为什么JNI中的GetMethodID函数总是返回0? [英] why the function GetMethodID in JNI always return 0?

问题描述

下面是C ++代码

below is C++ code

jmethodID mid;
jclass cls = env->FindClass( "test/MyTest");

mid = env->GetMethodID(cls, "append","(Ljava/lang/String;I)Ljava/lang/String;");   

mid=env->GetMethodID(cls,"HelloWord","()Ljava/lang/String;");

以下由javap显示

below is display by javap

public test.MyTest(java.lang.String);
  Signature: (Ljava/lang/String;)V
public java.lang.String HelloWord();
  Signature: ()Ljava/lang/String;
public java.lang.String append(java.lang.String, int);
  Signature: (Ljava/lang/String;I)Ljava/lang/String;

下面是Java代码:

below is java code：

public String HelloWord() {
    System.out.println("JAVA-CLASS:MyTest method:HelloWord:" +
helloword);
 
    return helloword;
}
 
//test
public String append(String str, int i)   
{   
    return str + i;   
}

推荐答案

正如我在C ++论坛中所述

As I stated in the C++ forum here[^] I have tried this and it works. I cannot tell from the code you have posted what you are doing wrong.

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