diff --git a/group24/121111914/src/com/github/ipk2015/coding2017/basic/LinkedList.java b/group24/121111914/src/com/github/ipk2015/coding2017/basic/LinkedList.java
index d10c40a563..7afb0e5500 100644
--- a/group24/121111914/src/com/github/ipk2015/coding2017/basic/LinkedList.java
+++ b/group24/121111914/src/com/github/ipk2015/coding2017/basic/LinkedList.java
@@ -171,7 +171,18 @@ private static  class Node{
 	 * 例如链表为 3->7->10 , 逆置后变为  10->7->3
 	 */
 	public  void reverse(){		
-		
+		if(null==head){
+			return;
+		}
+		Node tempNode=new Node();
+		Node currentNode=head.next;
+		head.next=null;
+		while(null!=currentNode){
+			tempNode=currentNode.next;
+			currentNode.next=head;
+			head=currentNode;
+			currentNode=tempNode;
+		}
 	}
 	
 	/**
@@ -181,7 +192,17 @@ public  void reverse(){
 
 	 */
 	public  void removeFirstHalf(){
-		
+		if(null==head){
+			return;
+		}
+		Node tempNode;
+		int size=size();
+		size=size/2;
+		for(int i=0;i<size;i++){
+			tempNode=head;
+			head=head.next;
+			tempNode.next=null;
+		}
 	}
 	
 	/**
@@ -189,8 +210,31 @@ public  void removeFirstHalf(){
 	 * @param i
 	 * @param length
 	 */
-	public  void remove(int i, int length){
-		
+	public  void remove(int index, int length){
+		ListUtils.checkIndexInRange(index+length, size());
+		if(null==head){
+			return;
+		}
+		Node tempNode;
+		if(index==0){
+			for(int i=0;i<length;i++){
+				tempNode=head;
+				head=head.next;
+				tempNode.next=null;
+			}
+			return;
+		}
+		Node startNode=head;
+		for(int i=0;i<index-1;i++){
+			startNode=startNode.next;
+		}
+		Node endNode=startNode.next;
+		for(int i=0;i<length;i++){
+			tempNode=endNode;
+			endNode=endNode.next;
+			tempNode.next=null;
+		}
+		startNode.next=endNode;
 	}
 	/**
 	 * 假定当前链表和list均包含已升序排列的整数
@@ -200,8 +244,25 @@ public  void remove(int i, int length){
 	 * 返回的结果应该是[101,301,401,601]  
 	 * @param list
 	 */
-	public static int[] getElements(LinkedList list){
-		return null;
+	public  int[] getElements(LinkedList list){
+		int[] array=new int[list.size()];
+		Iterator iterator = list.iterator();
+		int temp=0,next=0,size=0,oriSize=size();
+		Node tempNode=head;
+		while(iterator.hasNext()){
+			next = (Integer) iterator.next();
+			if(next>=oriSize){
+				break;
+			}
+			temp=next-temp;
+			for(int i=0;i<temp;i++){
+				tempNode=tempNode.next;
+			}
+			array[size]=(Integer)tempNode.data;
+			temp=next;
+			size++;
+		}
+		return array;
 	}
 	
 	/**
@@ -212,7 +273,45 @@ public static int[] getElements(LinkedList list){
 	 */
 	
 	public  void subtract(LinkedList list){
-		
+		if(null==head){
+			return;
+		}
+		Iterator iterator = list.iterator();
+		Node tempNode=head;
+		Node preNode=head;
+		Node currentNode=head;
+		int next,tempData=(Integer)head.data;
+		boolean isEnd=false;
+		while(iterator.hasNext()){
+			next = (Integer) iterator.next();
+			while(tempData<next){
+				preNode=currentNode;
+				currentNode=currentNode.next;
+				if(null==currentNode){
+					isEnd=true;
+					break;
+				}
+				tempData=(Integer)currentNode.data;
+			} 
+			if(isEnd){
+				break;
+			}
+			if(tempData>next){
+				continue;
+			}
+			if(currentNode==head){
+				head=head.next;
+			}else{   
+				preNode.next=currentNode.next;
+			}
+			tempNode=currentNode;
+			currentNode=currentNode.next;
+			tempNode.next=null;
+			if(null==currentNode){
+				break;
+			}
+			tempData=(Integer)currentNode.data;
+		}
 	}
 	
