代码片段

• for循环和迭代器

for (Iterator i = destinations.iterator(); i.hasNext();) {}

ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(arr));

• 在判断一个数组中是否包含某个值的时候，开发者经常这样做：

Set<String> set = new HashSet<String>(Arrays.asList(arr));
return set.contains(targetValue);

推荐使用for循环遍历的形式或者使用Apache Commons类库中提供的ArrayUtils类的contains方法。

思考

public static void add(List list, Object o){
    list.add(o);
}
public static void main(String[] args){
    List<String> list = new ArrayList<String>();
    add(list, 10);
    String s = list.get(0);
}

ArrayList与LinkedList的选择
简而言之，如果有大量的增加删除操作并且没有很多的随机访问元素的操作，应该首先LinkedList。

• ByteBuffer 存取无符号数值

public static short getUnsignedByte(ByteBuffer buff) {
        return (short) (buff.get() & 0xff);
    }
 
    public static short getUnsignedByte(ByteBuffer buff, int position) {
        return (short) (buff.get(position) & (short) 0xff);
    }
 
    public static void putUnsignedByte(ByteBuffer buff, int value) {
        buff.put((byte) (value & 0xff));
    }
 
    public static void putUnsignedByte(ByteBuffer buff, int position, int value) {
        buff.put(position, (byte) (value & 0xff));
    }
 
    // --------------------------------------------
    public static int getUnsignedShort(ByteBuffer buff) {
        return buff.getShort() & 0xffff;
    }
 
    public static int getUnsignedShort(ByteBuffer buff, int position) {
        return buff.getShort(position) & (short) 0xffff;
    }
 
    public static void putUnsignedShort(ByteBuffer buff, int value) {
        buff.putShort((short) (value & 0xffff));
    }
 
    public static void putUnsignedShort(ByteBuffer buff, int position, int value) {
        buff.putShort(position, (short) (value & 0xffff));
    }
 
    // --------------------------------------------
    public static long getUnsignedInt(ByteBuffer buff) {
        return buff.getInt() & 0xffffffffL;
    }
 
    public static long getUnsignedInt(ByteBuffer buff, int position) {
        return buff.getInt(position) & 0xffffffffL;
    }
 
    public static void putUnsignedInt(ByteBuffer buff, int value) {
        buff.putInt((int) (value & 0xffffffffL));
    }
 
    public static void putUnsignedInt(ByteBuffer buff, int position, int value) {
        buff.putInt(position, (int) (value & 0xffff));
    }

NOTE: 原文链接：https://blog.csdn.net/abc_key/article/details/31376901