java7的新特性

   1. try (BufferedReader br = new BufferedReader(new FileReader(path)) {  
   2.    return br.readLine();  
   3. }  
   4.   
   5. You can declare more than one resource to close:  
   6.   
   7. try (  
   8.    InputStream in = new FileInputStream(src);  
   9.    OutputStream out = new FileOutputStream(dest))  
  10. {  
  11.  // code  
  12. }  

 

Devoxx 大会结束在几天前结束了，一位与会者 对此次大会的重要内容进行了总结，他提到Java 7的主要变化如下：

1.对collections的支持

   1. List<String> list = new ArrayList<String>();  
   2. list.add("item");  
   3. String item = list.get(0);  
   4.   
   5. Set<String> set = new HashSet<String>();  
   6. set.add("item");  
   7.   
   8. Map<String, Integer> map = new HashMap<String, Integer>();  
   9. map.put("key", 1);  
  10. int value = map.get("key");  

 现在你还可以：

   1. List<String> list = ["item"];  
   2. String item = list[0];  
   3.   
   4. Set<String> set = {"item"};  
   5.   
   6. Map<String, Integer> map = {"key" : 1};  
   7. int value = map["key"];  

 2.自动资源管理

   1. BufferedReader br = new BufferedReader(new FileReader(path));  
   2. try {  
   3.    return br.readLine();  
   4. } finally {  
   5.    br.close();  
   6. }  

 becomes:

   1. try (BufferedReader br = new BufferedReader(new FileReader(path)) {  
   2.    return br.readLine();  
   3. }  
   4.   
   5. You can declare more than one resource to close:  
   6.   
   7. try (  
   8.    InputStream in = new FileInputStream(src);  
   9.    OutputStream out = new FileOutputStream(dest))  
  10. {  
  11.  // code  
  12. }  

 3.对通用实例创建(diamond)的type引用进行了改进

   1. Map<String, List<String>> anagrams = new HashMap<String, List<String>>();  

  becomes:

Map<String, List<String>> anagrams = new HashMap<>(); 

 4.数值可加下划线

   1. int one_million = 1_000_000;  

 5.在switch中可使用string

   1. String s = ...  
   2. switch(s) {  
   3.  case "quux":  
   4.     processQuux(s);  
   5.     // fall-through  
   6.   
   7.   case "foo":  
   8.   case "bar":  
   9.     processFooOrBar(s);  
  10.     break;  
  11.   
  12.   case "baz":  
  13.      processBaz(s);  
  14.     // fall-through  
  15.   
  16.   default:  
  17.     processDefault(s);  
  18.     break;  
  19. }  

 6.二进制文字

   1. int binary = 0b1001_1001;  

 7.简化了可变参数方法的调用

当程序员试图使用一个不可具体化的可变参数并调用一个*varargs* （可变）方法时，编辑器会生成一个“非安全操作”的警告