 	/**
@@ -220,17 +319,91 @@ public  void subtract(LinkedList list){
 	 * 删除表中所有值相同的多余元素（使得操作后的线性表中所有元素的值均不相同）
 	 */
 	public  void removeDuplicateValues(){
-		
+		Node currentNode=head;
+		Node tempNode=head;
+		int tempData;
+		while(null!=currentNode && null!=currentNode.next){
+			tempData=(Integer)currentNode.data;
+			if(tempData==(Integer)currentNode.next.data){
+				if(null!=currentNode.next.next){
+					tempNode=currentNode.next;
+					currentNode.next=currentNode.next.next;
+					tempNode.next=null;
+				}else{
+					currentNode.next=null;
+				}
+			}else{
+				currentNode=currentNode.next;
+			}
+		}
 	}
 	
 	/**
 	 * 已知链表中的元素以值递增有序排列，并以单链表作存储结构。
-	 * 试写一高效的算法，删除表中所有值大于min且小于max的元素（若表中存在这样的元素）
+	 * 试写一高效的算法，删除表中所有值大于等于min且小于等于max的元素（若表中存在这样的元素）
 	 * @param min
 	 * @param max
 	 */
 	public  void removeRange(int min, int max){
-		
+		if(null==head){
+			return;
+		}
+		int size=size();
+		int headData=(Integer)head.data;
+		int endData=(Integer)get(size-1);
+		if(headData>=min && endData<=max){
+			head=null;
+			return;
+		}
+		if(headData>max || endData<min){
+			return;
+		}
+		int startIndex=searchIndexInRange(min,0,size-1);
+		if((Integer)get(startIndex)<min){
+			startIndex++;
+		}
+		int endIndex=searchIndexInRange(max,startIndex,size-1);
+		if(startIndex==0){
+			for(int i=0;i<endIndex+1;i++){
+				head=head.next;
+			}
+		}else{
+			Node beforeNode=head;
+			for(int i=0;i<startIndex-1;i++){
+				beforeNode=beforeNode.next;
+			}
+			Node curNode=beforeNode;
+			for(int i=startIndex-2;i<endIndex;i++){
+				curNode=curNode.next; 
+			}
+			beforeNode.next=curNode;
+		}
+	}
+	/*
+	 * 返回的index所在位的值小于等于arm
+	 * */
+	private int searchIndexInRange(int arm,int beginIndex,int endIndex){
+		int tempData=(Integer)get(beginIndex);
+		if(tempData>=arm){
+			return beginIndex;
+		}
+		tempData=(Integer)get(endIndex);
+		if(tempData<=arm){
+			return endIndex;
+		}
+		int middleIndex=0;
+		while(beginIndex<endIndex-1){
+			middleIndex=(beginIndex+endIndex)/2;
+			tempData=(Integer)get(middleIndex);
+			if(tempData<arm){
+				beginIndex=middleIndex;
+			}else if(tempData>arm){
+				endIndex=middleIndex;
+			}else{
+				break;
+			}
+		}
+		return middleIndex;
 	}
 	
