diff --git a/src/main/java/com/ilummc/eagletdl/AlreadyStartException.java b/src/main/java/com/ilummc/eagletdl/AlreadyStartException.java
new file mode 100644
index 0000000..13919a0
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/AlreadyStartException.java
@@ -0,0 +1,4 @@
+package com.ilummc.eagletdl;
+
+public class AlreadyStartException extends RuntimeException {
+}
diff --git a/src/main/java/com/ilummc/eagletdl/CompleteEvent.java b/src/main/java/com/ilummc/eagletdl/CompleteEvent.java
new file mode 100644
index 0000000..839625b
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/CompleteEvent.java
@@ -0,0 +1,19 @@
+package com.ilummc.eagletdl;
+
+public class CompleteEvent {
+    private EagletTask task;
+    private boolean success;
+
+    CompleteEvent(EagletTask task, boolean success) {
+        this.task = task;
+        this.success = success;
+    }
+
+    public boolean isSuccess() {
+        return success;
+    }
+
+    public EagletTask getTask() {
+        return task;
+    }
+}
diff --git a/src/main/java/com/ilummc/eagletdl/ConnectedEvent.java b/src/main/java/com/ilummc/eagletdl/ConnectedEvent.java
new file mode 100644
index 0000000..5299f27
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/ConnectedEvent.java
@@ -0,0 +1,27 @@
+package com.ilummc.eagletdl;
+
+public class ConnectedEvent {
+
+    private long contentLength;
+    private EagletTask task;
+
+    public ConnectedEvent(long length, EagletTask task) {
+        this.contentLength = length;
+        this.task = task;
+    }
+
+    /**
+     * Get the length of the download task.
+     * <p>
+     * If the length is -1, this task cannot be downloaded in multiple threads.
+     *
+     * @return length
+     */
+    public long getContentLength() {
+        return contentLength;
+    }
+
+    public EagletTask getTask() {
+        return task;
+    }
+}
diff --git a/src/main/java/com/ilummc/eagletdl/DoNotSupportMultipleThreadException.java b/src/main/java/com/ilummc/eagletdl/DoNotSupportMultipleThreadException.java
new file mode 100644
index 0000000..0c59692
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/DoNotSupportMultipleThreadException.java
@@ -0,0 +1,4 @@
+package com.ilummc.eagletdl;
+
+public class DoNotSupportMultipleThreadException extends RuntimeException {
+}
diff --git a/src/main/java/com/ilummc/eagletdl/Eaglet.java b/src/main/java/com/ilummc/eagletdl/Eaglet.java
new file mode 100644
index 0000000..7e000b3
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/Eaglet.java
@@ -0,0 +1,22 @@
+package com.ilummc.eagletdl;
+
+/**
+ * Test class
+ */
+public class Eaglet {
+
+    public static void main(String[] args) {
+        //new EagletTask().url("http://sgp-ping.vultr.com/vultr.com.100MB.bin")
+        new EagletTask().url("https://gitee.com/bkm016/TabooLibCloud/raw/master/TabooMenu/TabooMenu.jar")
+                .file("F:\\test.dl")
+                .setThreads(1)
+                .readTimeout(1000)
+                .connectionTimeout(1000)
+                .maxRetry(30)
+                .setOnConnected(event -> System.out.println(event.getContentLength()))
+                .setOnProgress(event -> System.out.println(event.getSpeedFormatted() + " " + event.getPercentageFormatted()))
+                .setOnComplete(event -> System.out.println("Complete"))
+                .start();
+    }
+
+}
diff --git a/src/main/java/com/ilummc/eagletdl/EagletHandler.java b/src/main/java/com/ilummc/eagletdl/EagletHandler.java
new file mode 100644
index 0000000..ef63e4a
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/EagletHandler.java
@@ -0,0 +1,8 @@
+package com.ilummc.eagletdl;
+
+@FunctionalInterface
+public interface EagletHandler<T> {
+
+    void handle(T event) ;
+
+}
diff --git a/src/main/java/com/ilummc/eagletdl/EagletTask.java b/src/main/java/com/ilummc/eagletdl/EagletTask.java
new file mode 100644
index 0000000..fb85bdb
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/EagletTask.java
@@ -0,0 +1,460 @@
+package com.ilummc.eagletdl;
+
+import java.io.File;
+import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
+import java.net.Proxy;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.ReentrantLock;
+
+public class EagletTask {
+
+    private ReentrantLock lock = new ReentrantLock();
+
+    Map<String, String> httpHeader = new ConcurrentHashMap<>();
+
+    private URL url;
+
