java - 使用 JNI 在 .jar 中查找 Java 类

Question

我正在编写一个程序，我在其中使用 JNI 从 C++ 代码调用 Java 函数。如果我直接使用 .class 文件，我的程序运行良好，但是当我将它添加到 jar 文件时，FindClass 失败。例如，这很好用

    std::string stdOpt = "-Djava.class.path=<path_to_jar>/dependency.jar;<path_to_class>";

    boost::scoped_array<char> opt(new char[stdOpt.size() + 1]);
    std::copy(stdOpt.begin(), stdOpt.end(), opt.get());
    opt[stdOpt.size()] = '\0';
    options[0].optionString = opt.get();

    JavaVMInitArgs vm_args;
    memset(&vm_args, 0, sizeof(vm_args));
    vm_args.version = JNI_VERSION_1_6;
    vm_args.nOptions = 1;
    vm_args.options = options;
    long status = JNI_CreateJavaVM(&m_pJavaVirtualMachine, (void**)&m_pJavaEnvironment, &vm_args);
    if (status != JNI_OK)
        throw std::logic_error("Cannot start Java Virtual Machine");

    m_class = m_pJavaEnvironment->FindClass("MyClass");
    if(m_class == 0)
        throw std::logic_error("Cannot find Java class");

但是这个失败了

    std::string stdOpt = "-Djava.class.path=<path_to_jar>/dependency.jar;<path_to_jar>/myjar.jar";

    boost::scoped_array<char> opt(new char[stdOpt.size() + 1]);
    std::copy(stdOpt.begin(), stdOpt.end(), opt.get());
    opt[stdOpt.size()] = '\0';
    options[0].optionString = opt.get();

    JavaVMInitArgs vm_args;
    memset(&vm_args, 0, sizeof(vm_args));
    vm_args.version = JNI_VERSION_1_6;
    vm_args.nOptions = 1;
    vm_args.options = options;
    long status = JNI_CreateJavaVM(&m_pJavaVirtualMachine, (void**)&m_pJavaEnvironment, &vm_args);
    if (status != JNI_OK)
        throw std::logic_error("Cannot start Java Virtual Machine");

    m_class = m_pJavaEnvironment->FindClass("MyClass");    //m_class=NULL
    if(m_class == 0)
        throw std::logic_error("Cannot find Java class");  //throwing exception 

当我尝试从 .jar 获取 Java 类时，我应该做些什么？怎么了？有什么想法吗？

Answer 1

如果您的类在包中，请将包包含在对 FindClass 的调用中，而不是类路径中。

 m_class = m_pJavaEnvironment->FindClass( "com/mycompany/mypackage/MyClass" );