 	/**
@@ -239,6 +412,31 @@ public  void removeRange(int min, int max){
 	 * @param list
 	 */
 	public  LinkedList rsection( LinkedList list){
-		return null;
+		LinkedList armList=new LinkedList();
+		Node tempNode=head;
+		if(null==list || list.size()==0){
+			while(null!=tempNode){
+				armList.add(tempNode.data);
+				tempNode=tempNode.next;
+			}
+		}else{
+			Iterator iterator = list.iterator();
+			Integer next;
+			Integer data;
+			while(iterator.hasNext()){
+				next = (Integer)iterator.next();
+				while(null!=tempNode){
+					data = (Integer)tempNode.data;
+					if(data<next){
+						armList.add(data);
+						tempNode=tempNode.next;
+					}else{
+						break;
+					}
+				}
+				armList.add(next);
+			}
+		}
+		return armList;
 	}
 }
diff --git a/group24/121111914/src/com/github/ipk2015/coding2017/basic/test/LinkedListTest.java b/group24/121111914/src/com/github/ipk2015/coding2017/basic/test/LinkedListTest.java
index 57fed394d6..0bbda2cab4 100644
--- a/group24/121111914/src/com/github/ipk2015/coding2017/basic/test/LinkedListTest.java
+++ b/group24/121111914/src/com/github/ipk2015/coding2017/basic/test/LinkedListTest.java
@@ -2,9 +2,12 @@
 
 import static org.junit.Assert.*;
 
+import java.util.Arrays;
+
 import org.junit.Before;
 import org.junit.Test;
 
+import com.github.ipk2015.coding2017.basic.Iterator;
 import com.github.ipk2015.coding2017.basic.LinkedList;
 
 public class LinkedListTest {
@@ -13,7 +16,16 @@ public class LinkedListTest {
 	public void setUp() throws Exception {
 		list=new LinkedList(); 
 	}
-
+	private static String toString(LinkedList list){
+		Iterator iterator = list.iterator();
+		StringBuilder builder=new StringBuilder();
+		int next;
+		while(iterator.hasNext()){
+			next = (Integer)iterator.next();
+			builder.append(next+",");
+		}
+		return builder.toString();
+	}
 	@Test
 	public void testAddObject() {
 		list.add("hehe1");
@@ -88,5 +100,142 @@ public void testRemoveLast() {
 		list.removeLast();
 		assertEquals("hehe2", list.get(list.size()-1));
 	}
+	@Test
+	public void testReverse() {
+		list.add(1);
+		list.add(2);
+		list.add(3);
+		list.add(4);
+		list.reverse();
+		assertEquals("4,3,2,1,", toString(list));
+	}
+
+	@Test
+	public void testRemoveFirstHalf() {
+		list.add(1);
+		list.add(2);
+		list.add(3);
+		list.add(4);
+		list.add(5);
+		list.removeFirstHalf();
+		assertEquals("3,4,5,", toString(list));
+	}
+
+	@Test
+	public void testRemoveIntInt() {
+		list.add(1);
+		list.add(3);
+		list.add(5);
