Java 包 org.apache.commons 不存在
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package org.apache.commons does not exist
提问by Galia
I'd love to use EnumeratedIntegerDistribution()from org.apache.commons.math3.distribution, to get discrete probabilities distribution
我很想使用EnumeratedIntegerDistribution()fromorg.apache.commons.math3.distribution来获得离散概率分布
int[] nums_to_generate = new int[] { -1, 1, 0 };
double[] discrete_probabilities = new double[] { 0.4, 0.4, 0.2 };
I'm working wiht jdk7 , on windows Xp, running from Command Line
我正在使用 jdk7 ，在 Windows Xp 上，从命令行运行
I do:
我愿意：
add to my source file
import org.apache.commons.math3;- download commons-math3-3.2 and unpackage it to my current folder
compile my source with the classpath: (either)
javac -cp ./commons-math3-3.2/commons-math3-3.2.jar:. ConflictsAnimation.java javac -cp commons-math3-3.2/commons-math3-3.2.jar ConflictsAnimation.java
添加到我的源文件
import org.apache.commons.math3;- 下载 commons-math3-3.2 并将其解压缩到我的当前文件夹
使用类路径编译我的源代码：（或者）
javac -cp ./commons-math3-3.2/commons-math3-3.2.jar:. ConflictsAnimation.java javac -cp commons-math3-3.2/commons-math3-3.2.jar ConflictsAnimation.java
Still I've got a mysterious
我仍然有一个神秘的
"error: package org.apache.commons does not exist"
Who knows what happens ? I really need a help.
谁知道会发生什么？我真的需要帮助。
Note:
笔记：
compilation (and run) is OK without the classpath and without the import of "apache" and call to numeratedIntegerDistribution().
compilation with the classpath and without the "appache"s give nonsense errors.
编译（和运行）在没有类路径和没有导入“apache”和调用 numeratedIntegerDistribution() 的情况下是可以的。
使用类路径而不使用“appache”进行编译会产生无意义的错误。
Thanks a lot in advance for your great skills, the programmers!
非常感谢您的出色技能，程序员！
Here is short demonstration:
这是简短的演示：
import java.lang.Math.*;
import org.apache.commons.math3;
public class CheckMe {
public CheckMe() {
System.out.println("let us check it out");
System.out.println(generate_rand_distribution (10));
}
private static int[] generate_rand_distribution (int count){
int[] nums_to_generate = new int[] { -1, 1, 0 };
double[] discrete_probabilities = new double[] { 0.4, 0.4, 0.2 };
int[] samples = null;
EnumeratedIntegerDistribution distribution =
new EnumeratedIntegerDistribution(nums_to_generate, discrete_probabilities);
samples = distribution.sample (count);
return (samples);
}
public static void main (String args[]) {
System.out.println("Main: ");
CheckMe animation = new CheckMe();
}
}
回答by Jon Skeet
This is the problem:
这就是问题：
import org.apache.commons.math3;
That's trying to import a package- you can't do that. You have to either use a wildcard import:
那是试图导入一个包- 你不能那样做。您必须使用通配符导入：
import org.apache.commons.math3.*;
or import a specific type:
或导入特定类型：
import org.apache.commons.math3.SomeTypeHere;
In your case it sounds like you actually want:
在您的情况下，听起来您确实想要：
import org.apache.commons.math3.distribution.EnumeratedIntegerDistribution;
I've tried a sample class with justthat import and the jar file downloaded from Apache, and it works fine.
我已经尝试了一个示例类，其中仅包含该导入和从 Apache 下载的 jar 文件，并且运行良好。
