使用 C、C++ 或 Java 以编程方式获取 Java 和 Flash 的版本号

Programmatically getting Version number of Java and Flash using C, C++, or Java

本文关键字:Java 获取 Flash 版本号 方式 C++ 使用 编程      更新时间:2023-10-16

我想查找计算机上安装的当前版本的Java的版本号,以及安装在任何具有闪存的给定Web浏览器上的当前版本的Flash。有没有办法使用 Java、C 或 C++ 来做到这一点?如果是这样,我应该研究哪个类/库?

如果你在Java中

    System.out.println(System.getProperty("java.version"));
    System.out.println(System.getProperty("java.vendor"));
    System.out.println(System.getProperty("java.vm.name"));

输出

1.7.0_03
Oracle Corporation
Java HotSpot(TM) Client VM

还有更多关于Java的道具

    for(Map.Entry e  : System.getProperties().entrySet()) {
        if (((String)e.getKey()).startsWith("java")) {
            System.out.println(e);
        }
    }

.

java.runtime.name=Java(TM) SE Runtime Environment
java.vm.version=22.1-b02
java.vm.vendor=Oracle Corporation
java.vendor.url=http://java.oracle.com/
java.vm.name=Java HotSpot(TM) Client VM
java.vm.specification.name=Java Virtual Machine Specification
java.runtime.version=1.7.0_03-b05
....

至于其他语言,我认为您可以通过从应用程序运行%JAVA_HOME%/java -version,读取输出来做到这一点

java version "1.7.0_03"
Java(TM) SE Runtime Environment (build 1.7.0_03-b05)
Java HotSpot(TM) Client VM (build 22.1-b02, mixed mode, sharing)

或者你可以像上面这样纠正一个JavaProps应用程序,像%JAVA_HOME%/java JavaProps一样运行它并读取输出

从 C/C++ 检测 Java 版本可能很棘手,问题是没有标准 API 可用于获取已安装的 JRE 属性。一种方法是创建一个调用java -version并从此进程获取输出的子进程(您也可以使子进程写入特定文件,然后从中检索数据),然后解析它并获取版本。

以下是我前段时间做的 Windows .exe 启动器例程的修改版本,它使用了我刚才解释的内容(为 java -version 创建子进程,使子进程写入临时文件,打开文件并读取其内容,解析版本):

void printJVMVersion() { 
    STARTUPINFO si;
    PROCESS_INFORMATION pi;
    size_t sizeOfStartupInfo = sizeof(STARTUPINFO);
    ZeroMemory(&si, sizeOfStartupInfo);
    si.cb = sizeOfStartupInfo;
    SECURITY_ATTRIBUTES sa = { sizeof(sa) };    // Open files in inheritable mode
    sa.bInheritHandle = TRUE;                   // Allow inheritance
    sa.lpSecurityDescriptor = NULL;             // Handles to the child process
    si.dwFlags = STARTF_USESTDHANDLES;
    const std::string DEFAULT_TEMP_FILE_NAME = "temp_file.txt";
    const size_t MAX_PATH = 256;
    char buffer[MAX_PATH];
    char tempPathBuffer[MAX_PATH];
    GetTempPath(MAX_PATH, tempPathBuffer);
    std::string file_name;
    if ( GetTempFileName(tempPathBuffer, "some_random_prefix", 0, buffer) != 0 ) { 
        file_name = std::string(buffer);
    } else {
        file_name = DEFAULT_TEMP_FILE_NAME;
    }
    si.hStdError = CreateFileA(file_name.c_str(), GENERIC_WRITE, FILE_SHARE_READ, &sa, CREATE_ALWAYS, 0, NULL);
    si.hStdOutput = CreateFileA(file_name.c_str(), GENERIC_WRITE, FILE_SHARE_READ, &sa, CREATE_ALWAYS, 0, NULL);
    if (si.hStdOutput == NULL) {
        MessageBox(NULL, "Error checking for the installed Java Virtual Machine, operation aborted", "Launching", MB_ICONERROR | MB_OK);
        return false;
    }
    if (!CreateProcessA(NULL, "java -version", NULL, NULL, true, 0, NULL, NULL, &si, &pi)) {
        MessageBox(NULL, "It appears that neither you have the Java Virtual Machine installed on your system nor its properly configured", "Launching", MB_ICONERROR | MB_OK);
        ErrorExit("CreateProcessA");
        return false;
    }
    WaitForSingleObject( pi.hProcess, INFINITE );
    if( si.hStdError ) {
        CloseHandle( si.hStdError );
    }
    if( si.hStdOutput ) {
        CloseHandle( si.hStdOutput );
    }
    // "Parse" the txt file
    std::ifstream ifs(file_name.c_str());
    std::string line;
    int versionIndex = 0;
    int value[2];
    value[0] = value[1] = 0;
    while (std::getline(ifs, line)) {
        const std::string JAVA_VERSION_STRING = "java version ";
        size_t index = line.find(JAVA_VERSION_STRING.c_str());
        if (index != std::string::npos) { 
            // get either the 1.X.X or 2.X.X
            std::string version = line.substr(JAVA_VERSION_STRING.size());
            std::string::iterator ite = version.begin();
            std::string::iterator end = version.end();
            std::string tmp = "";
            for (; ite != end; ++ite) { 
                char c = *ite;
                if (isdigit(c)) { 
                    tmp += c;
                } else if (c == '.') {
                    value[versionIndex] = atoi(tmp.c_str());
                    versionIndex++;
                    tmp = "";
                    // If we have, version, major and minor, then another set of digits is unnecessary
                    if (versionIndex == 2) 
                        break;
                }
            }
            std::cout << "detected java version: " << (value[0]) << ", " << (value[1]) << std::endl;
        }
    }
    // Delete the temp file
    DeleteFile(file_name.c_str());
}   

希望这可以有任何帮助