+		list.add(7);
+		list.add(9);
+		list.add(10);
+		list.add(11);
+		list.remove(3, 2);
+		assertEquals("1,3,5,10,11,", toString(list));
+		list.remove(0, 3);
+		assertEquals("10,11,", toString(list));
+	}
+
+	@Test
+	public void testGetElements() {
+		list.add(11);
+		list.add(101);
+		list.add(201);
+		list.add(301);
+		list.add(401);
+		list.add(501);
+		list.add(601);
+		list.add(701);
+		LinkedList mList=new LinkedList();
+		mList.add(1);
+		mList.add(3);
+		mList.add(4);
+		mList.add(6);
+		int[] elements = list.getElements(mList);
+		assertEquals("[101,301,401,601]", Arrays.toString(elements).replaceAll(" ", ""));
+	}
+
+	@Test
+	public void testSubtract() {
+		list.add(11);
+		list.add(101);
+		list.add(201);
+		list.add(301);
+		list.add(401);
+		list.add(501);
+		list.add(601);
+		list.add(701);
+		LinkedList mList=new LinkedList();
+		mList.add(101);
+		mList.add(301);
+		mList.add(501);
+		mList.add(601);
+		list.subtract(mList);
+		assertEquals("11,201,401,701,", toString(list));
+	}
+
+	@Test
+	public void testRemoveDuplicateValues() {
+		list.add(11);
+		list.add(11);
+		list.add(101);
+		list.add(101);
+		list.add(101);
+		list.add(201);
+		list.add(301);
+		list.add(301);
+		list.add(401);
+		list.add(401);
+		list.add(501);
+		list.removeDuplicateValues();
+		assertEquals("11,101,201,301,401,501,", toString(list));
+	}
+
+	@Test
+	public  void testRemoveRange() {
+		list.add(11);
+		list.add(101);
+		list.add(201);
+		list.add(301);
+		list.add(401);
+		list.add(501);
+		list.add(601);
+		list.add(701);
+		list.add(801);
+		list.add(901);
+		list.add(1001);
+		
+		list.removeRange(801, 1101);
+		assertEquals("11,101,201,301,401,501,601,701,", toString(list));
+		list.removeRange(100, 400);
+		assertEquals("11,401,501,601,701,", toString(list));
+		list.removeRange(1, 500);
+		assertEquals("501,601,701,", toString(list));
+		list.removeRange(700, 900);
+		assertEquals("501,601,", toString(list));
+		list.removeRange(1,200);
+		assertEquals("501,601,", toString(list));
+		list.removeRange(700, 900);
+		assertEquals("501,601,", toString(list));
+		list.removeRange(1, 700);
+		assertEquals("", toString(list));
+	}
+
+	@Test
+	public void testRsection() {
+		list.add(11);
+		list.add(21);
+		list.add(31);
+		LinkedList mList=new LinkedList();
+		mList.add(1);
+		mList.add(2);
+		mList.add(11);
+		mList.add(25);
+		mList.add(35);
+		mList=list.rsection(mList);
+		assertEquals("1,2,11,11,21,25,31,35,", toString(mList));
+	}
+
+	
 
