List list;
if (collection instanceof List)
{
list = (List)collection;
}
else
{
list = new ArrayList(collection);
}
(java 1.5<=)public <E> List<E> collectionToList(Collection<E> collection)
{
List<E> list;
if (collection instanceof List)
{
list = (List<E>) collection;
}
else
{
list = new ArrayList<E>(collection);
}
return list;
}
public List collectionToList(Collection collection)
{
List list;
if (collection instanceof List)
{
list = (List) collection;
}
else
{
list = new ArrayList(collection);
}
return list;
}
Removing duplicate items from a list is pretty simple in java just convert the list to java.util.Set it will automatically remove the duplicate items and create a set for you.
Set<E> alphaSet = new HashSet<E>(<your List>);
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class ListToSet
{
public static void main(String[] args)
{
List<String> alphaList = new ArrayList<String>();
alphaList.add("A");
alphaList.add("B");
alphaList.add("C");
alphaList.add("A");
alphaList.add("B");
System.out.println("List values .....");
for (String alpha : alphaList)
{
System.out.println(alpha);
}
Set<String> alphaSet = new HashSet<String>(alphaList);
System.out.println("\nSet values .....");
for (String alpha : alphaSet)
{
System.out.println(alpha);
}
}
}
Today ,I faced a problem while running the tomcat with in the eclipse a popup appears
and it says:-
"Several ports (8005, 8080, 8009) required by Server (Tomcat 6) at localhost are already in use. The server may already be running in another process, or a system process may be using the port. To start this server you will need to stop the other process or change the port number(s)."
so it means we have kill that process which is running on that port says (8080).A pretty simple solution isrun the below commands on commands on command prompt.
C:\>netstat -a -o -n
C:\>taskkill /F /PID 3624
Hurry now you are able to run your server.
Un deployment of ext plugin in liferay is a tricky task, so i found a simple solution for doing this instead of deleting all the ext files from tomcat. I made a bat file for this this bat file remove all the ext plugin related files from your tomcat directory.
@echo off
set app_name=%1
if "%app_name%" == "" goto end
set tomcat_home=<Your tomcat home direcory>
rmdir /S /Q %tomcat_home%\temp
rmdir /S /Q %tomcat_home%\webapps\%app_name%-ext
rmdir /S /Q %tomcat_home%\webapps\ROOT\html\portlet\ext
del /S /Q %tomcat_home%\webapps\ROOT\WEB-INF\classes\portal-ext.properties
del /S /Q %tomcat_home%\lib\ext\ext-%app_name%-ext-service.jar
del /S /Q %tomcat_home%\webapps\ROOT\WEB-INF\lib\ext-%app_name%-ext-util-bridges.jar
del /S /Q %tomcat_home%\webapps\ROOT\WEB-INF\lib\ext-%app_name%-ext-util-taglib.jar
del /S /Q %tomcat_home%\webapps\ROOT\WEB-INF\lib\ext-%app_name%-ext-util-java.jar
del /S /Q %tomcat_home%\webapps\ROOT\WEB-INF\lib\ext-%app_name%-ext-impl.jar
del /S /Q %tomcat_home%\webapps\ROOT\WEB-INF\ext-%app_name%-ext.xml
del /S /Q %tomcat_home%\webapps\ROOT\WEB-INF\tiles-defs-ext.xml
:end
just change the tomcat_home with your tomcat home directory and paste the code in a notepad and save as undeployment.bat .
For running the bat pass your ext application name (with our ext) as command line argument.
C:/>undeployment.bat <application name>
Some times when we are trying to run build.xml using ant in eclipse it will gives an error "Specified VM install not found: type Standard VM, name jre6"
There is a simple solution for this just delete the launch file of that project.
Delete the file from the location given below
"<Your eclipse workspace location>\.metadata\.plugins\org.eclipse.debug.core\.launches\<projectname>.xml.launch"
Finally restart your eclipse.
Hurray !!! now your problem solved. :)
If you wanted to delete the stored subversion (svn) password from Eclipse IDE.