+    EagletHandler<ErrorEvent> onError = event -> event.getException().printStackTrace();
+
+    private EagletHandler<StartEvent> onStart;
+
+    private EagletHandler<CompleteEvent> onComplete;
+
+    private EagletHandler<ConnectedEvent> onConnected;
+
+    private EagletHandler<ProgressEvent> onProgress;
+
+    private Proxy proxy;
+
+    private String md5, sha1, sha256;
+
+    String requestMethod = "GET";
+
+    private int threadAmount = 1;
+
+    int connectionTimeout = 7000;
+    int readTimeout = 7000;
+    int maxRetry = 3;
+
+    private File dest;
+
+    private transient boolean running = false;
+    private transient long contentLength, maxBlockingTime = 7000;
+    private transient ExecutorService executorService;
+    private transient Thread monitor;
+
+    public EagletTask() {
+    }
+
+    /**
+     * Stop this task forcefully, and the target file will not be removed.
+     */
+    public void stop() {
+        executorService.shutdownNow();
+        monitor.interrupt();
+    }
+
+    /**
+     * Start the download file
+     * <p>
+     * 开始下载文件
+     */
+    public EagletTask start() {
+        // create thread pool for download
+        executorService = Executors.newFixedThreadPool(threadAmount);
+        // check if is already running
+        if (running) throw new AlreadyStartException();
+        // start the monitor thread
+        monitor = new Thread(() -> {
+            lock.lock();
+            // fire a new start event
+            if (onStart != null) onStart.handle(new StartEvent(this));
+            try {
+                // create the target file
+                if (!dest.exists()) dest.createNewFile();
+                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+                // set the connection properties
+                httpHeader.forEach(connection::addRequestProperty);
+                connection.setRequestMethod(requestMethod);
+                connection.setConnectTimeout(30000);
+                connection.setReadTimeout(30000);
+                connection.connect();
+                contentLength = connection.getContentLengthLong();
+                // fire a new connected event
+                // contains connection properties
+                if (onConnected != null) onConnected.handle(new ConnectedEvent(contentLength, this));
+                // if this is an unknown length task
+                if (contentLength == -1 || threadAmount == 1) {
+                    // pass the connection instance to this new thread
+                    SingleThreadDownload download = new SingleThreadDownload(connection, dest, this);
+                    executorService.execute(download);
+                    long last = 0;
+                    while (true) {
+                        Thread.sleep(1000);
+                        // check the progress
+                        long progress = download.getCurrentProgress();
+                        // fire a new progress event
+                        if (onProgress != null)
+                            onProgress.handle(new ProgressEvent(progress - last, this,
+                                    ((double) progress) / Math.max((double) contentLength, 0D)));
+                        last = progress;
+                        // check complete
+                        if (last == contentLength || download.isComplete()) {
+                            break;
+                        }
+                    }
+                    // close the thread pool, release resources
+                    executorService.shutdown();
+                    // change the running flag to false
+                    running = false;
+                } else {
+                    List<SplitDownload> splitDownloads = new ArrayList<>();
+                    // Assign download task length
+                    long blockSize = contentLength / threadAmount;
+                    for (int threadId = 0; threadId < threadAmount; threadId++) {
+                        long startIndex = threadId * blockSize;
+                        long endIndex = (threadId + 1) * blockSize - 1;
+                        if (threadId == (threadAmount - 1)) {
+                            endIndex = contentLength - 1;
+                        }
+                        SplitDownload download = new SplitDownload(url, startIndex, endIndex, dest, this);
+                        // Start downloading
