错误：java.lang.NoClassDefFoundError：org / apache / commons / collections / map / LRUMap

Question

我正在尝试在程序中实现简单的缓存。因此，为此，我尝试在Java中使用Restful Web Services。我不使用spring或任何类型的框架，只是基于Maven的项目。

我的代码是：

的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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.ashwin</groupId>
    <artifactId>JaxMaven11</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>JaxMaven11</name>

    <properties>
        <endorsed.dir>${project.build.directory}/endorsed</endorsed.dir>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-web-api</artifactId>
            <version>7.0</version>
            <scope>provided</scope>
        </dependency>

<!-- https://mvnrepository.com/artifact/commons-collections/commons-collections -->
<dependency>
    <groupId>commons-collections</groupId>
    <artifactId>commons-collections</artifactId>
    <version>3.2.1</version>
</dependency>
<dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.1.1</version>
</dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                    <compilerArguments>
                        <endorseddirs>${endorsed.dir}</endorseddirs>
                    </compilerArguments>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.3</version>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>2.6</version>
                <executions>
                    <execution>
                        <phase>validate</phase>
                        <goals>
                            <goal>copy</goal>
                        </goals>
                        <configuration>
                            <outputDirectory>${endorsed.dir}</outputDirectory>
                            <silent>true</silent>
                            <artifactItems>
                                <artifactItem>
                                    <groupId>javax</groupId>
                                    <artifactId>javaee-endorsed-api</artifactId>
                                    <version>7.0</version>
                                    <type>jar</type>
                                </artifactItem>
                            </artifactItems>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

用于影响缓存的API：

package com.ashwin.jaxmaven11;

import com.ashwin.jaxmaven11.cache.CrunchifyInMemoryCacheTest;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.UriInfo;
import javax.ws.rs.Produces;
import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PUT;
import javax.ws.rs.core.MediaType;

/**
 * REST Web Service
 *
 * @author AshwinPC
 */
@Path(value="contact")
public class ContactAPI {


    @GET
    public String index(){

         CrunchifyInMemoryCacheTest crunchifyCache = new CrunchifyInMemoryCacheTest();

        System.out.println("\n\n==========Test1: crunchifyTestAddRemoveObjects ==========");
        crunchifyCache.crunchifyTestAddRemoveObjects();
        System.out.println("\n\n==========Test2: crunchifyTestExpiredCacheObjects ==========");
        crunchifyCache.crunchifyTestAddRemoveObjects();
        System.out.println("\n\n==========Test3: crunchifyTestObjectsCleanupTime ==========");
       crunchifyCache.crunchifyTestAddRemoveObjects();

        return "hello";
    }

}

CrunchifyMemoryClass.java

package com.ashwin.jaxmaven11.cache;
import java.util.ArrayList;
import org.apache.commons.collections.MapIterator;
import org.apache.commons.collections.map.LRUMap;


public class CrunchifyInMemoryCache<K, T> {
       private long timeToLive;
    private LRUMap crunchifyCacheMap;

    protected class CrunchifyCacheObject {
        public long lastAccessed = System.currentTimeMillis();
        public T value;

        protected CrunchifyCacheObject(T value) {
            this.value = value;
        }
    }

    public CrunchifyInMemoryCache(long crunchifyTimeToLive, final long crunchifyTimerInterval, int maxItems) {
        this.timeToLive = crunchifyTimeToLive * 1000;

        crunchifyCacheMap = new LRUMap(maxItems);

        if (timeToLive > 0 && crunchifyTimerInterval > 0) {

            Thread t = new Thread(new Runnable() {
                public void run() {
                    while (true) {
                        try {
                            Thread.sleep(crunchifyTimerInterval * 1000);
                        } catch (InterruptedException ex) {
                        }
                        cleanup();
                    }
                }
            });

            t.setDaemon(true);
            t.start();
        }
    }

    public void put(K key, T value) {
        synchronized (crunchifyCacheMap) {
            crunchifyCacheMap.put(key, new CrunchifyCacheObject(value));
        }
    }

    @SuppressWarnings("unchecked")
    public T get(K key) {
        synchronized (crunchifyCacheMap) {
            CrunchifyCacheObject c = (CrunchifyCacheObject) crunchifyCacheMap.get(key);

            if (c == null)
                return null;
            else {
                c.lastAccessed = System.currentTimeMillis();
                return c.value;
            }
        }
    }

    public void remove(K key) {
        synchronized (crunchifyCacheMap) {
            crunchifyCacheMap.remove(key);
        }
    }

    public int size() {
        synchronized (crunchifyCacheMap) {
            return crunchifyCacheMap.size();
        }
    }

