From deeb6bb7f8527e0c0f9e902026ff28bf1e19d193 Mon Sep 17 00:00:00 2001 From: "handm2018@126.com" Date: Tue, 13 Aug 2019 16:25:36 +0800 Subject: [PATCH 1/2] =?UTF-8?q?InputStream=20=E5=88=9D=E6=AD=A5=E9=98=85?= =?UTF-8?q?=E8=AF=BB?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- src/java/io/InputStream.java | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/java/io/InputStream.java b/src/java/io/InputStream.java index d6702c6..4a1f97a 100644 --- a/src/java/io/InputStream.java +++ b/src/java/io/InputStream.java @@ -162,7 +162,8 @@ public int read(byte b[]) throws IOException { * b.length - off * @see java.io.InputStream#read() * - * 将流中的数据读入，放在byte数组的地off位置的len位置 + * 将流中的数据读入，放在byte数组的第off位置的len位置 + * 该read(b, off, len)方法只是简单地反复调用方法read() */ public int read(byte b[], int off, int len) throws IOException { if (b == null) { @@ -170,6 +171,7 @@ public int read(byte b[], int off, int len) throws IOException { } else if (off < 0 || len < 0 || len > b.length - off) { throw new IndexOutOfBoundsException(); } else if (len == 0) { + // 如果len为零，则不会读取字节并返回0 ; return 0; } From 1dba4fab09bda31cbfff4b814241ef13db32e32e Mon Sep 17 00:00:00 2001 From: handm Date: Fri, 22 Nov 2019 16:18:12 +0800 Subject: [PATCH 2/2] =?UTF-8?q?ArrayList=E6=B3=A8=E9=87=8A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- src/java/util/ArrayList.java | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/src/java/util/ArrayList.java b/src/java/util/ArrayList.java index 5616402..ca90806 100644 --- a/src/java/util/ArrayList.java +++ b/src/java/util/ArrayList.java @@ -25,10 +25,11 @@ package java.util; +import sun.misc.SharedSecrets; + import java.util.function.Consumer; import java.util.function.Predicate; import java.util.function.UnaryOperator; -import sun.misc.SharedSecrets; /** * Resizable-array implementation of the List interface. Implements @@ -110,12 +111,13 @@ public class ArrayList extends AbstractList private static final long serialVersionUID = 8683452581122892189L; /** - * Default initial capacity. + * Default initial capacity. 默认容量 */ private static final int DEFAULT_CAPACITY = 10; /** * Shared empty array instance used for empty instances. + * size=0的空实例对象 */ private static final Object[] EMPTY_ELEMENTDATA = {}; @@ -131,19 +133,20 @@ public class ArrayList extends AbstractList * The capacity of the ArrayList is the length of this array buffer. Any * empty ArrayList with elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA * will be expanded to DEFAULT_CAPACITY when the first element is added. + * 保存ArrayList中数据的数组 */ transient Object[] elementData; // non-private to simplify nested class access /** * The size of the ArrayList (the number of elements it contains). - * + * ArrayList的实际数据的数量 * @serial */ private int size; /** * Constructs an empty list with the specified initial capacity. - * + * 带容量参数的构造 * @param initialCapacity the initial capacity of the list * @throws IllegalArgumentException if the specified initial capacity * is negative @@ -152,6 +155,7 @@ public ArrayList(int initialCapacity) { if (initialCapacity > 0) { this.elementData = new Object[initialCapacity]; } else if (initialCapacity == 0) { + // 1.6版本的是直接初始化一个容量为10的对象，现在是初始化为容量=0的对象 this.elementData = EMPTY_ELEMENTDATA; } else { throw new IllegalArgumentException("Illegal Capacity: "+ @@ -161,6 +165,7 @@ public ArrayList(int initialCapacity) { /** * Constructs an empty list with an initial capacity of ten. + * 空参构造，默认容量=0，1.6版本的默认容量为10 */ public ArrayList() { this.elementData = DEFAULTCAPACITY_EMPTY_ELEMENTDATA; @@ -170,7 +175,7 @@ public ArrayList() { * Constructs a list containing the elements of the specified * collection, in the order they are returned by the collection's * iterator. - * + * 创建一个包含collection的ArrayList * @param c the collection whose elements are to be placed into this list * @throws NullPointerException if the specified collection is null */ @@ -181,7 +186,7 @@ public ArrayList(Collection c) { if (elementData.getClass() != Object[].class) elementData = Arrays.copyOf(elementData, size, Object[].class); } else { - // replace with empty array. + // replace with empty array. 依然将数据为0的情况独立出来，替换为容量=0的对象 this.elementData = EMPTY_ELEMENTDATA; } } @@ -190,6 +195,7 @@ public ArrayList(Collection c) { * Trims the capacity of this ArrayList instance to be the * list's current size. An application can use this operation to minimize * the storage of an ArrayList instance. + * 将当前容量值设为 =实际元素个数 */ public void trimToSize() { modCount++; @@ -204,6 +210,7 @@ public void trimToSize() { * Increases the capacity of this ArrayList instance, if * necessary, to ensure that it can hold at least the number of elements * specified by the minimum capacity argument. + * 确定ArrayList的容量 * * @param minCapacity the desired minimum capacity */