+                        executorService.execute(download);
+                        splitDownloads.add(download);
+                    }
+                    long last = 0;
+                    while (true) {
+                        Thread.sleep(1000);
+                        long progress = 0;
+                        // Collect download progress
+                        for (SplitDownload splitDownload : splitDownloads) {
+                            progress += splitDownload.getCurrentIndex() - splitDownload.startIndex;
+                            // blocked then restart from current index
+                            if (!splitDownload.isComplete() &&
+                                    System.currentTimeMillis() - splitDownload.getLastUpdateTime() > maxBlockingTime) {
+                                splitDownload.setStartIndex(splitDownload.getCurrentIndex());
+                                if (splitDownload.getRetry() <= maxRetry)
+                                    executorService.execute(splitDownload);
+                                else throw new RetryFailedException(this);
+                            }
+                        }
+                        // Fire a progress event
+                        if (onProgress != null)
+                            onProgress.handle(new ProgressEvent(progress - last, this,
+                                    ((double) progress) / ((double) contentLength)));
+                        last = progress;
+                        // check complete
+                        if (last >= contentLength) {
+                            break;
+                        }
+                    }
+                    // close the thread pool, release resources
+                    executorService.shutdown();
+                    // change the running flag to false
+                    running = false;
+                }
+                // check hash
+                if (md5 != null && !md5.equalsIgnoreCase(HashUtil.md5(dest)))
+                    throw new HashNotMatchException();
+                if (sha1 != null && !sha1.equalsIgnoreCase(HashUtil.sha1(dest)))
+                    throw new HashNotMatchException();
+                if (sha256 != null && !sha256.equalsIgnoreCase(HashUtil.sha256(dest)))
+                    throw new HashNotMatchException();
+                if (onComplete != null) onComplete.handle(new CompleteEvent(this, true));
+            } catch (Exception e) {
+                onError.handle(new ErrorEvent(e, this));
+                executorService.shutdown();
+                if (onComplete != null) onComplete.handle(new CompleteEvent(this, false));
+            } finally {
+                lock.unlock();
+            }
+        }, "EagletTaskMonitor");
+        monitor.start();
+        return this;
+    }
+
+    public EagletTask waitUntil() {
+        while (lock.tryLock()) lock.unlock();
+        lock.lock();
+        lock.unlock();
+        return this;
+    }
+
+    public EagletTask waitFor(long timeout, TimeUnit unit) {
+        while (lock.tryLock()) lock.unlock();
+        try {
+            lock.tryLock(timeout, unit);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+        return this;
+    }
+
+    public EagletTask maxRetry(int maxRetry) {
+        this.maxRetry = maxRetry;
+        return this;
+    }
+
+    /**
+     * Set the sha256 hash of the download file. Case is not sensitive.
+     * <p>
+     * If the hash check failed, an error event will be fired.
+     *
+     * @param sha256 file sha1
+     * @return task instance
+     */
+    public EagletTask sha256(String sha256) {
+        this.sha256 = sha256;
+        return this;
+    }
+
+    /**
+     * Set the sha1 hash of the download file. Case is not sensitive.
+     * <p>
+     * If the hash check failed, an error event will be fired.
+     *
+     * @param sha1 file sha1
+     * @return task instance
+     */
+    public EagletTask sha1(String sha1) {
+        this.sha1 = sha1;
+        return this;
+    }
+
+    /**
+     * Set the md5 hash of the download file. Case is not sensitive.
+     * <p>
+     * If the hash check failed, an error event will be fired.
+     *
+     * @param md5 file md5
+     * @return task instance
+     */
+    public EagletTask md5(String md5) {
+        this.md5 = md5;
+        return this;
+    }
+
+    /**
+     * Set the max blocked time per download thread.
