javabeans

DBUtils fails to fill fields of a Java Bean

由 时间秒杀一切 提交于 2019-11-30 20:41:13
问题 I have a mysql table like this: CREATE TABLE `sezione_menu` ( `id_sezione_menu` int(11) unsigned NOT NULL AUTO_INCREMENT, `nome` varchar(256) NOT NULL DEFAULT '', `ordine` int(11) DEFAULT NULL, PRIMARY KEY (`id_sezione_menu`) )ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8; I use apache dbutils to query my database, with these methods: public static List<SezioneMenu> getSezioniMenu() { String sql = "SELECT * FROM sezione_menu"; try { QueryRunner qr = new QueryRunner(createDataSource());

Using beans in servlets

由 99封情书 提交于 2019-11-30 19:02:09
问题 I has a jsp page (index.jsp) with a form with two text fileds username and password like. <form action="MyClass"> <input type="text" name="username" id="username" /> <input type="password" name="password" id="password" /> <input type="submit" /> </form> On form submition i am invocking a servlet. I know that we can get the entered username and password values by using request methods, request.getParameter("username"); request.getParameter("password"); But i don't want to use them , instead i

Does EL automatically convert/cast the type? How does ${a.name} actually work?

由 吃可爱长大的小学妹 提交于 2019-11-30 17:51:45
问题 I have a variable declared as type Object a which actually refers an instance of type A . In EL, I can directly use the following expression to print the name property of type A : ${a.name} How does it work? 回答1: EL uses reflection under the hoods, usually via javax.beans.Introspector API. This is what it roughly does under the covers on ${a.name} . // EL will breakdown the expression. String base = "a"; String property = "name"; // Then EL will find the object and getter and invoke it.

Java Beans, BeanUtils, and the Boolean wrapper class

由 只谈情不闲聊 提交于 2019-11-30 17:37:17
I'm using BeanUtils to manipulate Java objects created via JAXB, and I've run into an interesting issue. Sometimes, JAXB will create a Java object like this: public class Bean { protected Boolean happy; public Boolean isHappy() { return happy; } public void setHappy(Boolean happy) { this.happy = happy; } } The following code works just fine: Bean bean = new Bean(); BeanUtils.setProperty(bean, "happy", true); However, attempting to get the happy property like so: Bean bean = new Bean(); BeanUtils.getProperty(bean, "happy"); Results in this exception: Exception in thread "main" java.lang

Jackson - Java bean to JSON string : uppercase variable converted into lowercase in JSON

由 ≡放荡痞女 提交于 2019-11-30 16:12:45
I am converting Java bean to JSON string using writeValueAsString method of ObjectMapper where uppercase variables from Java bean is being changed to lowercase in JSON string. Jackson 2.7.4 version implemented. Base bean sample - public class BaseBean { private static final long serialVersionUID = 3947489072259877540L; private int _iXId; private String _sPNR; private ArrayList _alMinPriced = new ArrayList<TermBean>(); public int getXId() { return _iXId; } public void setXId(int id) { _iXId = id; } public String getPNRNumber() { return _sPNR; } public void setPNRNumber(String _spnr) { _sPNR =

Java comparator for multi-column sorting?

由 匆匆过客 提交于 2019-11-30 13:46:10
Is there any Java open-source comparator for comparing beans by multiple fields for multi-column sorting? Each column can be sorted asceding or descending. For single-column sorting it can be achieved by using org.apache.commons.beanutils.BeanComparator together with org.springframework.util.comparator.InvertibleComparator . I'm aware that this functionality is quite trivial to write, but what's the benefit from reinventing the wheel, if it was already written and tested? I wrote this a few months ago. public abstract class ChainedComparator<T> implements Comparator<T> { private Comparator<T>

difference between java bean and java class?

由 有些话、适合烂在心里 提交于 2019-11-30 13:44:21
问题 I am new to the JSP and server side programming. Till now I am working with Servlets and java classes. I am segregating my application (as per MVC model) with the help of java classes. I would like to know difference between java beans and java classes. And in which scenario I can use a java bean instead of a java class. Any helpful explanation or helpful links? 回答1: A Java bean is just a class which conforms to some conventions: properties that can be accessed by getters (and setters if

How to pass parameters dynamically to Spring beans

由 自闭症网瘾萝莉.ら 提交于 2019-11-30 12:50:10
问题 I am new to Spring. This is the code for bean registration: <bean id="user" class="User_Imple"> </bean> <bean id="userdeff" class="User"> </bean> and this is my bean class: public class User_Imple implements Master_interface { private int id; private User user; // here user is another class public User_Imple() { super(); } public User_Imple(int id, User user) { super(); this.id = id; this.user = user; } // some extra functions here.... } and this is my main method to perform action: public

Accessing Spring beans from servlet filters and tags

由 爷，独闯天下 提交于 2019-11-30 12:33:19
问题 I can access Spring beans in my Servlets using WebApplicationContext springContext = WebApplicationContextUtils.getWebApplicationContext(getServletContext()); in the Servlet's init method. I was wondering is there an equivalent of the WebApplicationContext for servlet filters? Also, is it possible to access Spring beans in a tag class? 回答1: For filters - use Filter.init() : public void init(FilterConfig config) { WebApplicationContext springContext = WebApplicationContextUtils

Java Spring Recreate specific Bean

由 烂漫一生 提交于 2019-11-30 11:29:36
I want to re-create (new Object) a specific bean at Runtime (no restarting the server) upon some DB changes. This is how it looks - @Component public class TestClass { @Autowired private MyShop myShop; //to be refreshed at runtime bean @PostConstruct //DB listeners public void initializeListener() throws Exception { //... // code to get listeners config //... myShop.setListenersConfig(listenersConfig); myShop.initialize(); } public void restartListeners() { myShop.shutdownListeners(); initializeListener(); } } This code does not run as myShop object is created by Spring as Singleton & its
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