javabeans

Why Java Beans have to be serializable?

由 可紊 提交于 2019-11-27 21:41:23
问题 Is it necessary that a Java Bean implements the Serializable interface? 回答1: It's one of the "typical" features as described in the Javabeans specification. Here's an extract of chapter 2.1 What is a bean? Individual Java Beans will vary in the functionality they support, but the typical unifying features that distinguish a Java Bean are: Support for “introspection” so that a builder tool can analyze how a bean works Support for “customization” so that when using an application builder a user

JasperReports: How to call a java bean method in report template?

由 微笑、不失礼 提交于 2019-11-27 21:31:23
I am passing a java bean collection into a jasper report. I have several fields for this java bean defined an they are display just fine in my report. Im wondering if there is a way to call a method of a java bean that is being passed into this report??? E.g. an expression for a text field, something like.... {current java bean}.methodToCall() Using the keyword _THIS in a field name or description will make it map to the bean class itself. Using the fieldDescription tag is better as it allows you to do this with multiple beans. For example: <field name="customBean" class="com.example

Difference between JavaBean and Spring bean

由 拥有回忆 提交于 2019-11-27 20:02:17
问题 I am new to Spring MVC and have a little idea of the usage of java beans in Java. What is the basic difference between a Java bean and Spring bean? 回答1: JavaBeans: At a basic level, JavaBeans are simply Java classes which adhere to certain coding conventions. Specifically, classes that have public default (no argument) constructors allow access to their properties using accessor (getter and setter) methods implement java.io.Serializable Spring Beans: A Spring bean is basically an object

Valid JavaBeans names for boolean getter methods

由 给你一囗甜甜゛ 提交于 2019-11-27 18:27:17
I know most variable names will work with "is", such as isBlue() , but is "has" also a valid prefix, like hasProperty() ? Jon Skeet According to the JavaBeans specification section 8.3.2: Boolean properties In addition, for boolean properties, we allow a getter method to match the pattern: public boolean is<PropertyName>(); This " isPropertyName " method may be provided instead of a " get<PropertyName> " method, or it may be provided in addition to a " get<PropertyName> " method. In either case, if the is<PropertyName> method is present for a boolean property then we will use the " is

Java Spring bean with private constructor

由 ≡放荡痞女 提交于 2019-11-27 18:21:30
Is possible in Spring that class for bean doesn't have public constructor but only private ? Will this private constructor invoked when bean is created? Thanks. Yes, Spring can invoke private constructors. If it finds a constructor with the right arguments, regardless of visibility, it will use reflection to set its constructor to be accessible. You can always use a factory method to create beans rather than relying on a default constructor, from The IoC container: Instantiation using an instance factory method : <!-- the factory bean, which contains a method called createInstance() --> <bean

Declaring an array of objects in a Spring bean context

由 无人久伴 提交于 2019-11-27 17:21:47
问题 I'm trying to create an array of objects in a Spring context file so I can inject it to a constructor that's declared like this: public RandomGeocodingService(GeocodingService... services) { } I'm trying to use the <array> tag: <bean id="googleGeocodingService" class="geocoding.GoogleGeocodingService"> <constructor-arg ref="proxy" /> <constructor-arg value="" /> </bean> <bean id="geocodingService" class="geocoding.RandomGeocodingService"> <constructor-arg> <array value-type="geocoding

Why shouldn't I use immutable POJOs instead of JavaBeans?

由 好久不见. 提交于 2019-11-27 16:55:28
I have implemented a few Java applications now, only desktop applications so far. I prefer to use immutable objects for passing the data around in the application instead of using objects with mutators (setters and getters ), also called JavaBeans. But in the Java world, it seems to be much more common to use JavaBeans, and I can't understand why I should use them instead. Personally the code looks better if it only deals with immutable objects instead of mutate the state all the time. Immutable objects are also recommended in Item 15: Minimize mutability , Effective Java 2ed . If I have an

how to generically compare entire java beans?

由 扶醉桌前 提交于 2019-11-27 16:00:00
I've been trying to grok the org.apache.commons.beanutils library for a method/idiom to evaluate for equality all properties between 2 instances i.e. a generic equals() method for beans. Is there a simple way to do this usnig this library? Or am I going about this the wrong way? Thanks. Aaron Digulla Try EqualsBuilder.reflectionEquals() of commons-lang . EqualsBuilder has a set of methods to include all fields, all non-transient fields and all but certain fields. If all else fails, the code could serve as a good example how to implement this. Rolf To answer your question directly, you could

boolean properties starting with “is” does not work

由 一个人想着一个人 提交于 2019-11-27 15:06:28
问题 I have a project that use JSF 2.1 and PrimeFaces. I tried to use a simple <h:outputText> referencing #{myBean.matriz} and I got this error: SEVERE: javax.el.PropertyNotFoundException: ... value="#{myBean.matriz}": Missing Resource in EL implementation: ???propertyNotReadable??? The getter is: isMatriz() . Should it be getMatriz() ? 回答1: The is prefix works only for boolean , not Boolean . You've there apparently actually a Boolean property. You've 2 options to fix it: Rename the getter with

jsp useBean is NULL by getAttribute by servlet

由 守給你的承諾、 提交于 2019-11-27 14:52:57
user is null in servlet. Pls let me if doing mistake. i m trying to get all html element in bean rateCode.jsp <%@page import="com.hermes.data.RateCode_" %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html> <head> <title>Rate Code</title> </head> <body> <jsp:useBean id="user" class="com.hermes.data.RateCode_" scope="request" > <jsp:setProperty name="user" property="*"/></jsp:useBean> <form id="f_rateCode" action="/ratePromoCodes" method="post" > <table align="center" border="1" cellspacing="0"> <tr> <td colspan="2" align="center" class="header">Rate Code Administrations</td>
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