Google Reflections & Maven - 在 Maven 中找不到数据但在 IDE 中有效

Question

问题

简单处理请求：在java.util包中找到List.class的所有扩展。

这是我使用的来源：

Reflections reflections = new Reflections("java.util");
Set<Class<?>> subtypes = reflections.getSubTypesOf(List.class);

很简单，对吧？

它在 IntelliJ IDEA 和 Eclipse 中都有效，但是当我运行我通过 Maven 进行测试时它不起作用。我尝试使用 org.reflections.util.ConfigurationBuilder 提供的添加 URL 和过滤包名称的方法来添加东西，但没有成功。

有什么建议吗？

我查看了这个 post 但无法正常工作：“Unit test using the Reflections google library fails only when executed by Maven”

代码

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.example</groupId>
  <artifactId>ohno</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <dependencies>
    <dependency>
      <groupId>org.reflections</groupId>
      <artifactId>reflections</artifactId>
      <version>0.9.10</version>
    </dependency>

    <dependency>
      <groupId>org.testng</groupId>
      <artifactId>testng</artifactId>
      <version>6.9.10</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
</project>

Sample.java

package com.example.uhoh;

import org.reflections.Reflections;
import java.util.Set;

public class Sample {

  @SuppressWarnings ("unchecked")
  public static Set<Class<?>> lookup(Class<?> type) {
    Reflections reflections = new Reflections("java.util");
    return (Set<Class<?>>) reflections.getSubTypesOf(type);
  }
}

SampleTest.java

package com.example.uhoh;

import org.testng.Assert;
import org.testng.annotations.Test;
import java.util.List;
import java.util.Set;

@Test
public class SampleTest {

  public void testSample() {
    Set<Class<?>> result = Sample.lookup(List.class);
    Assert.assertNotNull(result, "NULL returned.");
    Assert.assertFalse(result.isEmpty(), "Unable to find any extensions of java.util.List");
  }
}

输出

在IDE工作

Maven 输出

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.example.uhoh.SampleTest
Configuring TestNG with: org.apache.maven.surefire.testng.conf.TestNG652Configurator@4e515669
Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.261 sec <<< FAILURE!
(com.example.uhoh.SampleTest)  Time elapsed: 0.071 sec  <<< FAILURE!
java.lang.AssertionError: Unable to find any extensions of java.util.List expected [false] but found [true]
    at org.testng.Assert.fail(Assert.java:94)
    at org.testng.Assert.failNotEquals(Assert.java:513)
    at org.testng.Assert.assertFalse(Assert.java:63)
    at com.example.uhoh.SampleTest.testSample(SampleTest.java:15)


Results :

Failed tests:   (com.example.uhoh.SampleTest): Unable to find any extensions of java.util.List expected [false] but found [true]

Tests run: 1, Failures: 1, Errors: 0, Skipped: 0

并行错误

代码 public void testSample() { Class[] 数据类型 = { ArrayList.class, LinkedList.class, List.class, 摘要List.class, Collection.class, Map.class、Properties.class };

  Arrays.stream(dataTypes).parallel().forEach(next -> {
    Set<Class<?>> result = Sample.lookup(next);
    Assert.assertNotNull(result, "NULL returned.");
    Assert.assertFalse(result.isEmpty(), "Unable to find any extensions of java.util.List");
  });
}

Maven 输出

java.lang.IllegalStateException: java.lang.IllegalStateException: zip file closed

Answer 1

要解决您的问题，请使用 Reflections 的 ConfigurationBuilder 为包含 class 的 jar 手动设置 URL。这在 IntelliJ 中有效，并且在使用命令行 Maven 调用 Surefire 插件时，mvn test.

Sample.java

public static Set<Class<?>> lookup(Class<?> type) {
    ConfigurationBuilder configurationBuilder = new ConfigurationBuilder();

    // For List.class, this will be a path to rt.jar.
    configurationBuilder.addUrls(ClasspathHelper.forClass(type));

    Reflections reflections = new Reflections(configurationBuilder);
    return (Set<Class<?>>) reflections.getSubTypesOf(type);
}

Answer 2

我刚刚在 Reflections 库（0.9.11 版）中遇到了同样的问题，只是在从 Maven 构建执行单元测试时。对我的 Surefire 插件的一个简单的 POM 文件更改为我解决了这个问题。

        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            <version>2.21.0</version>
            <configuration>
                <useSystemClassLoader>false</useSystemClassLoader>
            </configuration>
        </plugin>
        <plugin>
            <artifactId>maven-failsafe-plugin</artifactId>
            <version>2.21.0</version>
            <configuration>
                <useSystemClassLoader>false</useSystemClassLoader>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>integration-test</goal>
                        <goal>verify</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

<useSystemClassLoader> 配置参数默认为 'true'。强制它 'false' 似乎解决了我单元测试中的类加载器问题。

Google Reflections & Maven - 在 Maven 中找不到数据但在 IDE 中有效

Google Reflections & Maven - not finding data in Maven but works in IDE

maven-3

maven

reflections

问题

代码

输出

并行错误