java

RxJava: combine two optional observables

由 烈酒焚心 提交于 2021-02-19 04:09:14
问题 I have two Observable s, let's call them PeanutButter and Jelly . I'd like to combine them to a Sandwich Observable . I can do that using: Observable<PeanutButter> peanutButterObservable = ...; Observable<Jelly> jellyObservable = ...; Observable<Sandwich> sandwichObservable = Observable.combineLatest( peanutButterObservable, jellyObservable, (pb, j) -> makeSandwich(pb, j)) The problem is that RX waits for the first PeanutButter and the first Jelly to be emitted before emitting the first

RxJava: combine two optional observables

由 守給你的承諾、 提交于 2021-02-19 04:08:20
问题 I have two Observable s, let's call them PeanutButter and Jelly . I'd like to combine them to a Sandwich Observable . I can do that using: Observable<PeanutButter> peanutButterObservable = ...; Observable<Jelly> jellyObservable = ...; Observable<Sandwich> sandwichObservable = Observable.combineLatest( peanutButterObservable, jellyObservable, (pb, j) -> makeSandwich(pb, j)) The problem is that RX waits for the first PeanutButter and the first Jelly to be emitted before emitting the first

Python的IDE之Pycharm的使用

由 你说的曾经没有我的故事 提交于 2021-02-19 04:02:28
Python的IDE之Pycharm的使用 一、为什么用IDE(Python集成开发环境-Pycharm) 到现在为止，我们也是写过代码的人啦，但你有没有发现，每次写代码要新建文件、写完保存时还要选择存放地点，执行时还要切换到命令行调用python解释器，好麻烦呀，能否一气呵成，让我简单的写代码？此时开发工具IDE上场啦，一个好的IDE能帮你大大提升开发效率。 很多语言都有比较流行的开发工具，比如JAVA 的Eclipse， C#，C++的VisualStudio， Python的是啥呢？ Pycharm和Jupyter，最好的两款Python开发IDE。 二、安装Pycharm(老汉推车式) 接下来安装pycharm 1、首先从网站下载pycharm：点击 打开链接 （链接为： http://www.jetbrains.com/pycharm/download/#section=windows），进入之后如下图，根据自己电脑的操作系统进行选择，对于windows系统选择图中红色圈中的区域。 2、在弹出的PyCharm安装欢迎页面中，点击“Next按钮”进入下一步 3、根据你电脑的处理器选择32位或64位，创建桌面快捷方式、关联*.py文件 4、选择开始菜单文件夹，选择Install 5、开始安装 6、安装完成，立刻运行Pycharm 7、选择是否导入开发环境配置文件

Trouble Deploying WAR file. Failed to start component []

由 落爺英雄遲暮 提交于 2021-02-19 04:01:28
问题 I am currently having an issue deploying a WAR file to my Tomcat7 server (Im new to web dev with java). Everything works great in eclipse but when I generate a WAR file and deploy it to the server I get the following error. "Failed to start component []" Below is the log dump. Caused by: org.apache.catalina.LifecycleException: Failed to process either the global, per-host or context-specific context.xml file therefore the [] Context cannot be started. at org.apache.catalina.startup

jlink packages current platform's binaries

由 泪湿孤枕 提交于 2021-02-19 03:58:07
问题 I am trying to build cross-platform archives of an application built using Java 11 and packaged with jlink . For the cross-platform packaging I am basing my build on this answer. I have managed to make my Gradle build download the target platform's JDK and invoke jlink with the appropriate jmods folder, however the target image always includes the binaries and JRE structure of the host platform (in my case Windows, meaning the generated bin folder always includes DLLs and Windows executables)

Strategy in StringConcatFactory

由 你。 提交于 2021-02-19 03:55:09
问题 I have know the invokedynamic instruction. Also I have known the basic process how it implements. But when I arrive the code. I can't understand the code in StringConcatFactory . Can you tell me how the six strategies implements by the source code. Only the default strategy is also done. As a university student, I can't under the source code. private enum Strategy { /** * Bytecode generator, calling into {@link java.lang.StringBuilder}. */ BC_SB, /** * Bytecode generator, calling into {@link

How to choose a value of a HashMap in select Struts2?

由 回眸只為那壹抹淺笑 提交于 2021-02-19 03:54:26
问题 I ran into a problem with Struts2. I have a HashMap<String, Integer> that I use in a form with a select to choose name and corresponding id to that name. HashMap iterates and populates my <select> list with names. I only need an id to pick. How do I pick an id/value instead of a name/key? companyMap is a HashMap , where <String, Integer> or key, value. companyName is a String. <s:select label="Pick the company name" headerKey="-1" headerValue="Select Company name" list="companyMap.keys" name

java error: Exception in thread “main” java.lang.NoClassDefFoundError

由 回眸只為那壹抹淺笑 提交于 2021-02-19 03:53:19
问题 I am a beginner in java and taking the course Algorithm , which is provided by Princeton. In the course, professor asked us to download algs4.jar to a folder and add algs4.jar to the classpath.[1] I followed it step by step, and try to program a HelloWorld like import edu.princeton.cs.algs4.StdOut; public class HelloWorld { public static void main(String args[]) { StdOut.print("Hello World!"); } } However when I compile the file, console reminds me that NPP_EXEC: "java_Compile_Run" NPP_SAVE:

How to fix java.lang.NoSuchMethodError: sun.security.ssl.Handshaker.setApplicationProtocols([Ljava/lang/String;)

由 淺唱寂寞╮ 提交于 2021-02-19 03:52:30
问题 Trying to send an email I got NoSuchMethodError exception when executing transport.connect(...). I chose the same version JDK(1.8.0_251) for my project, module, Glassfish (payara), maven like on this post shows but I keep receiving the same exception. I tried to add the port to the connect method but also the same error. I checked the Gmail account which is sending emails has activated the option to be used by unsecured apps. I also tried to change the method that instance the session to

How to fix java.lang.NoSuchMethodError: sun.security.ssl.Handshaker.setApplicationProtocols([Ljava/lang/String;)

由 徘徊边缘 提交于 2021-02-19 03:52:13
问题 Trying to send an email I got NoSuchMethodError exception when executing transport.connect(...). I chose the same version JDK(1.8.0_251) for my project, module, Glassfish (payara), maven like on this post shows but I keep receiving the same exception. I tried to add the port to the connect method but also the same error. I checked the Gmail account which is sending emails has activated the option to be used by unsecured apps. I also tried to change the method that instance the session to
订阅 java