Java 次要/更新版本检查

Question

如何通过shell脚本查看minor/update版本版本。

例如我当前的命令输出

$ java -version
java version "1.8.0_171"

我使用的是 256 AES，需要 java update > 161。我想测试次要版本，如何做。

Answer 1

如果你坚持的话，可以按照这个discussion获取 Java 的主要版本和次要版本并在控制台上打印它。

关于 AES 256，默认情况下 Java 版本 1.8.0_171 已经默认支持 key 大小 > 128。以下是 <JAVA_HOME>/jre/lib/security/java.security 的摘录文件:-

# Cryptographic Jurisdiction Policy defaults
#
# Import and export control rules on cryptographic software vary from
# country to country.  By default, the JDK provides two different sets  of
# cryptographic policy files:
#
#     unlimited:  These policy files contain no restrictions on cryptographic
#                 strengths or algorithms.
#
#     limited:    These policy files contain more restricted cryptographic
#                 strengths, and are still available if your country or
#                 usage requires the traditional restrictive policy.
#
# The JDK JCE framework uses the unlimited policy files by default.
# However the user may explicitly choose a set either by defining the
# "crypto.policy" Security property or by installing valid JCE policy
# jar files into the traditional JDK installation location.  To better
# support older JDK Update releases, the "crypto.policy" property is not
# defined by default.  See below for more information.

要测试具有 256 key 强度的 TLS 连接，您可以使用 SSLPoke程序。使用 javac 编译此程序并按如下方式运行:-

$java -Djavax.net.debug=all SSLPoke microsoft.com 443 | grep 'Cipher Suite: TLS'

如果 SSL 握手和连接成功，则 key 大小 > 128 的密码套件将在控制台打印。