 }
diff --git a/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/DownloadThread.java b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/DownloadThread.java
new file mode 100644
index 0000000000..3e2ca7ca62
--- /dev/null
+++ b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/DownloadThread.java
@@ -0,0 +1,37 @@
+package com.github.ipk2015.coding2017.coderising.download;
+
+import java.io.IOException;
+
+import com.github.ipk2015.coding2017.coderising.download.api.Connection;
+import com.github.ipk2015.coding2017.coderising.download.api.DownloadListener;
+
+public class DownloadThread extends Thread{
+
+	Connection conn;
+	int startPos;
+	int endPos;
+	int threadId;
+	DownloadListener listener;
+	public DownloadThread( Connection conn, int startPos, int endPos){
+		super();
+		this.conn = conn;		
+		this.startPos = startPos;
+		this.endPos = endPos;
+	}
+	public DownloadThread( Connection conn, int startPos, int endPos,int threadId,DownloadListener listener){
+		super();
+		this.conn = conn;		
+		this.startPos = startPos;
+		this.endPos = endPos;
+		this.threadId=threadId;
+		this.listener=listener;
+	}
+	public void run(){	
+		try {
+			conn.read(startPos,endPos,threadId,listener);
+		} catch (IOException e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+	}
+}
diff --git a/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/FileDownloader.java b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/FileDownloader.java
new file mode 100644
index 0000000000..5484ad0fad
--- /dev/null
+++ b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/FileDownloader.java
@@ -0,0 +1,96 @@
+ package com.github.ipk2015.coding2017.coderising.download;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.InputStreamReader;
+import java.io.RandomAccessFile;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+import com.github.ipk2015.coding2017.coderising.download.api.Connection;
+import com.github.ipk2015.coding2017.coderising.download.api.ConnectionException;
+import com.github.ipk2015.coding2017.coderising.download.api.ConnectionManager;
+import com.github.ipk2015.coding2017.coderising.download.api.DownloadListener;
+import com.github.ipk2015.coding2017.coderising.download.impl.ConnectionImpl;
+import com.github.ipk2015.coding2017.coderising.download.impl.ConnectionManagerImpl;
+
+public class FileDownloader {
+	
+	String url;
+	int threadCount=1;
+	DownloadListener listener;
+	
+	ConnectionManager cm;
+	
+
+	public FileDownloader(String _url) {
+		this.url = _url;
+	}
+	public FileDownloader(String _url,int _threadCount){
+		this.url = _url;
+		this.threadCount=_threadCount;
+		ConnectionImpl.threadCount=_threadCount;
+	}
+	public void execute() throws Exception{
+		// 在这里实现你的代码， 注意： 需要用多线程实现下载
+		// 这个类依赖于其他几个接口, 你需要写这几个接口的实现代码
+		// (1) ConnectionManager , 可以打开一个连接，通过Connection可以读取其中的一段（用startPos, endPos来指定）
+		// (2) DownloadListener, 由于是多线程下载， 调用这个类的客户端不知道什么时候结束，所以你需要实现当所有
+		//     线程都执行完以后， 调用listener的notifiedFinished方法， 这样客户端就能收到通知。
+		// 具体的实现思路：
+		// 1. 需要调用ConnectionManager的open方法打开连接， 然后通过Connection.getContentLength方法获得文件的长度
+		// 2. 至少启动3个线程下载，  注意每个线程需要先调用ConnectionManager的open方法
+		// 然后调用read方法， read方法中有读取文件的开始位置和结束位置的参数， 返回值是byte[]数组
+		// 3. 把byte数组写入到文件中
+		// 4. 所有的线程都下载完成以后， 需要调用listener的notifiedFinished方法
+		
+		// 下面的代码是示例代码， 也就是说只有一个线程， 你需要改造成多线程的。
+		Connection conn = this.cm.open(url);
+		int length=conn.getContentLength();
+		if(length<=0){
+			System.out.println("获取下载文件长度失败");
+			return;
+		}
+		int lastIndexOf = url.lastIndexOf("/");
+		RandomAccessFile raf = new RandomAccessFile(url.substring(lastIndexOf+1), "rwd");
+		raf.setLength(length);
+		for(int threadId=0; threadId<threadCount; threadId++){
+			int blockSize = length/threadCount;
+			int startIndex = threadId*blockSize;
+			
+			// 下次下载时,读取临时文件,得到上次下载到的位置,接着这个位置继续下载
+			File file = new File(threadId+".txt");
+			if(file.exists() && file.length() > 0){
+				FileInputStream fileInputStream =new FileInputStream(file);
+				InputStreamReader inputStreamReader =new InputStreamReader(fileInputStream);
+				BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
+				String content = bufferedReader.readLine();
+				int currentPosition = Integer.parseInt(content);
+				startIndex = currentPosition;
+			}
+			
+			int endIndex = (threadId+1)*blockSize-1;
