Question

如果我把我的java文件放在一个包中（比如jni / test /），我在执行时会遇到致命的错误。但是，如果我不把文件放在一个包中，一切正常。

拥有套餐时

javac jni/test/Main.java 
javah -jni jni.test.Main
g++ -shared -o libfoo.so -I/usr/lib/jvm/java-7-openjdk-i386/include -I/usr/lib/jvm/java-7-openjdk-i386/include/linux Main.cpp 
java -Djava.library.path=. jni/test/Main

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0xb6c1ce3c, pid=3704, tid=3060386624
#
# JRE version: 7.0_25-b30
# Java VM: OpenJDK Server VM (23.7-b01 mixed mode linux-x86 )
# Problematic frame:
# V  [libjvm.so+0x436e3c]  get_method_id(JNIEnv_*, _jclass*, char const*, char const*, bool, Thread*) [clone .isra.106]+0x7c
#
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
# An error report file with more information is saved as:
# /home/idle/workspace/JNITest/src/hs_err_pid3704.log
#
# If you would like to submit a bug report, please include
# instructions on how to reproduce the bug and visit:
#   https://bugs.launchpad.net/ubuntu/+source/openjdk-7/
#
Aborted

没有套餐时

javac Main.java
javah -jni Main
g++ -shared -o libfoo.so -I/usr/lib/jvm/java-7-openjdk-i386/include -I/usr/lib/jvm/java-7-openjdk-i386/include/linux Main.cpp 
java -Djava.library.path=. Main

//This executes fine

我有2个java类

public class Animal {
    public String name = null;
    public int age = 0;
}

public class Main {    
    public native Animal nativeFoo();    

    static {
        System.loadLibrary("foo");
    }        

    public void print () {
        Animal a = nativeFoo();
        System.out.println(a.name + " " + a.age);
    }

    public static void main(String[] args) {
    (new Main()).print();
    }
}

c ++部分

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class Main */

#ifndef _Included_Main
#define _Included_Main
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     Main
 * Method:    nativeFoo
 * Signature: ()LAnimal;
 */

//if the java file in a package
//JNIEXPORT jobject JNICALL Java_jni_test_Main_nativeFoo (JNIEnv *env, jobject obxj)

JNIEXPORT jobject JNICALL Java_Main_nativeFoo
  (JNIEnv *, jobject);

#ifdef __cplusplus
}
#endif
#endif

cpp文件

#include "Main.h"
//if the java file in a package
//JNIEXPORT jobject JNICALL Java_jni_test_Main_nativeFoo (JNIEnv *env, jobject obxj)

JNIEXPORT jobject JNICALL Java_Main_nativeFoo (JNIEnv *env, jobject obxj){
    jclass animal = env->FindClass("Animal");
    jmethodID cons = env->GetMethodID(animal, "<init>", "()V");
    jobject obj = env->NewObject(animal, cons);

    jfieldID age = env->GetFieldID(animal, "age", "I");
    jfieldID name = env->GetFieldID(animal, "name", "Ljava/lang/String;");

    env->SetObjectField(obj, name, env->NewStringUTF("awww"));
    env->SetIntField(obj, age, 23);
    return obj;
}

Answer 1

基于错误，即通过get_method_id(JNIEnv_*, _jclass*, char const*, char const*, bool, Thread*)调用env->GetMethodID()时，您的jclass变量animal为空。

FindClass调用失败，因为它无法找到“Animal”类。

验证您的类名和包定义是否正确。

请参阅similar question answered here with the same sigsegv

有包时JNI致命错误

1 个答案: