DonaldY · DonaldY · Apr 7, 2017 · Apr 5, 2017
diff --git a/group24/330657387/src/main/week01/data_structure/LinkedList.java b/group24/330657387/src/main/week01/data_structure/LinkedList.java
@@ -194,7 +194,7 @@ public void removeFirstHalf() {
 	 */
 	public void remove(int i, int length) {
 		rangeCheck(i);
-		rangeCheck(i + length - 1);
+		rangeCheck(i + length - 1);//或者当length超出长度，直接认为删除i后面的所有部分。
 		if (i == 0) {
 			head = getNode(length);
 			size -= length;
@@ -216,8 +216,13 @@ public int[] getElements(LinkedList list) throws Exception {
 		if (list == null) {
 			throw new Exception("传入链表为空？");
 		}
+
 		int[] res = new int[list.size];
 		for (int i = 0; i < list.size; i++) {
+			//这个list里的值不一定合法的。可以跳过那些不合法的值。
+			if(i > size - 1){
+				continue;
+			}
 			res[i] = Integer.parseInt(get(
 					Integer.parseInt(list.get(i).toString()) - 1).toString());
 		}
@@ -298,6 +303,7 @@ public void removeRange(int min, int max) throws Exception {
 			 lastRemove = iter.position - 1;
 			}
 		}
+		//移动指针的时候，注意不要留下指空的指针。不然相关node会无法被gc
 		if(hasmin && firstRemove == 0){
 			head = getNode(lastRemove);
 			size -= lastRemove-firstRemove+1;
@@ -318,44 +324,28 @@ public void removeRange(int min, int max) throws Exception {
 	 * @param list
 	 */
 	public LinkedList intersection(LinkedList list) {
-		if(0 == list.size){
-			return this;
-		}
-		if(0 == size){
-			return list;
+		if(0 == list.size || 0 == size){
+			return new LinkedList();
 		}
+
 		LinkedList res = new LinkedList();
-		Node a = head, b = list.head;
-		while(null != a && null != b){
-			if(a.equals(b)){
-				res.add(a.data);
-				a = a.next;
-				b = b.next;
-				continue;
+		Node node1 = this.head;
+		Node node2 = list.head;
+		while(node1 != null && node2 != null){
+			if((int)node1.data<(int)node2.data){
+				node1 = node1.next;
+			}else if((int)node1.data>(int)node2.data){
+				node2 = node2.next;
+			}else{
+				res.add(node1.data);
+				node1 = node1.next;
+				node2 = node2.next;
 			}
-			if(Integer.parseInt(a.data.toString()) > Integer.parseInt(b.data.toString())){
-				res.add(b.data);
-				b = b.next;
-				continue;
-			}
-			if(Integer.parseInt(a.data.toString()) < Integer.parseInt(b.data.toString())){
-				res.add(a.data);
-				a = a.next;
-				continue;
-			}
-		}
-		while(null != a){
-			res.add(a.data);
-			a = a.next;
-		}
-		while(null != b){
-			res.add(b.data);
-			b = b.next;
 		}
 		return res;
 	}
 
-	public String ToString() {
+	public String toString() {
 		LinkedListIterator iter = this.iterator();
 		StringBuilder sb = new StringBuilder();
 		while (iter.hasNext()) {

diff --git a/group24/330657387/src/main/week01/data_structure/LinkedListTest.java b/group24/330657387/src/main/week01/data_structure/LinkedListTest.java
@@ -71,14 +71,9 @@ public void testIterator() {
 	public void testReverse() {
 		LinkedList l = lists[2];
 		l.reverse();
-		LinkedListIterator iter = l.iterator();
-		StringBuilder sb = new StringBuilder();
-		while (iter.hasNext()) {
-			sb.append(iter.next());
-		}
 		// assertEquals("", sb.toString());
-		// assertEquals("A", sb.toString());
-		assertEquals("EDCBA", sb.toString());
+		// assertEquals("A", l.toString());
+		assertEquals("E->D->C->B->A->null", l.toString());
 
 	}
 
@@ -105,7 +100,7 @@ public void testRemoveByIndex() {
 		try{
 			LinkedList l = lists[2];
 			l.remove(0, 1);
-			System.out.println(l.ToString());
+			System.out.println(l.toString());
 		}catch(Exception e){
 			assertEquals(IndexOutOfBoundsException.class, e.getClass());
 		}
@@ -155,7 +150,7 @@ public void testSubtract() {
 		l.add(66);
 		try{
 			list.subtract(l);
-			System.out.println(list.ToString());
+			System.out.println(list.toString());
 		}catch(Exception e){
 			assertEquals(e.getMessage(), "传入链表为空？");
 		}
@@ -171,7 +166,7 @@ public void testRemoveDuplicateValues() {
 
 		list.removeDuplicateValues();
 
