annotations

问题 To create a type annotation that is applicable in type contexts, there is no way other than meta-annotating the annotation type with @Target(ElementType.TYPE_USE) . However, this annotation also becomes applicable in declaration contexts due to the bad decision of the Java designers. According to the Java SE documentation, it reads: The constant TYPE_USE corresponds to the type contexts in JLS 4.11, as well as to two declaration contexts: type declarations (including annotation type

问题 I want to pass my config properties from YAML file to annotations value like this: @SendTo(value = "${config.ws.topic}") , but get an error Could not resolve placeholder config.ws.topic etc .. My Code: @MessageMapping("/chat.register") @SendTo("${config.websocket.topic}") public Message addUser(@Payload Message message, SimpMessageHeaderAccessor headerAccessor) { headerAccessor.getSessionAttributes().put("username", message.getSender()); return message; } Prop-es file: server: address: 127.0

问题 I have en error with java annotation on scala enums. This scala bug seems to be fixed, but Inteliij Idea shows an error. So how I can ensure that intellij Idea scala plugin uses actual scala version? 回答1: You can check the Scala compiler and language level of your project under your project options from File > Project Structure... > Modules > Scala 来源： https://stackoverflow.com/questions/24363409/what-scala-version-intellij-idea-scala-plugin-uses

问题 I have en error with java annotation on scala enums. This scala bug seems to be fixed, but Inteliij Idea shows an error. So how I can ensure that intellij Idea scala plugin uses actual scala version? 回答1: You can check the Scala compiler and language level of your project under your project options from File > Project Structure... > Modules > Scala 来源： https://stackoverflow.com/questions/24363409/what-scala-version-intellij-idea-scala-plugin-uses

问题 I got this chart in line chart of google api. Here i'm trying to display the point value in above the point. so i'm using annotation. Here how to remove annotation tick mark in between the points(23 & 2008, 145 & 2009...) in google api chart. <script type="text/javascript"> google.load("visualization", "1", {packages: ["corechart"]}); google.setOnLoadCallback(drawChart); function drawChart() { var data = new google.visualization.DataTable(); data.addColumn('string', 'Year'); data.addColumn(

问题 I got this chart in line chart of google api. Here i'm trying to display the point value in above the point. so i'm using annotation. Here how to remove annotation tick mark in between the points(23 & 2008, 145 & 2009...) in google api chart. <script type="text/javascript"> google.load("visualization", "1", {packages: ["corechart"]}); google.setOnLoadCallback(drawChart); function drawChart() { var data = new google.visualization.DataTable(); data.addColumn('string', 'Year'); data.addColumn(

问题 I'm writing a custom API using Reflection to save Objects to file. I have the following class structure: @Constructor public XYZPOJO(@Key(key = "word") String word, @Key(key = "variations") ArrayList<String> varList) { this.word = word; this.varList = varList; } String word; ArrayList<String> varList = new ArrayList<String>(); @Key(key = "word") public String getWord() { return word; } @Key(key = "variations") public ArrayList<String> getVarList() { return varList; } When saving Object to

问题 I didn't use @Param annotation at first, this is my mapper.java public void changeUserAuth(Integer userId,int identity); , and this is my mapper.xml <update id="changeUserAuth"> update user <set> <if test="identity != 0">identity = #{identity}</if> </set> <where> <if test="userId != 0">userId = #{userId}</if> </where> </update> then it works correctly!I continue to write like this, as follows: //this's mapper.java public void updateUserStatus(Integer userId); <!--this is mapper.xml> <update

问题 In C#, when specifying how an attribute class should be used, there is a GenericParameter value in the System.AttributeTargets enum. How can we apply such an attribute, what is the syntax ? [System.AttributeUsage(System.AttributeTargets public sealed class MyAnnotationAttribute : System.Attribute { public string Param { get; private set; } public MyAnnotationAttribute(string param) { Param = param; } } Same question goes for other exotic attribute targets, like System.AttributeTargets.Module

问题 I'm currently trying to configure Spring Boot (using Java Annotations and ComponentScan ) for the following scenario: Scenario There's an interface MyService . I want to provide a default implementation for MyService , let's call it MyDefaultService . If the component scan detects no other implementation for MyService , Spring should instantiate MyDefaultService as a "fallback". If there is a different implementation of MyService present, let's say MyCustomService , then that bean should