 
     public Map<String, String> getContact() { 
      return contact; 
     } 
     public void setContact(Map<String, String> contact) { 
      this.contact = contact; 
     } 
     public Map<String, String> getCo() { 
      return co; 
     } 
     public void setCo(Map<String, String> co) { 
      this.co = co; 
     } 


    } 
}

来源

2017-06-16 04:05:16

尝试这个

创建类配置，联系方式和CustomObject给出下面

class Config implements Serializable { 
Contact contact; 
CustomObject customobject; 

public Config() { 
    this(new Contact("",""), new CustomObject("", "", "")); 
} 

public Config(Contact contact, CustomObject customobject) { 
    this.contact = contact; 
    this.customobject = customobject; 
} 

public Contact getContact() { 
    return contact; 
} 

public void setContact(Contact contact) { 
    this.contact = contact; 
} 

public CustomObject getCustomobject() { 
    return customobject; 
} 

public void setCustomobject(CustomObject customobject) { 
    this.customobject = customobject; 
} 
} 

class Contact implements Serializable{ 

String FIRSTNAME; 
String EMAIL; 

public Contact() { 
    this("",""); 
} 

public Contact(String FIRSTNAME, String EMAIL) { 
    this.FIRSTNAME = FIRSTNAME; 
    this.EMAIL = EMAIL; 
} 

public String getEMAIL() { 
    return EMAIL; 
} 

public void setEMAIL(String EMAIL) { 
    this.EMAIL = EMAIL; 
} 

public String getFIRSTNAME() { 
    return FIRSTNAME; 
} 

public void setFIRSTNAME(String FIRSTNAME) { 
    this.FIRSTNAME = FIRSTNAME; 
} 
} 

class CustomObject implements Serializable { 

String CUSTOM_FIELD1; 
String FIRSTNAME; 
String EMAIL; 

public CustomObject() { 
    this("", "", ""); 
} 

public CustomObject(String CUSTOM_FIELD1, String FIRSTNAME, String EMAIL) { 
    this.CUSTOM_FIELD1 = CUSTOM_FIELD1; 
    this.FIRSTNAME = FIRSTNAME; 
    this.EMAIL = EMAIL; 
} 

public String getCUSTOM_FIELD1() { 
    return CUSTOM_FIELD1; 
} 

public void setCUSTOM_FIELD1(String CUSTOM_FIELD1) { 
    this.CUSTOM_FIELD1 = CUSTOM_FIELD1; 
} 

public String getFIRSTNAME() { 
    return FIRSTNAME; 
} 

public void setFIRSTNAME(String FIRSTNAME) { 
    this.FIRSTNAME = FIRSTNAME; 
} 

public String getEMAIL() { 
    return EMAIL; 
} 

public void setEMAIL(String EMAIL) { 
    this.EMAIL = EMAIL; 
} 
}

现在分析它使用GSON作为低于

String config = "{contact 
{\"FIRSTNAME\":\"C_FirstName\",\"EMAIL\":\"C_EmailAddress\"}, " 
     + "customobject:{\"CUSTOM_FIELD1\":\"Custom_Field__11\"," 
     + 
"\"FIRSTNAME\":\"First_Name1\",\"EMAIL\":\"Email_Address1\"}}"; 

try { 
    Gson gson = new Gson(); 

    Config config1 = gson.fromJson(config, Config.class); 

    System.out.println(config1.getContact().FIRSTNAME); 
    System.out.println(config1.getContact().EMAIL); 

    System.out.println(config1.getCustomobject().CUSTOM_FIELD1); 
    System.out.println(config1.getCustomobject().FIRSTNAME); 
    System.out.println(config1.getCustomobject().EMAIL); 


} catch (JsonSyntaxException e) { 
    e.printStackTrace(); 
}

NOTE : Please Follow Best Practices For Naming Conventions. You are using wrong one.

来源

2017-06-16 04:35:18 Abhishek

如果你简单地提取JSON属性值，你不需要你的反序列化和序列化的步骤。您所要做的就是使JSON树模型脱离JSON输入数据并寻址目标对象。在Gson有JsonElement s为这（和那）目的服务。

private static final JsonParser jsonParser = new JsonParser(); 

public static void main(final String... args) { 
    final String config = "{contact:{\"FIRSTNAME\":\"C_FirstName\",\"EMAIL\":\"C_EmailAddress\"}, " 
      + "customobject:{\"CUSTOM_FIELD1\":\"Custom_Field__11\"," 
      + "\"FIRSTNAME\":\"First_Name1\",\"EMAIL\":\"Email_Address1\"}}"; 
    final JsonObject rootObject = jsonParser.parse(config).getAsJsonObject(); 
    System.out.println(rootObject.get("contact")); 
    System.out.println(rootObject.get("customobject")); 
}

输出：

{"FIRSTNAME":"C_FirstName","EMAIL":"C_EmailAddress"}
{"CUSTOM_FIELD1":"Custom_Field__11","FIRSTNAME":"First_Name1","EMAIL":"Email_Address1"}

每个JsonElement子类都有自己的toString()实施产生它的JSON字符串表示。有关详细信息，请参阅Gson JsonElement和JsonParser JavaDocs。

来源

2017-06-16 05:00:31

如何提取JSON字符串GSON

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