    @SuppressWarnings("unchecked")
    public void cleanup() {

        long now = System.currentTimeMillis();
        ArrayList<K> deleteKey = null;

        synchronized (crunchifyCacheMap) {
            MapIterator itr = crunchifyCacheMap.mapIterator();

            deleteKey = new ArrayList<K>((crunchifyCacheMap.size() / 2) + 1);
            K key = null;
            CrunchifyCacheObject c = null;

            while (itr.hasNext()) {
                key = (K) itr.next();
                c = (CrunchifyCacheObject) itr.getValue();

                if (c != null && (now > (timeToLive + c.lastAccessed))) {
                    deleteKey.add(key);
                }
            }
        }

        for (K key : deleteKey) {
            synchronized (crunchifyCacheMap) {
                crunchifyCacheMap.remove(key);
            }

            Thread.yield();
        }
    }
}

CruncifyInmemeoryTest.java

package com.ashwin.jaxmaven11.cache;
public class CrunchifyInMemoryCacheTest {


    public void crunchifyTestAddRemoveObjects() {

        // Test with crunchifyTimeToLive = 200 seconds
        // crunchifyTimerInterval = 500 seconds
        // maxItems = 6
        CrunchifyInMemoryCache<String, String> cache = new CrunchifyInMemoryCache<String, String>(200, 500, 6);

        cache.put("eBay", "eBay");
        cache.put("Paypal", "Paypal");
        cache.put("Google", "Google");
        cache.put("Microsoft", "Microsoft");
        cache.put("IBM", "IBM");
        cache.put("Facebook", "Facebook");

        System.out.println("6 Cache Object Added.. cache.size(): " + cache.size());
        cache.remove("IBM");
        System.out.println("One object removed.. cache.size(): " + cache.size());

        cache.put("Twitter", "Twitter");
        cache.put("SAP", "SAP");
        System.out.println("Two objects Added but reached maxItems.. cache.size(): " + cache.size());

    }

    private void crunchifyTestExpiredCacheObjects() throws InterruptedException {

        // Test with crunchifyTimeToLive = 1 second
        // crunchifyTimerInterval = 1 second
        // maxItems = 10
        CrunchifyInMemoryCache<String, String> cache = new CrunchifyInMemoryCache<String, String>(1, 1, 10);

        cache.put("eBay", "eBay");
        cache.put("Paypal", "Paypal");
        // Adding 3 seconds sleep.. Both above objects will be removed from
        // Cache because of timeToLiveInSeconds value
        Thread.sleep(3000);

        System.out.println("Two objects are added but reached timeToLive. cache.size(): " + cache.size());

    }

    private void crunchifyTestObjectsCleanupTime() throws InterruptedException {
        int size = 500000;

        // Test with timeToLiveInSeconds = 100 seconds
        // timerIntervalInSeconds = 100 seconds
        // maxItems = 500000

        CrunchifyInMemoryCache<String, String> cache = new CrunchifyInMemoryCache<String, String>(100, 100, 500000);

        for (int i = 0; i < size; i++) {
            String value = Integer.toString(i);
            cache.put(value, value);
        }

        Thread.sleep(200);

        long start = System.currentTimeMillis();
        cache.cleanup();
        double finish = (double) (System.currentTimeMillis() - start) / 1000.0;

        System.out.println("Cleanup times for " + size + " objects are " + finish + " s");

    }
}

我尝试访问URL： http：// localhost：8080 / JaxMaven11 / api / contact，但出现以下错误：

Answer 1

我让您的项目在我的环境中正常工作（或至少在Chrome上显示“ hello”）

我以为我从来没有遇到过505错误，甚至在我修改之前也没有。 无论如何，我添加了以下类来配置servlet（否则我根本没有得到响应）：

Application.java

package com.ashwin.jaxmaven11;

import javax.ws.rs.ApplicationPath;

@ApplicationPath("/api")
public class Application extends javax.ws.rs.core.Application {
}

然后，我在方法中添加了@Produce批注。 没有它，我看不到浏览器上显示的“ hello”，但显示的是ERR_INVALID_SIGNED_EXCHANGE。 （尽管如此，它与Postman一起正常工作）

ContactAPI.java

[...]
@Path("/contact")
public class ContactAPI  {

    @GET
    @Produces("text/html")
    public String index(){
        [...]
    }

}

PS：我部署在Wildfly 11上，并使用Java 1.7进行编译。