无论是日常编码，还是业务涉及，能够优雅的表达思想，提高代码简洁度，阅读性都是一种能力，总结一下优雅的做法
优雅的关闭流
java7 try with resource，针对实现了AutoCloseable接口的类，都可优雅的关闭流，从而舍弃finally关闭
try catch finally
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| BufferedReader in = null;
try {
....
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if (in != null) {
in.close();
}
} catch (Exception e2) {
e2.printStackTrace();
}
}
try winth resource
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| try (final BufferedReader in = new BufferedReader(new InputStreamReader((new URL(url + "?" + param)).openConnection().getInputStream()));PrintWriter out =new PrintWriter(response.getWriter())){
...
}catch{
}
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Netty 优雅的关闭流程
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shutdownGracefully()
Lambda表达式
list求交集
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List collect = list1.stream().filter(list2::contains).collect(Collectors.toList());
设计模式代替if else,策略模式，模板模式
代码整洁度，例如多注入service，按着高矮胖瘦排列，视觉舒适，controller求求你别写业务代码了
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| public List getRandomList(List<?> paramList,int count){
if(count==0){
return null;
}
Random random=new Random();
List<Integer> tempList=new ArrayList<>();//临时存放产生的list索引，去除重复的索引
List newList=new ArrayList();//生成新的list集合
int temp=0;
if(count<=1){//如果数据小于1，取一条数据
temp = random.nextInt(paramList.size());
newList.add(paramList.get(temp));
}else {
for(int i=0;i<Math.ceil(count);i++){
temp=random.nextInt(paramList.size());//初始化一个随机数，将产生的随机数作为被抽list的索引
if(!tempList.contains(temp)){//判断随机抽取的随机数
tempList.add(temp);
newList.add(paramList.get(temp));
}
else{
i--;
}
}
}
return newList;
}
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优雅判空
个人喜欢Assert判空，至于java8的Optional并没体会到优雅之处，日常StringUtils，Collections，isNoBlank等，
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| public String testOptional(Test test) {
return Optional.ofNullable(test).flatMap(Test::getTest3)
.flatMap(Test3::getTest2)
.map(Test2::getInfo)
.orElse("");
}
看起来挺优雅，但日常没体会到
还有日常常用的instanceof
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| else if (f instanceof TreeBin) {
validated = true;
TreeBin<K,V> t = (TreeBin<K,V>)f;
TreeNode<K,V> r, p;
if ((r = t.root) != null &&
(p = r.findTreeNode(hash, key, null)) != null) {
V pv = p.val;
if (cv == null || cv == pv ||
(pv != null && cv.equals(pv))) {
oldVal = pv;
if (value != null)
p.val = value;
else if (t.removeTreeNode(p))
setTabAt(tab, i, untreeify(t.first));
}
}
}
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