java 7中的新功能 [英] New features in java 7

问题描述

将实施java 7中的哪些新功能？
他们现在在做什么？

What new features in java 7 is going to be implemented? And what are they doing now?

推荐答案

Java SE 7 功能和增强功能

这是来自 OpenJDK 7功能页面的Java 7新功能摘要：

Java SE 7 Features and Enhancements from JDK 7 Release Notes

This is the Java 7 new features summary from the OpenJDK 7 features page:

vm  JSR 292: Support for dynamically-typed languages (InvokeDynamic)
        Strict class-file checking
lang    JSR 334: Small language enhancements (Project Coin)
core    Upgrade class-loader architecture
        Method to close a URLClassLoader
        Concurrency and collections updates (jsr166y)
i18n    Unicode 6.0
        Locale enhancement
        Separate user locale and user-interface locale
ionet   JSR 203: More new I/O APIs for the Java platform (NIO.2)
        NIO.2 filesystem provider for zip/jar archives
        SCTP (Stream Control Transmission Protocol)
        SDP (Sockets Direct Protocol)
        Use the Windows Vista IPv6 stack
        TLS 1.2
sec     Elliptic-curve cryptography (ECC)
jdbc    JDBC 4.1
client  XRender pipeline for Java 2D
        Create new platform APIs for 6u10 graphics features
        Nimbus look-and-feel for Swing
        Swing JLayer component
        Gervill sound synthesizer [NEW]
web     Update the XML stack
mgmt    Enhanced MBeans [UPDATED]

Java 1.7中新功能的代码示例

试用资源声明

这个：

Code examples for new features in Java 1.7

Try-with-resources statement

this:

BufferedReader br = new BufferedReader(new FileReader(path));
try {
   return br.readLine();
} finally {
   br.close();
}

成为：

try (BufferedReader br = new BufferedReader(new FileReader(path)) {
   return br.readLine();
}

您可以声明要关闭的多个资源：

You can declare more than one resource to close:

try (
   InputStream in = new FileInputStream(src);
   OutputStream out = new FileOutputStream(dest))
{
 // code
}

数字文字中的下划线

Underscores in numeric literals

int one_million = 1_000_000;

开关中的字符串

Strings in switch

String s = ...
switch(s) {
 case "quux":
    processQuux(s);
    // fall-through

  case "foo":
  case "bar":
    processFooOrBar(s);
    break;

  case "baz":
     processBaz(s);
    // fall-through

  default:
    processDefault(s);
    break;
}

二进制文字

Binary literals

int binary = 0b1001_1001;

改进通用实例创建的类型推断

Improved Type Inference for Generic Instance Creation

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

变为：

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

多个异常捕获

这个：

Multiple exception catching

this:

} catch (FirstException ex) {
     logger.error(ex);
     throw ex;
} catch (SecondException ex) {
     logger.error(ex);
     throw ex;
}

成为：

} catch (FirstException | SecondException ex) {
     logger.error(ex);
    throw ex;
}

SafeVarargs

这个：

SafeVarargs

this:

@SuppressWarnings({"unchecked", "varargs"})
public static void printAll(List<String>... lists){
    for(List<String> list : lists){
        System.out.println(list);
    }
}

变为：

@SafeVarargs
public static void printAll(List<String>... lists){
    for(List<String> list : lists){
        System.out.println(list);
    }
}

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