+     * <p>
+     * If the thread blocks exceeded the provided time, this thread will re-start the task.
+     *
+     * @param maxBlockingTime time
+     * @return task instance
+     */
+    private EagletTask maxBlocking(long maxBlockingTime) {
+        this.maxBlockingTime = maxBlockingTime;
+        return this;
+    }
+
+    /**
+     * Set the progress handler
+     * <p>
+     * This handler will be called every 1000 milli seconds.
+     * <p>
+     * 设置处理进度的时间监听器。该监听器的 handle 方法每秒调用一次。
+     *
+     * @param onProgress handler
+     * @return task instance
+     */
+    public EagletTask setOnProgress(EagletHandler<ProgressEvent> onProgress) {
+        this.onProgress = onProgress;
+        return this;
+    }
+
+    /**
+     * Set the download file
+     *
+     * @param file the file's absolute path
+     * @return task instance
+     */
+    public EagletTask file(String file) {
+        this.dest = new File(file);
+        return this;
+    }
+
+    /**
+     * Set the download file
+     *
+     * @param file the file
+     * @return task instance
+     */
+    public EagletTask file(File file) {
+        this.dest = file;
+        return this;
+    }
+
+    /**
+     * Set the connected handler
+     * <p>
+     * This will be called when the connection is established
+     * <p>
+     * Async call
+     *
+     * @param onConnected onConnected event handler
+     * @return task instance
+     */
+    public EagletTask setOnConnected(EagletHandler<ConnectedEvent> onConnected) {
+        this.onConnected = onConnected;
+        return this;
+    }
+
+    /**
+     * Set the read timeout, default is 7000
+     *
+     * @param timeout timeout
+     * @return task instance
+     */
+    public EagletTask readTimeout(int timeout) {
+        this.readTimeout = timeout;
+        return this;
+    }
+
+    /**
+     * Set the connection timeout, default is 7000
+     *
+     * @param timeout timeout
+     * @return task instance
+     */
+    public EagletTask connectionTimeout(int timeout) {
+        this.connectionTimeout = timeout;
+        return this;
+    }
+
+    /**
+     * Set the request method, default is <code>GET</code>
+     *
+     * @param requestMethod the request method
+     * @return task instance
+     */
+    public EagletTask requestMethod(String requestMethod) {
+        this.requestMethod = requestMethod;
+        return this;
+    }
+
+    /**
+     * Set the complete event handler
+     * <p>
+     * This handler will be called when everything is complete, and the downloaded file is available
+     * <p>
+     * Async call
+     *
+     * @param onComplete the handler
+     * @return task instance
+     */
+    public EagletTask setOnComplete(EagletHandler<CompleteEvent> onComplete) {
+        this.onComplete = onComplete;
+        return this;
+    }
+
+    /**
+     * Set the start handler
+     * <p>
+     * This handler will be called when the <code>start</code> method is called
+     * <p>
+     * Async call
+     *
+     * @param onStart the handler
+     * @return task instance
+     */
+    public EagletTask setOnStart(EagletHandler<StartEvent> onStart) {
+        this.onStart = onStart;
+        return this;
+    }
+
+    /**
+     * Set the network proxy
+     *
+     * @param proxy the proxy
+     * @return task instance
+     */
+    public EagletTask proxy(Proxy proxy) {
+        this.proxy = proxy;
+        return this;
+    }
+
+    /**
+     * Set the error handler, default is to print the stack trace
+     * <p>
+     * This handler will be called when an exception is thrown
+     * <p>
+     * Async call
+     *
+     * @param onError the handler
+     * @return task instance
+     */
+    public EagletTask setOnError(EagletHandler<ErrorEvent> onError) {
+        this.onError = onError;
+        return this;
+    }
+
+
+    /**
+     * Set how much thread should be used to download, default is 1
+     *
+     * @param i thread amount
+     * @return task instance
+     */
+    public EagletTask setThreads(int i) {