-		System.out.println(list.ToString());
+		System.out.println(list.toString());
 	}
 
 	@Test
@@ -185,11 +180,11 @@ public void testRemoveRange() throws Exception {
 		list.add(77);
 		list.add(88);
 		list.add(99);
-		System.out.println(list.ToString());
+		System.out.println(list.toString());
 
 		try{
 			list.removeRange(50, 80);
-			System.out.println(list.ToString());
+			System.out.println(list.toString());
 		}catch(Exception e){
 			assertEquals(e.getMessage(), "输入有问题！");
 		}
@@ -208,11 +203,11 @@ public void testIntersection() {
 //		list.add(99);
 
 		LinkedList l = new LinkedList();
-		l.add(10);
-//		l.add(30);
-//		l.add(40);
-//		l.add(60);
+		l.add(11);
+		l.add(33);
+//		l.add(44);
+//		l.add(66);
 
-		System.out.println(list.intersection(l).ToString());
+		System.out.println(list.intersection(l).toString());
 	}
 }
diff --git a/group24/330657387/src/main/week03/download/DownloadThread.java b/group24/330657387/src/main/week03/download/DownloadThread.java
@@ -1,5 +1,6 @@
 package main.week03.download;
 
+import java.io.File;
 import java.io.RandomAccessFile;
 import java.util.concurrent.CyclicBarrier;
 
@@ -33,7 +34,7 @@ public void run() {
 					+ "]");
 
 			byte[] data = conn.read(startPos, endPos);
-			//设置文件的读取权限
+			//设置文件的读取权限，每个线程都独立有这个实例，这样，多线程读写同一文件就没问题。
 			RandomAccessFile file = new RandomAccessFile(localFile, "rw");
 
 			file.seek(startPos);
@@ -47,9 +48,9 @@ public void run() {
 			barrier.await(); // 等待别的线程完成
 
 		} catch (Exception e) {
+			//如果线程出错了，无法await，怎么处理？
 			e.printStackTrace();
-
-		}
+		} finally{}//这块里应该写close的
 
 	}
 }
diff --git a/group24/330657387/src/main/week03/download/FileDownloader.java b/group24/330657387/src/main/week03/download/FileDownloader.java
@@ -58,7 +58,7 @@ public void run() {
 
 			int length = conn.getContentLength();
 
-			//确保文件里有足够的空间？
+			//确保文件里有足够的空间，就先创建空文件。
 			createPlaceHolderFile(this.filePath, length);
 
 			//每个线程的读取区间

diff --git a/group24/330657387/src/main/week03/download/impl/ConnectionImpl.java b/group24/330657387/src/main/week03/download/impl/ConnectionImpl.java
@@ -12,7 +12,8 @@
 import main.week03.download.api.Connection;
 import main.week03.download.api.ConnectionException;
 
-public class ConnectionImpl implements Connection {
+//包级可见，是保护措施
+class ConnectionImpl implements Connection {
 
 	URL url;
 	static final int BUFFER_SIZE = 1024;
@@ -29,13 +30,15 @@ public ConnectionImpl(String _url) throws ConnectionException {
 	@Override
 	public byte[] read(int startPos, int endPos) throws IOException {
 		int totalLen = endPos - startPos + 1;
-
+		
 		//是URLConnection的子类，负责http协议的链接
 		HttpURLConnection conn = (HttpURLConnection) url.openConnection();
-		conn.setRequestProperty("Range", "bytes=" + startPos + "-" + endPos);
-
 		InputStream inputStream = conn.getInputStream();
 
+		//客户端可以在请求里放置参数，设置接收数据区间
+		//代替了is.skip(),但是is.skip里有read，所以是边读边移动下标的，和本程序意图相违背。
+		conn.setRequestProperty("Range", "bytes=" + startPos + "-" + endPos);
+
 		byte[] buffer = new byte[BUFFER_SIZE];
 
 		//输出流

diff --git a/group24/330657387/src/main/week03/download/impl/ConnectionManagerImpl.java b/group24/330657387/src/main/week03/download/impl/ConnectionManagerImpl.java
@@ -4,6 +4,7 @@
 import main.week03.download.api.ConnectionException;
 import main.week03.download.api.ConnectionManager;
 
+//返回接口，是对实现的一种隐蔽
 public class ConnectionManagerImpl implements ConnectionManager {
 
 	@Override

diff --git a/group24/330657387/src/main/week03/download/test.jpg b/group24/330657387/src/main/week03/download/test.jpg