+			if(threadId == threadCount-1){
+				endIndex = length-1;
+			}
+			Connection connection = cm.open(url);
+			new DownloadThread(connection,startIndex,endIndex,threadId,listener).start();
+		}
+	}
+	
+	public void setListener(DownloadListener listener) {
+		this.listener = listener;
+	}
+
+	
+	
+	public void setConnectionManager(ConnectionManager ucm){
+		this.cm = ucm;
+	}
+	
+	public DownloadListener getListener(){
+		return this.listener;
+	}
+	
+}
diff --git a/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/FileDownloaderTest.java b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/FileDownloaderTest.java
new file mode 100644
index 0000000000..10e9dbfa46
--- /dev/null
+++ b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/FileDownloaderTest.java
@@ -0,0 +1,66 @@
+package com.github.ipk2015.coding2017.coderising.download;
+
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.github.ipk2015.coding2017.coderising.download.api.ConnectionManager;
+import com.github.ipk2015.coding2017.coderising.download.api.DownloadListener;
+import com.github.ipk2015.coding2017.coderising.download.impl.ConnectionManagerImpl;
+
+
+
+public class FileDownloaderTest {
+	boolean downloadFinished = false;
+	@Before
+	public void setUp() throws Exception {
+	}
+
+	@After
+	public void tearDown() throws Exception {
+	}
+
+	@Test
+	public void testDownload() {
+		
+		String url = "http://dldir1.qq.com/qqfile/qq/QQ8.9.1/20437/QQ8.9.1.exe";
+		int threadCount=3;
+		FileDownloader downloader = new FileDownloader(url,threadCount);
+
+	
+		ConnectionManager cm = new ConnectionManagerImpl();
+		downloader.setConnectionManager(cm);
+		
+		downloader.setListener(new DownloadListener() {
+			@Override
+			public void notifyFinished() {
+					downloadFinished = true;
+					System.out.println("下载完成啦");
+			}
+
+		});
+
+		
+		try {
+			downloader.execute();
+		} catch (Exception e1) {
+			// TODO Auto-generated catch block
+			e1.printStackTrace();
+		}
+		
+		// 等待多线程下载程序执行完毕
+//		while (!downloadFinished) {
+//			try {
+//				System.out.println("还没有下载完成，休眠五秒");
+//				//休眠5秒
+//				Thread.sleep(5000);
+//			} catch (InterruptedException e) {				
+//				e.printStackTrace();
+//			}
+//		}
+//		System.out.println("下载完成！");
+
+	}
+
+}
diff --git a/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/Connection.java b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/Connection.java
new file mode 100644
index 0000000000..c7a61ac781
--- /dev/null
+++ b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/Connection.java
@@ -0,0 +1,32 @@
+package com.github.ipk2015.coding2017.coderising.download.api;
+
+
+
+import java.io.IOException;
+
+public interface Connection {
+	/**
+	 * 给定开始和结束位置， 读取数据， 返回值是字节数组
+	 * @param startPos 开始位置， 从0开始
+	 * @param endPos 结束位置
+	 * @return
+	 */
+	public byte[] read(int startPos,int endPos) throws IOException;
+	/**
+	 * 给定开始和结束位置， 读取数据,适用于多线程下载
+	 * @param startPos 开始位置， 从0开始
+	 * @param endPos 结束位置
+	 * @return
+	 */
+	public void read(int startPos,int endPos,int threadId,DownloadListener listener) throws IOException;
+	/**
+	 * 得到数据内容的长度
+	 * @return
+	 */
+	public int getContentLength();
+	
+	/**
+	 * 关闭连接
+	 */
+	public void close();
+}
diff --git a/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/ConnectionException.java b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/ConnectionException.java
new file mode 100644
index 0000000000..780ed30029
--- /dev/null
+++ b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/ConnectionException.java
@@ -0,0 +1,5 @@
+package com.github.ipk2015.coding2017.coderising.download.api;
+
+public class ConnectionException extends Exception {
+
+}
diff --git a/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/ConnectionManager.java b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/ConnectionManager.java
new file mode 100644
index 0000000000..cfa76e4ea6
--- /dev/null
+++ b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/ConnectionManager.java
@@ -0,0 +1,10 @@
+package com.github.ipk2015.coding2017.coderising.download.api;
+
+public interface ConnectionManager {
+	/**
+	 * 给定一个url , 打开一个连接
+	 * @param url
+	 * @return
+	 */
+	public Connection open(String url) throws ConnectionException;
+}
diff --git a/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/DownloadListener.java b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/DownloadListener.java
