在宁静的Web服务中使用没有主键的Hibernate从MySQL检索数据

Question

I am developing web application using restful web service . I have used hibernate and POJO to mysql communication .

I have database which has the user table and the primary is the empid . For getting the single row, I have passed the empid from html page to the web service and return the json object to the html page(javascript is used for parsing).

I have used this one to get the single row from DB where empid=277; // Hardcoded here

new_user = (User) session.get(User.class, (long)277);

I want to retrieve record from other column like employeeid( NOT empid,empid is primary key)

select * user where employeeid="XX-123XD"

I have passed the employeeid from html page which is string.

I have written web service like

    @POST
    @Path("/getjson")
    @Produces("application/json")
    public JSONObject sendjson(String employeeid) {

            Gson gsonobj = new Gson();
            JSONObject jsonobj = null;

            SessionFactory fact;
            fact = new Configuration().configure().buildSessionFactory();
            User new_user = null;

            Session session = fact.getCurrentSession();
            Transaction tx =  session.beginTransaction();
            Query query = session.createQuery("from user where employeeid= :employee");
            query.setParameter("employee", employeeid);
            //new_user = (User) session.get(User.class, (long)277);
            new_user = (User) query.list();

        try {    
            String jsonstr = gsonobj.toJson(new_user);
            jsonobj = new JSONObject(jsonstr);
        } catch (JSONException ex) {
            Logger.getLogger(Authneticate.class.getName()).log(Level.SEVERE, null, ex);
        }
        return jsonobj;
    }

But i get the error like,

type Exception report

message com.sun.jersey.api.client.ClientHandlerException: A message body reader for Java class org.codehaus.jettison.json.JSONObject, and Java type class org.codehaus.jettison.json.JSONObject, and MIME media type text/html; charset=utf-8 was not found

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: com.sun.jersey.api.client.ClientHandlerException: A message body reader for Java class org.codehaus.jettison.json.JSONObject, and Java type class org.codehaus.jettison.json.JSONObject, and MIME media type text/html; charset=utf-8 was not found
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:549)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
root cause

com.sun.jersey.api.client.ClientHandlerException: A message body reader for Java class org.codehaus.jettison.json.JSONObject, and Java type class org.codehaus.jettison.json.JSONObject, and MIME media type text/html; charset=utf-8 was not found
    com.sun.jersey.api.client.ClientResponse.getEntity(ClientResponse.java:561)
    com.sun.jersey.api.client.ClientResponse.getEntity(ClientResponse.java:517)
    org.apache.jsp.HomeUser_jsp._jspService(HomeUser_jsp.java:91)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

If I removed Query statements, and uncomment the code then that block is

    Session session = fact.getCurrentSession();
    Transaction tx =  session.beginTransaction();
    //Query query = session.createQuery("from user where employeeid= :employee");
    //query.setParameter("employee", employeeid);
    new_user = (User) session.get(User.class, (long)277);
    //new_user = (User) query.list();

then it works and gives the expected result for empid=277 which is primary key.

What I am doing wrong with Query. And Is there any other way with hibernate to get data without primary key like

`new_user = (User) session.get(User.class, employeeid);`
                                                  |
                                          String(Not the primary key)

My jsp file which gets the JSON object is

<%

Client client = Client.create();
WebResource service = client.resource("http://localhost:8080/ITHelpdesk/webresources/hello/getjson");
String input = request.getParameter("username");
ClientResponse cliresponse = service.type("text/html").post(ClientResponse.class,input);
JSONObject jsonobj = cliresponse.getEntity(JSONObject.class);

%>

I have tried using using new_user = (User) query.uniqueResult(); Then also same error occurred JSONObject jsonobj = cliresponse.getEntity(JSONObject.class);

Thank you

Answer 1

Please use Query method uniqueResult().

 Query query = session.createQuery("from user where employeeid= :employee");
 query.setParameter("employee", employeeid);
 new_user = (User) query. uniqueResult();

Answer 2

the client side exception you posted doesn't help, can you provide the server side exception stacktrace? we have to know what hibernate complaints

Answer 3

resolved,

instead of

Query query = session.createQuery("from user where employeeid= :employee");
query.setParameter("employee", employeeid);

I have added,

Query query = session.createQuery("from user where employeeid='" + employeeid + "'");

And it works fine