Friday 31 August 2012

Read xls or excel file from server and parse xls or excel file


CHANGE THIS BOLD URL WITH YOUR FILE ADDRESS WITH SERVER ADDRESS AND THEN JUST COPY PASTE THE CODE TO JAVA FILE.


NOTE : U MUST HAVE TO ADD JAR FILE TO YOUR PROJECT CLASS PATH FROM THIS http://jexcelapi.sourceforge.net/  DOWN LOAD JAR FILE FROM HERE IF JAR IS NOT AVAILABLE ON THIS URL THEN SEARCH JXL JAR AND DOWNLOAD IT.

import java.io.IOException; import jxl.Cell; import jxl.CellType; import jxl.Sheet; import jxl.Workbook; import jxl.read.biff.BiffException; import java.net.URLConnection; public class ReadExcel { public void read() throws IOException { java.net.URL url = new java.net.URL("http://www.XYZ.org/alphaguru.xls"); URLConnection conn = url.openConnection(); conn.setRequestProperty("Connection","Keep-Alive"); conn.setConnectTimeout(10000); System.out.println("value of sTring is:"+conn.getInputStream().toString()); Workbook w; try { w = Workbook.getWorkbook(conn.getInputStream()); // Get the first sheet Sheet sheet = w.getSheet(0); // Loop over first 10 column and lines for (int j = 0; j < sheet.getColumns(); j++) { for (int i = 0; i < sheet.getRows(); i++) { Cell cell = sheet.getCell(j, i); if (cell.getType() == CellType.LABEL) { System.out.println("I got a label "+ cell.getContents()); } if (cell.getType() == CellType.NUMBER) { System.out.println("I got a number "+ cell.getContents()); } } } } catch (BiffException e) { e.printStackTrace(); } } public static void main(String[] args) throws IOException { ReadExcel test = new ReadExcel(); test.read(); } }

Difference between Hibernate createCriteria, createQuery, createSQLQuery function

To create query in the Hibernate ORM framework, there is three different types. The following are the three ways to create query instance: - session.createQuery() - session.createSQLQuery() - session.createCriteria() look into the details of each category in detail. session.createQuery() The method createQuery() creates Query object using the HQL syntax. Fro example Query query = session.createQuery("from Student s where s.name like 'k%'"); session.createSQLQuery() The method createSQLQuery() creates Query object using the native SQL syntax. Fro example Query query = session.createQuery("Select * from Student"); session.createCriteria() The method createCriteria() creates Criteria object for setting the query parameters. This is more useful feature for those who don't want to write the query in hand. You can specify any type of complicated syntax using the Criteria API. Criteria criteria = session.createCriteria(Student.class);

Thursday 30 August 2012

com.sun.jersey.api.client.ClientHandlerException: java.net.ConnectException

Problem

Connection refused :
com.sun.jersey.api.client.ClientHandlerException: java.net.ConnectException: Connection refused
 
 ...
 
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
 at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
 at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999)
 at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
 at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
 at java.lang.Thread.run(Thread.java:679)

Solution

- Check your port number.
- Start your service.

java.lang.ClassCastException: java.util.Collections$SynchronizedMap

Problem

private static HashMap<String, Long> orderProcessmap = null;
orderProcessmap =  Collections.synchronizedMap((new HashMap<String, Long>()));
java.lang.ClassCastException: java.util.Collections$SynchronizedMap cannot be cast to java.util.HashMap
 at .......org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1266)
 at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1185)
 at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1080)
 at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5015)
 at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5302)
 at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
 at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:895)
 at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:871)
 at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:615)
 at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:962)
 at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1603)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
 at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
 at java.util.concurrent.FutureTask.run(FutureTask.java:166)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
 at java.lang.Thread.run(Thread.java:679)

Solution

private static Map<String, Long> map = null;
map =  Collections.synchronizedMap((new HashMap<String, Long>()));

Wednesday 29 August 2012

Java.Lang.ClassNotFoundException : Javassist.Util.Proxy.MethodFilter

Problem

Using Hibernate 3.6.3, but hits this javassist not found error, see below for error stacks :
Caused by: java.lang.NoClassDefFoundError: javassist/util/proxy/MethodFilter
 ...
 at org.hibernate.tuple.entity.PojoEntityTuplizer.<init>(PojoEntityTuplizer.java:77)
 ... 16 more
Caused by: java.lang.ClassNotFoundException: javassist.util.proxy.MethodFilter
 at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
 at java.security.AccessController.doPrivileged(Native Method)
 at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
 at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
 at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
 at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
 ... 21 more

Solution

javassist.jar is missing,