java.lang.ClassCastException: org.json.simple.JSONArray cannot be cast to org.json.JSONArray

问题

I need to read a JsonArray data from a file (on an SD card) and store it into a SQLite database.

but I am getting a java.lang.ClassCastException: org.json.simple.JSONArray cannot be cast to org.json.JSONArray exception while parsing data to JsonArray.

Data in the file is very huge, the whole data can not be stored in a single String or String Buffer or String Builder.

Here is my code.

FileReader fileReader = new FileReader(file_path);
Object obj = jsonParser.parse(fileReader);
JSONArray jsonArray = (JSONArray) obj; // Exception.

Please help..

回答1:

Check your import statements at the top of your source file.

You probably have a line saying:

import org.json.JSONArray;

It should instead be:

import org.json.simple.JSONArray;

If you are working in eclipse, or any other intelligent IDE, the problem probably happened when you started typing the line starting with JSONArray. At that point, the IDE would show you different possibilities of importing the class JSONArray. You have one in org.json.JSONArray and one in org.json.simple.JSONArray. The latter is the right one, but you choose the first one and your IDE automatically added an import line at the top of your source java file.

From the exception the problem is quite apparent, the exception tells you that your obj object cannot be cast to a org.json.JSONArray object as it is really a org.json.simple.JSONArray object. (Note that there is a different between the two).

Update

If you want to use org.json.JSONArray instead, you should use another class than jsonParser as this one is from the org.json.simple package. Currently you are mixing the two libraries, and that is what causes your troubles.

回答2:

You can first read the whole content of file into a String.

FileInputStream fileInputStream = null;
String data="";
StringBuffer stringBuffer = new StringBuffer("");
try{
    fileInputStream=new FileInputStream(filename);
    int i;
    while((i=fileInputStream.read())!=-1)
    {
        stringBuffer.append((char)i);
    }
    data = stringBuffer.toString();
    csvFile.delete();
}
catch(Exception e){
        LoggerUtil.printStackTrace(e);
}
finally{
    if(fileInputStream!=null){  
        fileInputStream.close();
    }
}

Now You will have the whole content into String ( data variable ).

JSONParser parser = new JSONParser();
org.json.simple.JSONArray jsonArray= (org.json.simple.JSONArray) parser.parse(data);

After that you can use jsonArray as you want.

来源：https://stackoverflow.com/questions/20652284/java-lang-classcastexception-org-json-simple-jsonarray-cannot-be-cast-to-org-js

标签

java

android

json

classcastexception

filereader