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[英]composed primary key using hibernate with spring data jpa and mysql
[英]retrieving data from mysql using hibernate without primary key in restful web service
我正在使用restful web service
開發Web應用程序。 我已經使用了hibernate
和POJO
進行mysql communication
。
我有具有用戶表的數據庫,主要數據庫是empid
。 為了獲得單行,我將empid從html頁面傳遞到了Web服務,並將json對象返回到html頁面(使用javascript進行解析)。
我已經使用這一行從數據庫where empid=277;
獲得單行, where empid=277;
//在這里硬編碼
new_user =(用戶)session.get(User.class,(long)277);
我想從employeeid的其他列中檢索記錄(NOT empid,empid是主鍵)
select * user where employeeid="XX-123XD"
我已經從html頁面(字符串)傳遞了employeeid
。
我寫過像
@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;
}
但是我得到這樣的錯誤,
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)
如果我刪除了Query語句,並取消注釋代碼,則該塊為
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();
然后它可以工作並給出empid=277
的預期結果,這是主鍵。
我在做錯查詢。 還有休眠是否有其他方法可以在沒有主鍵的情況下獲取數據,例如
`new_user = (User) session.get(User.class, employeeid);`
|
String(Not the primary key)
我的JSON對象的jsp文件是
<%
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);
%>
我試過使用new_user = (User) query.uniqueResult();
然后也發生了相同的錯誤JSONObject jsonobj = cliresponse.getEntity(JSONObject.class);
謝謝
請使用查詢方法uniqueResult()。
Query query = session.createQuery("from user where employeeid= :employee");
query.setParameter("employee", employeeid);
new_user = (User) query. uniqueResult();
您發布的客戶端異常無濟於事,可以提供服務器端異常stacktrace嗎? 我們必須知道什么冬眠的抱怨
解決,
代替
Query query = session.createQuery("from user where employeeid= :employee");
query.setParameter("employee", employeeid);
我已經添加了,
Query query = session.createQuery("from user where employeeid='" + employeeid + "'");
而且效果很好
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