+        if (i < 1) throw new RuntimeException("Thread amount cannot be zero or negative!");
+        threadAmount = i;
+        return this;
+    }
+
+    /**
+     * Set the download source
+     *
+     * @param url the url
+     * @return task instance
+     */
+    public EagletTask url(URL url) {
+        this.url = url;
+        return this;
+    }
+
+    /**
+     * Set the download source
+     *
+     * @param url the url
+     * @return task instance
+     */
+    public EagletTask url(String url) {
+        try {
+            this.url = new URL(url);
+        } catch (MalformedURLException e) {
+            onError.handle(new ErrorEvent(e, this));
+        }
+        return this;
+    }
+
+    /**
+     * Clear the http header field
+     *
+     * @return task instance
+     */
+    public EagletTask clearHeaders() {
+        httpHeader.clear();
+        return this;
+    }
+
+    /**
+     * Set the header field of the http request
+     *
+     * @param key   header key
+     * @param value header value
+     * @return builder instance
+     */
+    public EagletTask header(String key, String value) {
+        httpHeader.put(key, value);
+        return this;
+    }
+
+}
diff --git a/src/main/java/com/ilummc/eagletdl/ErrorEvent.java b/src/main/java/com/ilummc/eagletdl/ErrorEvent.java
new file mode 100644
index 0000000..801ac9d
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/ErrorEvent.java
@@ -0,0 +1,20 @@
+package com.ilummc.eagletdl;
+
+public class ErrorEvent {
+
+    private Throwable e;
+    private EagletTask task;
+
+    public ErrorEvent(Throwable e, EagletTask task) {
+        this.e = e;
+        this.task = task;
+    }
+
+    public EagletTask getTask() {
+        return task;
+    }
+
+    public Throwable getException() {
+        return e;
+    }
+}
diff --git a/src/main/java/com/ilummc/eagletdl/HashNotMatchException.java b/src/main/java/com/ilummc/eagletdl/HashNotMatchException.java
new file mode 100644
index 0000000..bdb3bcd
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/HashNotMatchException.java
@@ -0,0 +1,4 @@
+package com.ilummc.eagletdl;
+
+public class HashNotMatchException extends RuntimeException {
+}
diff --git a/src/main/java/com/ilummc/eagletdl/HashUtil.java b/src/main/java/com/ilummc/eagletdl/HashUtil.java
new file mode 100644
index 0000000..10bf013
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/HashUtil.java
@@ -0,0 +1,63 @@
+package com.ilummc.eagletdl;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.math.BigInteger;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+public class HashUtil {
+
+    public static String sha256(File file) {
+        try {
+            FileInputStream fis = new FileInputStream(file);
+            MessageDigest md = MessageDigest.getInstance("SHA256");
+            byte[] buffer = new byte[1024];
+            int length = -1;
+            while ((length = fis.read(buffer, 0, 1024)) != -1) {
+                md.update(buffer, 0, length);
+            }
+            BigInteger bigInt = new BigInteger(1, md.digest());
+            return bigInt.toString(16);
+        } catch (NoSuchAlgorithmException | IOException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    public static String sha1(File file) {
+        try {
+            FileInputStream fis = new FileInputStream(file);
+            MessageDigest md = MessageDigest.getInstance("SHA1");
+            byte[] buffer = new byte[1024];
+            int length = -1;
+            while ((length = fis.read(buffer, 0, 1024)) != -1) {
+                md.update(buffer, 0, length);
+            }
+            BigInteger bigInt = new BigInteger(1, md.digest());
+            return bigInt.toString(16);
+        } catch (NoSuchAlgorithmException | IOException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    public static String md5(File file) {
+        try {
+            FileInputStream fis = new FileInputStream(file);
+            MessageDigest md = MessageDigest.getInstance("MD5");
+            byte[] buffer = new byte[1024];
+            int length = -1;
+            while ((length = fis.read(buffer, 0, 1024)) != -1) {
