Div R Div R - 5 months ago 60
Java Question

FlexJson Error : ClassCastException: java.util.HashMap cannot be cast to class

This is the error I get while I try to cast my LONGTEXT object from mysql back to my ProcessInputs java object using FlexJSON.

java.lang.ClassCastException: java.util.HashMap cannot be cast to org.juzzy.server.ProcessInputs
at org.juzzy.server.FLSDAO.RetrieveFLSFromDatabase(FLSDAO.java:68)
at org.juzzy.client.CreateFLS.doPost(CreateFLS.java:48)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)


This is what my ProcessInput class looks like

public class ProcessInputs {
//inputs contain names of all the inputs and their objects
Map<String,Input> inputs= new LinkedHashMap<String,Input>();
Map<String,Output> outputs= new HashMap<String,Output>();
Map<String,Object> fuzzyTerms=new HashMap<String,Object>();
Map<String,String> fuzzyTermMapper=new HashMap<String,String>();
ArrayList<T1_Antecedent> antecedentArrayList;
String outputxml;
T1_Rulebase rulebase = new T1_Rulebase(1);
//getters,setters, constructor and functions
}


My retrieval code in FLEXJSON:

while(rs.next()){
String jsonInString= rs.getString("fls");
JSONDeserializer<ProcessInputs> der = new JSONDeserializer<ProcessInputs>();
ProcessInputs fls = der.deserialize(jsonInString);

}


This is how the serialization happens:

public boolean InsertFLStoDatabase(ProcessInputs object, String xml) throws IOException {
Connection connection = DatabaseConnect.getConnection();
String query = "insert into fls_systems (fls, xml) values (?,?)";
try {
JSONSerializer ser = new JSONSerializer();
String jsonInString = ser.deepSerialize(object);
PreparedStatement ps = connection.prepareStatement(query);
ps.setString(1, jsonInString);

Answer

From your exception this should work (i guess...):

while(rs.next()){
    String jsonInString= rs.getString("fls");
    JSONDeserializer<ProcessInputs> der = new JSONDeserializer<ProcessInputs>();
    // exception is here, right? der.deserialize(String) is giving you a Map!!
    Map<String,Input> fls = der.deserialize(jsonInString);
}

Don't have a deep knowledge of flexjson, but I'm not casting like

Map<String,Input> fls = (Map<String,Input>) der.deserialize(jsonInString);

Because of the message:

java.util.HashMap cannot be cast to org.juzzy.server.ProcessInputs

And because API:

Deserialize the given json formatted input into a Java object.

But may be a possibility if first option does not work.

Comments