1,菱形语法(泛型实例化类型自动推断) List<String> list = new ArrayList<>(); // <>这个真的很像菱形 2,在目前版本中,不可具体化的泛型(任意类型)可变参数,在编译时,会在调用处产生警告,JDK7里将这个警告挪到了方法定义处。 变化前: static <T> List<T> asList(T... elements) { ... } static List<Callable<String>> stringFactories() { Callable<String> a, b, c; ... // 警告处 return asList(a, b, c); } static <T> List<T> asList(T... elements) { ... } static List<Callable<String>> stringFactories() { Callable<String> a, b, c; ... // 警告处 return asList(a, b, c); } 变化后: // 警告处 static <T> List<T> asList(T... elements) { ... } static List<Callable<String>> stringFactories() { Callable<String> a, b, c; ... return asList(a, b, c); } // 警告处 static <T> List<T> asList(T... elements) { ... } static List<Callable<String>> stringFactories() { Callable<String> a, b, c; ... return asList(a, b, c); } 3,switch现在可以支持字符串了 String s = ... switch(s) { case "quux": processQuux(s); //没有break,继续往下 case "foo": case "bar": processFooOrBar(s); break; case "baz": processBaz(s); //没有break,继续往下 default: processDefault(s); break; } String s = ... switch(s) { case "quux": processQuux(s); //没有break,继续往下 case "foo": case "bar": processFooOrBar(s); break; case "baz": processBaz(s); //没有break,继续往下 default: processDefault(s); break; } 4,支持二进制语法和单位级别的数字表示方式 // 8位byte byte aByte = (byte)0b00100001; // 16位short short aShort = (short)0b1010000101000101; // 32位int int anInt1 = 0b10100001010001011010000101000101; // 8位byte byte aByte = (byte)0b00100001; // 16位short short aShort = (short)0b1010000101000101; // 32位int int anInt1 = 0b10100001010001011010000101000101; 支持单位级别的数字,提高可读性 long underScores = 9_223_372_036_854_775_807L; // 每三位加一下划线,等同于 9,223,372,036,854,775,807 long underScores = 9_223_372_036_854_775_807L; // 每三位加一下划线,等同于 9,223,372,036,854,775,807 5,从语法层面上支持集合,不再是数组的专利。 final List<Integer> piDigits = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 9]; final Set<Integer> primes = { 2, 7, 31, 127, 8191, 131071, 524287 }; final Map<Integer, String> platonicSolids = { 4 : "tetrahedron", 6 : "cube", 8 : "octahedron", 12 : "dodecahedron", 20 : "icosahedron" }; final List<Integer> piDigits = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 9]; final Set<Integer> primes = { 2, 7, 31, 127, 8191, 131071, 524287 }; final Map<Integer, String> platonicSolids = { 4 : "tetrahedron", 6 : "cube", 8 : "octahedron", 12 : "dodecahedron", 20 : "icosahedron" }; 6,JSR 292 动态类型语言支持 Dynamic x = (动态语言脚本); Object y = x.foo("ABC").bar(42).baz(); Dynamic x = (动态语言脚本); Object y = x.foo("ABC").bar(42).baz(); 7,动态资源管理 在目前版本的java中,当你操作流时,一定会加try..finally以保证出现异常时,流能被正确关闭。 BufferedReader br = new BufferedReader(new FileReader(path)); try { return br.readLine(); } finally { br.close(); } BufferedReader br = new BufferedReader(new FileReader(path)); try { return br.readLine(); } finally { br.close(); } 在JDK7里,你只需要将资源定义在try()里,Java7就会在readLine抛异常时,自动关闭资源。另外,资源类必须实现 Disposable<?> 接口。支持管理多个资源 try (BufferedReader br = new BufferedReader(new FileReader(path)) { return br.readLine(); }
??
?
?
?? 下载地址
????Windows x86 ?http://download.oracle.com/otn-pub/java/jdk/7/jdk-7-windows-i586.exe
?? ?Windows x64 ?http://download.oracle.com/otn-pub/java/jdk/7/jdk-7-windows-x64.exe?
???