+                md.update(buffer, 0, length);
+            }
+            BigInteger bigInt = new BigInteger(1, md.digest());
+            return bigInt.toString(16);
+        } catch (NoSuchAlgorithmException | IOException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+}
diff --git a/src/main/java/com/ilummc/eagletdl/ProgressEvent.java b/src/main/java/com/ilummc/eagletdl/ProgressEvent.java
new file mode 100644
index 0000000..f6cf1b7
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/ProgressEvent.java
@@ -0,0 +1,53 @@
+package com.ilummc.eagletdl;
+
+import java.text.DecimalFormat;
+
+public class ProgressEvent {
+
+    private long speed;
+    private EagletTask task;
+    private double percentage;
+
+    ProgressEvent(long speed, EagletTask task, double percentage) {
+        this.speed = speed;
+        this.task = task;
+        this.percentage = percentage;
+    }
+
+    public EagletTask getTask() {
+        return task;
+    }
+
+    public long getSpeed() {
+        return speed;
+    }
+
+    public double getPercentage() {
+        return percentage;
+    }
+
+    public String getPercentageFormatted() {
+        return formatDouble(percentage * 100D) + " %";
+    }
+
+    /**
+     * Get the speed with format like <code>X.00 MiB</code>, <code>Y.50 GiB</code>, etc.
+     *
+     * @return formatted speed string
+     */
+    public String getSpeedFormatted() {
+        return format(getSpeed());
+    }
+
+    private static String formatDouble(double d) {
+        return new DecimalFormat("0.00").format(d);
+    }
+
+    public static String format(long l) {
+        if (l < 1024) return l + " B";
+        if (l < 1024 * 1024) return formatDouble((double) l / 1024D) + " KiB";
+        if (l < 1024 * 1024 * 1024) return formatDouble((double) l / (1024D * 1024D)) + " MiB";
+        if (l < 1024 * 1024 * 1024 * 1024L) return formatDouble((double) l / (1024D * 1024D * 1024)) + " GiB";
+        return "";
+    }
+}
diff --git a/src/main/java/com/ilummc/eagletdl/RetryFailedException.java b/src/main/java/com/ilummc/eagletdl/RetryFailedException.java
new file mode 100644
index 0000000..e8a022d
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/RetryFailedException.java
@@ -0,0 +1,14 @@
+package com.ilummc.eagletdl;
+
+public class RetryFailedException extends RuntimeException {
+
+    private EagletTask task;
+
+    RetryFailedException(EagletTask task) {
+        this.task = task;
+    }
+
+    public EagletTask getTask() {
+        return task;
+    }
+}
diff --git a/src/main/java/com/ilummc/eagletdl/SingleThreadDownload.java b/src/main/java/com/ilummc/eagletdl/SingleThreadDownload.java
new file mode 100644
index 0000000..137762d
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/SingleThreadDownload.java
@@ -0,0 +1,50 @@
+package com.ilummc.eagletdl;
+
+import java.io.*;
+import java.net.HttpURLConnection;
+
+class SingleThreadDownload implements Runnable {
+
+    private HttpURLConnection connection;
+    private File target;
+    private EagletTask task;
+
+    private transient long currentProgress = 0, lastUpdateTime = System.currentTimeMillis();
+
+    private transient boolean complete = false;
+
+    SingleThreadDownload(HttpURLConnection connection, File target, EagletTask task) {
+        this.connection = connection;
+        this.target = target;
+        this.task = task;
+    }
+
+    long getLastUpdateTime() {
+        return lastUpdateTime;
+    }
+
+    long getCurrentProgress() {
+        return currentProgress;
+    }
+
+    public boolean isComplete() {
+        return complete;
+    }
+
+    @Override
+    public void run() {
+        byte[] buf = new byte[1024];
+        int len = 0;
+        try (BufferedInputStream stream = new BufferedInputStream(connection.getInputStream());
+             BufferedOutputStream outputStream = new BufferedOutputStream(new FileOutputStream(target))) {
+            while ((len = stream.read(buf)) > 0) {
+                outputStream.write(buf, 0, len);
+                currentProgress += len;