new file mode 100644
index 0000000000..97ceef6416
--- /dev/null
+++ b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/api/DownloadListener.java
@@ -0,0 +1,5 @@
+package com.github.ipk2015.coding2017.coderising.download.api;
+
+public interface DownloadListener {
+	public void notifyFinished();
+}
diff --git a/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/impl/ConnectionImpl.java b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/impl/ConnectionImpl.java
new file mode 100644
index 0000000000..bf60948390
--- /dev/null
+++ b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/impl/ConnectionImpl.java
@@ -0,0 +1,97 @@
+package com.github.ipk2015.coding2017.coderising.download.impl;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.RandomAccessFile;
+import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
+import java.net.ProtocolException;
+import java.net.URL;
+
+import com.github.ipk2015.coding2017.coderising.download.api.Connection;
+import com.github.ipk2015.coding2017.coderising.download.api.DownloadListener;
+
+
+public class ConnectionImpl implements Connection{
+	private String path;
+	public static int threadCount=0;
+	public ConnectionImpl(String path){
+		super();
+		this.path=path; 
+	}
+	
+
+	@Override
+	public int getContentLength()  {
+		URL url;
+		int length=0;
+		try {
+			url = new URL(path);
+			HttpURLConnection conn = (HttpURLConnection) url.openConnection();
+			conn.setRequestMethod("GET");
+			conn.setConnectTimeout(3000);
+			int code = conn.getResponseCode();
+			System.out.println("code:"+code+"");
+			if(code == 200){
+				// 获得服务器端文件的大小
+				length = conn.getContentLength();
+			}
+		} catch (Exception e) {
+			// TODO Auto-generated catch block
+			e.printStackTrace();
+		}
+		return length;
+	}
+
+	@Override
+	public void close() {
+		
+		
+	}
+	@Override
+	public byte[] read(int startPos, int endPos) throws IOException {
+		
+		return null;
+	}
+
+
+	@Override
+	public void read(int startPos, int endPos,int threadId,DownloadListener listener) throws IOException {
+		URL url=new URL(path);
+		HttpURLConnection conn=(HttpURLConnection) url.openConnection();
+		conn.setRequestMethod("GET");
+		conn.setConnectTimeout(3000);
+		conn.setRequestProperty("Range", "bytes="+startPos+"-"+endPos);
+		int code=conn.getResponseCode();
+		if(code==206){
+			InputStream inputStream = conn.getInputStream();
+			int lastIndexOf = path.lastIndexOf("/");
+			RandomAccessFile randomAccessFile = new RandomAccessFile(path.substring(lastIndexOf+1),"rwd");
+			RandomAccessFile tempPositionFile = new RandomAccessFile(threadId+".txt","rwd");
+			randomAccessFile.seek(startPos);
+			int length=-1,total=0;
+			byte[] buffer=new byte[1024*500];
+			while((length=inputStream.read(buffer))!=-1){
+				randomAccessFile.write(buffer,0,length);
+				total=total+length;
+				tempPositionFile.write(((startPos+total)+"").getBytes());
+			}
+			tempPositionFile.close();
+			randomAccessFile.close();
+			inputStream.close();
+			synchronized (ConnectionImpl.class) {
+				//把当前线程的临时文件删除
+				File file = new File(threadId+".txt");
+				if(file.exists()){
+					file.delete();
+				}
+				threadCount--;
+				if(threadCount==0){
+					listener.notifyFinished();
+				}
+			}
+		}
+	}
+
+}
diff --git a/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/impl/ConnectionManagerImpl.java b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/impl/ConnectionManagerImpl.java
new file mode 100644
index 0000000000..50169258f1
--- /dev/null
+++ b/group24/121111914/src/com/github/ipk2015/coding2017/coderising/download/impl/ConnectionManagerImpl.java
@@ -0,0 +1,18 @@
+package com.github.ipk2015.coding2017.coderising.download.impl;
+
+import java.io.RandomAccessFile;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+import com.github.ipk2015.coding2017.coderising.download.api.Connection;
+import com.github.ipk2015.coding2017.coderising.download.api.ConnectionException;
+import com.github.ipk2015.coding2017.coderising.download.api.ConnectionManager;
+
+public class ConnectionManagerImpl implements ConnectionManager {
+
+	@Override
+	public Connection open(String url) throws ConnectionException {
+		Connection conn=new ConnectionImpl(url);
+		return conn;
+	}
+}