Then follow these steps :-
SVN stores the authentication in physical files. The easiest way is to delete those files physically from the directory.
On windows XP, these files are located in the following two folders:
Step 1 : Delete keyring file from the location given below
<Your eclipse installation path>\Eclipse\configuration\org.eclipse.core.runtime\.keyring
Step 2 : Delete all file from the location given below :-
C:\Documents and Settings\<your user name>\Application Data\Subversion\auth\svn.simple
Step 3 : Restart your Eclipse IDE, now all saved password will gone and a new prompt dialoge box will open for asking new password.
import java.util.ArrayList;
import java.util.List;
public class CheckList
{
public static void main(String[] args)
{
List<string> a = new ArrayList<string>();
a.add("a");
a.add("b");
List<string> b = new ArrayList<string>();
b.add("c");
b.add("a");
b.add("d");
b.add("f");
b.removeAll(a);
for (String str : b)
{
System.out.println(str);
}
}
}
Hi All,
Today I am going to discuss about a important jar commons-beanutils used by struts framework and demonstrating how to use this important jar in our servlet and jsp project.
If you worked with struts1 or struts2 then you noticed that the ActionForm or Action (in Struts2) linked with your Jsp page or html page when you clicked on submit button the values of html form with same property name is set by calling the setter method of your POJO or FormBean automatically.
But when we worked with only servlet and Jsp without using any MVC framework then we need to set the values using below line :-
String userName=request.getParameter(“userName”);
If we had 10 field on a form then we need to create 10 variables and we have to write the above line 10 times by passing the form filed name as argument.
Also another problem then we have to cast the filed values according to our need like
int age=Integer.parseInt(request.getParameter(“age”));
<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<form action="loginActionServlet" method="post">
<table>
<tbody>
<tr>
<td>Username</td>
<td>
<input name="userName" type="text">
</td>
</tr>
<tr>
<td>Password</td>
<td>
<input name="password" type="password">
</td>
</tr>
<tr>
<td>
<input type="submit">
</td>
</tr>
</tbody>
</table>
</form>
package form;
public class LoginForm {
private String userName;
private String password;
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
package util;
import java.lang.reflect.InvocationTargetException;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.beanutils.BeanUtils;
public class FormUtil {
public static <T> T populate(Class<T> clazz, HttpServletRequest request) {
T object = null;
try {
object = (T) clazz.newInstance();
BeanUtils.populate(object, request.getParameterMap());
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
return object;
}
}
package action;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import util.FormUtil;
import form.LoginForm;
public class LoginActionServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
LoginForm loginForm = FormUtil.populate(LoginForm.class, request);
out.println("User name is :" + loginForm.getUserName());
out.println("Password is :" + loginForm.getPassword());
}
}
<web-app id="WebApp_ID" version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemalocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>DemoApp</display-name>
<servlet>
<display-name>LoginActionServlet</display-name>
<servlet-name>LoginActionServlet</servlet-name>
<servlet-class>action.LoginActionServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginActionServlet</servlet-name>
<url-pattern>/loginActionServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
Now paste these files according to package structure and run it by typing http://localhost:8080/DemoApp.
enum Day {
SUNDAY(1), MONDAY(2), TUESDAY(3), WEDNESDAY(4), THURSDAY(5), FRIDAY(6), SATURDAY(7);
private final int dayCode;
private Day(int dayCode)
{
this.dayCode = dayCode;
}
public int getCode() { return dayCode; }
}
public class EnumValueOfDay {
public static void main(String[] args) {
Day day = Day.SUNDAY;
System.out.println("Day = " + day.getCode());
}
}
also you can use enum in this way to get the value of enum . Here is one more example to print the names by using toString method.
enum Name {
S("Sandeep"),
A("Aditya") ,
R("Rambrij"),
M("Meenakshi");
private final String name;
private Name(String name) {
this.name = name;
}
public String toString() {
return name;
}
}
public class NameDisplay {
public static void main(String[] args) {
Name name = Name.A;
System.out.println("Name = " + name);
}
}