+                lastUpdateTime = System.currentTimeMillis();
+            }
+        } catch (IOException e) {
+            task.onError.handle(new ErrorEvent(e, task));
+        }
+        complete = true;
+    }
+}
diff --git a/src/main/java/com/ilummc/eagletdl/SplitDownload.java b/src/main/java/com/ilummc/eagletdl/SplitDownload.java
new file mode 100644
index 0000000..6727537
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/SplitDownload.java
@@ -0,0 +1,89 @@
+package com.ilummc.eagletdl;
+
+import java.io.BufferedInputStream;
+import java.io.File;
+import java.io.RandomAccessFile;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+class SplitDownload implements Runnable {
+
+    private URL url;
+    long startIndex, endIndex;
+    private File target;
+    private EagletTask task;
+
+    private transient long currentIndex, lastUpdateTime = System.currentTimeMillis(), tmpStart;
+    private transient int retry = 0;
+    private transient boolean complete;
+
+    SplitDownload(URL url, long startIndex, long endIndex, File dest, EagletTask task) {
+        this.url = url;
+        tmpStart = this.startIndex = this.currentIndex = startIndex;
+        this.endIndex = endIndex;
+        target = dest;
+        this.task = task;
+    }
+
+    void setStartIndex(long index) {
+        this.tmpStart = index;
+    }
+
+    long getLastUpdateTime() {
+        return lastUpdateTime;
+    }
+
+    long getCurrentIndex() {
+        return currentIndex;
+    }
+
+    int getRetry() {
+        return retry;
+    }
+
+    boolean isComplete() {
+        return complete || currentIndex == endIndex + 1;
+    }
+
+    @Override
+    public void run() {
+        try {
+            complete = false;
+            currentIndex = tmpStart;
+            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
+            // set the connection properties
+            task.httpHeader.forEach(connection::addRequestProperty);
+            connection.setRequestMethod(task.requestMethod);
+            connection.setConnectTimeout(task.connectionTimeout);
+            connection.setReadTimeout(task.readTimeout);
+            // set the download range
+            connection.setRequestProperty("Range", "bytes=" + tmpStart + "-" + endIndex);
+            connection.connect();
+            // if response code not equals 206, it means that the server do not support multi thread downloading
+            if (connection.getResponseCode() == 206) {
+                RandomAccessFile file = new RandomAccessFile(target, "rwd");
+                file.seek(tmpStart);
+                byte[] buf = new byte[1024];
+                int len;
+                try (BufferedInputStream stream = new BufferedInputStream(connection.getInputStream())) {
+                    while ((len = stream.read(buf)) > 0) {
+                        file.write(buf, 0, len);
+                        lastUpdateTime = System.currentTimeMillis();
+                        currentIndex += len;
+                        // some mysterious error occurred while downloading
+                        if (currentIndex >= endIndex + 2) {
+                            currentIndex = tmpStart;
+                            lastUpdateTime = 0;
+                            retry++;
+                            return;
+                        }
+                    }
+                    complete = true;
+                }
+            } else throw new DoNotSupportMultipleThreadException();
+        } catch (Exception e) {
+            task.onError.handle(new ErrorEvent(e, task));
+            retry++;
+        }
+    }
+}
diff --git a/src/main/java/com/ilummc/eagletdl/StartEvent.java b/src/main/java/com/ilummc/eagletdl/StartEvent.java
new file mode 100644
index 0000000..b0c7f61
--- /dev/null
+++ b/src/main/java/com/ilummc/eagletdl/StartEvent.java
@@ -0,0 +1,14 @@
+package com.ilummc.eagletdl;
+
+public class StartEvent {
+
+    private EagletTask task;
+
+    StartEvent(EagletTask task) {
+        this.task = task;
+    }
+
+    public EagletTask getTask() {
+        return task;
+    }
+}