Merge pull request #1013 from FreaxLin/Restore_the_already_crawled_example

提交可恢复爬取内容例子

webmagic-samples/pom.xml

@@ -24,6 +24,26 @@
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.mapdb</groupId>
+            <artifactId>mapdb</artifactId>
+            <version>3.0.7</version>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-core</artifactId>
+            <version>2.9.5</version>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-annotations</artifactId>
+            <version>2.9.5</version>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.9.5</version>
+        </dependency>
     </dependencies>
 
 </project>

webmagic-samples/src/main/java/us/codecraft/webmagic/recover/DuplicateStorageRemover.java

@@ -0,0 +1,82 @@
+package us.codecraft.webmagic.recover;
+
+import com.google.common.base.Charsets;
+import com.google.common.hash.BloomFilter;
+import com.google.common.hash.Funnels;
+import org.mapdb.DB;
+import org.mapdb.DBMaker;
+import org.mapdb.IndexTreeList;
+import org.mapdb.Serializer;
+import us.codecraft.webmagic.Request;
+import us.codecraft.webmagic.Task;
+import us.codecraft.webmagic.scheduler.component.DuplicateRemover;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * @author ：linweisen
+ * @date ：Created in 2021/4/9 14:46
+ * @description：${description}
+ * @modified By：
+ * @version: 1.0
+ */
+public class DuplicateStorageRemover implements DuplicateRemover {
+
+    private DB db;
+
+    private static String DATABASE_NAME = "duplicate";
+
+    private IndexTreeList<String> urlDuplicateQueue;
+
+    private BloomFilter<CharSequence> bloomFilter;
+
+    private AtomicInteger counter;
+
+    public DuplicateStorageRemover(String path) {
+
+        String duplicatStoragePath = path;
+
+        DB db = DBMaker.fileDB(duplicatStoragePath)
+                .fileMmapEnableIfSupported()
+                .fileMmapPreclearDisable()
+                .cleanerHackEnable()
+                .closeOnJvmShutdown()
+                .transactionEnable()
+                .concurrencyScale(128)
+                .make();
+        this.db = db;
+
+        this.urlDuplicateQueue = db.indexTreeList(DATABASE_NAME, Serializer.STRING).createOrOpen();
+
+        counter = new AtomicInteger(this.urlDuplicateQueue.size());
+        this.bloomFilter = BloomFilter.create(Funnels.stringFunnel(Charsets.UTF_8), 200000, 1E-7);
+        for (String url : this.urlDuplicateQueue){
+            bloomFilter.put(url);
+        }
+
+    }
+
+    @Override
+    public boolean isDuplicate(Request request, Task task) {
+        String url = request.getUrl();
+        boolean isDuplicate = bloomFilter.mightContain(url);
+        if (!isDuplicate) {
+            bloomFilter.put(url);
+            urlDuplicateQueue.add(url);
+            this.db.commit();
+            counter.incrementAndGet();
+        }
+        return isDuplicate;
+    }
+
+    @Override
+    public void resetDuplicateCheck(Task task) {
+        this.bloomFilter = BloomFilter.create(Funnels.stringFunnel(Charsets.UTF_8), 200000, 1E-7);
+        this.urlDuplicateQueue.clear();
+    }
+
+    @Override
+    public int getTotalRequestsCount(Task task) {
+        return counter.get();
+    }
+}

webmagic-samples/src/main/java/us/codecraft/webmagic/recover/MmapQueueScheduler.java

@@ -0,0 +1,89 @@
+package us.codecraft.webmagic.recover;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.commons.lang3.StringUtils;
+import org.mapdb.DB;
+import org.mapdb.DBMaker;
+import org.mapdb.IndexTreeList;
+import org.mapdb.Serializer;
+import us.codecraft.webmagic.Request;
+import us.codecraft.webmagic.Task;
+import us.codecraft.webmagic.scheduler.DuplicateRemovedScheduler;
+import us.codecraft.webmagic.scheduler.component.DuplicateRemover;
+
+import java.io.IOException;
+
+/**
+ * @author ：linweisen
+ * @date ：Created in 2021/4/9 14:38
+ * @description：${description}
+ * @modified By：
+ * @version: 1.0
+ */
+public class MmapQueueScheduler extends DuplicateRemovedScheduler {
+
+    private DB db;
+
+    private static String DATABASE_NAME = "queue";
+
+    private IndexTreeList<String> queue;
+
+    private static ObjectMapper mapper;
+
+    public MmapQueueScheduler(DuplicateRemover duplicateRemover, String path) {
+        super.setDuplicateRemover(duplicateRemover);
+
+        String queuePath = path;
+
+        DB db = DBMaker.fileDB(queuePath)
+                .fileMmapEnableIfSupported()
+                .fileMmapPreclearDisable()
+                .cleanerHackEnable()
+                .closeOnJvmShutdown()
+                .transactionEnable()
+                .concurrencyScale(128)
+                .make();
+        this.db = db;
+        this.mapper = new ObjectMapper();
+        this.queue = db.indexTreeList(MmapQueueScheduler.DATABASE_NAME, Serializer.STRING).createOrOpen();
+    }
+
+    @Override
+    public Request poll(Task task) {
+        if (this.queue.size() > 0){
+            String s = queue.remove(0);
+            return fromJson(s, Request.class);
+        }else{
+            return null;
+        }
+
+    }
+
+    @Override
+    public void pushWhenNoDuplicate(Request request, Task task) {
+        queue.add(toJson(request));
+        this.db.commit();
+    }
+
+    public String toJson(Object object) {
+        try {
+            return mapper.writeValueAsString(object);
+        } catch (IOException e) {
+            logger.warn("write to json string error:" + object, e);
+            return null;
+        }
+    }
+
+    public <T> T fromJson(String jsonString, Class<T> clazz) {
+        if (StringUtils.isEmpty(jsonString)) {
+            return null;
+        }
+        try {
+            return mapper.readValue(jsonString, clazz);
+        } catch (IOException e) {
+            logger.warn("parse json string error:" + jsonString, e);
+            return null;
+        }
+    }
+
+}

webmagic-samples/src/main/java/us/codecraft/webmagic/recover/RecoverSample.java

@@ -0,0 +1,22 @@
+package us.codecraft.webmagic.recover;
+
+
+import us.codecraft.webmagic.Spider;
+import us.codecraft.webmagic.samples.SinaBlogProcessor;
+import us.codecraft.webmagic.scheduler.component.DuplicateRemover;
+
+/**
+ * @author code4crafter@gmail.com <br>
+ */
+public class RecoverSample {
+
+    public static void main(String[] args) {
+        String storage = "queue";
+        String duplicate = "duplicate";
+        Spider spider = new Spider(new SinaBlogProcessor());
+        DuplicateRemover remover = new DuplicateStorageRemover(duplicate);
+        spider.setScheduler(new MmapQueueScheduler(remover, storage));
+        spider.addUrl("http://blog.sina.com.cn/s/articlelist_1487828712_0_1.html")
+                .run();
+    }
+}