java解析json文件

我之前800万条数据以类似的方式读出来，30000条问题不大吧

public class Util {

public String ReadFile(String Path){
BufferedReader reader = null;
String laststr = "";
try{
FileInputStream fileInputStream = new FileInputStream(Path);
InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "UTF-8");
reader = new BufferedReader(inputStreamReader);
String tempString = null;
while((tempString = reader.readLine()) != null){
laststr += tempString;
}
reader.close();
}catch(IOException e){
e.printStackTrace();
}finally{
if(reader != null){
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return laststr;
}

}
（2）Test.java:
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

public class Test {

public static void main(String[] args) {
// TODO Auto-generated method stub
String JsonContext = new Util().ReadFile("D:\\test\\apkinfo.json");
JSONArray jsonArray = JSONArray.fromObject(JsonContext);
int size = jsonArray.size();
System.out.println("Size: " + size);
for(int  i = 0; i < size; i++){
JSONObject jsonObject = jsonArray.getJSONObject(i);
System.out.println("[" + i + "]name=" + jsonObject.get("name"));
System.out.println("[" + i + "]package_name=" + jsonObject.get("package_name"));
System.out.println("[" + i + "]check_version=" + jsonObject.get("check_version"));
}
}

}