class switch1 { public static void main(String args[]) { int a = 10; switch(a) { default: System.out.println("Default"); case -1: System.out.println("-1"); } } } I understand that this program will execute both "default" and "case -1" statements as break is not specified after the matching condition (in this c
class switch1 { public static void main(String args[]) { int a = 10; switch(a) { default: System.out.println("Default"); case -1: System.out.println("-1"); } } } 我知道这个程序会执行“default”和“case -1”语句，因为在匹配条件之后没有指定break（在这种情况下，在“default”之后）。 但是我不明白的是 a）为什么在switch语句中需要break
Example from Oracle public class SwitchDemo { public static void main(String[] args) { int month = 8; String monthString; switch (month) { case 1: monthString = "January"; break; case 2: monthString = "February"; break; case 3: monthString = "March"; break;
来自Oracle的示例 public class SwitchDemo { public static void main(String[] args) { int month = 8; String monthString; switch (month) { case 1: monthString = "January"; break; case 2: monthString = "February"; break; case 3: monthString = "March"; break;
I have some switch statement as shown below. Notice there is no break. Findbugs is reporting error on the second case statement only. The error is : Switch statement found where one case falls through to the next case. switch(x) { case 0: // code case 1: // code case 2: // code } Findbugs is flagging up that falling through from one case to the next is
我有一些switch语句如下所示。 注意没有休息。 Findbugs仅在第二个case语句中报告错误。 错误是：在一种情况下发生的切换语句到达下一种情况。 switch(x) { case 0: // code case 1: // code case 2: // code } 如果在第一个代码中有任何代码（尽管有时它可以用来产生良好效果），Findbugs正在标记从一种case到另一种case下降通常不是一个好主意。 因此，当它看到第二个case并且没
I programmed a game. I used switch case to implement a state machine. The problem is that in case ZIEHEN_SP the break statement doesn't work. When I debug it, the compiler just step over the break statement and goes to the next case ZIEHEN_BA. I commented the part where the compiler ignores the break statement. Why? import java.util.*; import java.util.Scanner; import java.io.*; cla
我编了一个游戏。 我用开关盒来实现状态机。 问题是，如果ZIEHEN_SP break语句不起作用。 当我调试它时，编译器只是跨越break语句并转到下一个案例ZIEHEN_BA。 我评论了编译器忽略break语句的部分。 为什么？ import java.util.*; import java.util.Scanner; import java.io.*; class BlackJack2 { static int chips = 100; static int einsatz = 0; enum State { INIT, EINSATZ,ZIEHEN_SP, ZIEHEN_BA}
My switch-case statement works perfectly fine yesterday. But when I run the code earlier this morning eclipse gave me an error underlining the case statements in color red and says: case expressions must be constant expression, it is constant I don't know what happened. Here's my code below: public void onClick(View src) { switch(src.getId()) { case R.id.playbtn:
我的switch-case语句昨天完全正常。 但是当我今天早上运行代码时，eclipse给了我一个以红色表示的case语句的错误，并且说：case表达式必须是常量表达式，它是常量，我不知道发生了什么。 以下是我的代码： public void onClick(View src) { switch(src.getId()) { case R.id.playbtn: checkwificonnection(); break; case R.id.stopbtn: Log.d(TAG, "onClic
I registered my interceptor with the following code @EnableWebMvc public class WebMvcConfig extends WebMvcConfigurerAdapter { ... @Override public void addInterceptors(InterceptorRegistry registry) { registry.addInterceptor( myInterceptor() ); } ... } Here the interceptor definition public class MyInterceptorimplements HandlerInterceptor { @Override public boolean preHandle(HttpServl
我用下面的代码注册了我的拦截器 @EnableWebMvc public class WebMvcConfig extends WebMvcConfigurerAdapter { ... @Override public void addInterceptors(InterceptorRegistry registry) { registry.addInterceptor( myInterceptor() ); } ... } 这里是拦截器的定义 public class MyInterceptorimplements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResp
I'm using Eclipse kepler to make a maven 2 or 3 project. I used the "webapp" archetype to start with a clean empty project, and I followed some simple helloworld tutorials. However, I noticed that in eclipse my src folder is shown twice, as seen in the picture below: This is very undesirable, it takes up additional space and they are not very well synchronized, for example the s
我使用Eclipse kepler来制作maven 2或3项目。 我使用“webapp”原型来开始一个干净的空项目，并且我遵循了一些简单的helloworld教程。 但是，我注意到在eclipse中我的src文件夹显示了两次，如下图所示： 这是非常不可取的，它占用了额外的空间，并且它们并没有很好地同步，例如底部的src包含"webapp"文件夹，但顶部的src没有。 这种双重结构的处理是什么？ 我的同事们，使用较旧版本的eclipse，没有看到"java
I was given a snippet of code to decipher, explain and offer any recommendations for improvement. I was told it works and we can't run the code to test it. I pretty much understand it but just need to run it by someone to make sure what I do understand about it is correct and please get any help with explaining what I don't understand.I have been doing a ton of research and still have s
我得到了一小段代码来解密，解释并提供任何改进建议。 我被告知它的工作原理，我们不能运行代码来测试它。 我非常了解它，但只是需要由某人来运行它，以确保我对它的理解是正确的，请帮助解释我不明白的内容。我已经做了大量的研究，并且仍然有一些的问题。 该代码正在实现用于读取仅使用乘法和加法的后缀表达式。 然后在将结果保存到堆栈的同时评估表达式。 然后打印出结果。 操作数被压入堆栈，然后当它读取一个操作符
Suppose i have class ie private class Student { private Integer x = 1000; public Integer getX() { return x; } public void setX(Integer x) { this.x = x; } } Now suppose json is "{x:12}" and doing deserialization then the x will have the value is 12 . But if the json is "{}" then the value of x = 1000 (get
假设我有类即ie private class Student { private Integer x = 1000; public Integer getX() { return x; } public void setX(Integer x) { this.x = x; } } 现在假设json是"{x:12}"并进行反序列化，那么x的值就是12 。 但是，如果json是"{}"那么x = 1000的值（get是来自类中声明的属性的默认值）。 现在，如果json是"{x:
I'm going through the OCA Java SE 7 study guide and am going through packages. However, I'm inputting the same code in Eclipse, found in the book but I'm getting this error. The error is Exception in thread "main" java.lang.NullPointerException at com.ocaj.exam.tutorial.MainClass.main(MainClass.java:12) Here is my code... package com.ocaj.exam.tutorial; //Package
我正在阅读OCA Java SE 7学习指南，并正在审阅包。 不过，我在Eclipse中输入了相同的代码，但是我遇到了这个错误。 错误是 线程“main”中的异常java.lang.NullPointerException at com.ocaj.exam.tutorial.MainClass.main（MainClass.java:12） 这是我的代码... package com.ocaj.exam.tutorial; //Package statement //Imports class ArrayList from the java.util package import java.util.ArrayList; //Imports al