java编译,“没有这样的文件或目录”

aelbi1ox  于 2021-07-03  发布在  Java
关注(0)|答案(1)|浏览(327)

使用jni我试图让c程序在java下工作。问题是。
首先,我创建了java类testcli.java:

public class testcli {

    public native void stdErr();
    public native int cliFromC();

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

    public static void main(String[] args) {

        new testcli().stdErr();
        new testcli().cliFromC();

    }

然后用

javac testcli.java

并用

javah testcli

之后创建librari ctest.c并用

gcc -o libctest.so -shared -I/path/to/jni.h ctest.c -lc

我创建了libctest.so,然后将以下代码添加到bashrc中:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:~/Desktop/project2/thesys/src

当我去打字的时候

java testcli

它告诉我“没有这样的文件或目录”。
我在32位机器上运行java8oracle,xubuntu32位。有什么想法吗?
编辑:在这里添加了ctest.c代码(我想这里可能有一些错误)


# include <jni.h>

# include <stdlib.h>

# include <stdio.h>

# include <errno.h>

# include <string.h>

# include <sys/types.h>

# include <netinet/in.h>

# include <sys/wait.h>

# include <sys/socket.h>

# include <signal.h>

# include <ctype.h>

# include <arpa/inet.h>

# include <netdb.h>

# define PORT 20000

# define LENGTH 512

JNIEXPORT void JNICALL Java_testcli_stdErr
  (JNIEnv *env, jobject jobj)

{
    const char *msg = NULL;

    perror(msg);
    exit(1);
}

JNIEXPORT jint JNICALL Java_testcli_cliFromC
  (JNIEnv *env, jobject jobj)

{
    /* Variable Definition */
    int sockfd; 
    int nsockfd;
    char revbuf[LENGTH]; 
    struct sockaddr_in remote_addr;
    //struct hostent *server; // per la parte scritta da me

    /* Get the Socket file descriptor */
    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
    {
        fprintf(stderr, "ERROR: Failed to obtain Socket Descriptor! (errno = %d)\n",errno);
        exit(1);
    }

    /* Fill the socket address struct */
    remote_addr.sin_family = AF_INET; 
    remote_addr.sin_port = htons(PORT); 

    /*questo lo faccio così perchè localhost è 127.0.0.1, nel caso in cui debba recuperare l'ip dall'hostname uso la parte commentata sopra*/
    inet_pton(AF_INET, "127.0.0.1", &remote_addr.sin_addr); //metto in remote_addr.sin_addr l'indirizzo ip 127.0.0.1 nel formato desiderato

    bzero(&(remote_addr.sin_zero), 8);

    /* Try to connect the remote */
    if (connect(sockfd, (struct sockaddr *)&remote_addr, sizeof(struct sockaddr)) == -1)
    {
        fprintf(stderr, "ERROR: Failed to connect to the host! (errno = %d)\n",errno);
        exit(1);
    }
    else 
        printf("[Client] Connected to server at port %d...ok!\n", PORT);

/* Send File to Server */
    //if(!fork())
    //{
        char* fs_name = "/home/elia/Desktop/project/tesi/PublicKey1";
        char sdbuf[LENGTH]; 
        printf("[Client] Sending %s to the Server... ", fs_name);
        FILE *fs = fopen(fs_name, "r");
        if(fs == NULL)
        {
            printf("ERROR: File %s not found.\n", fs_name);
            exit(1);
        }

        bzero(sdbuf, LENGTH); 
        int fs_block_sz; 
        while((fs_block_sz = fread(sdbuf, sizeof(char), LENGTH, fs)) > 0)
        {
            if(send(sockfd, sdbuf, fs_block_sz, 0) < 0)
            {
                fprintf(stderr, "ERROR: Failed to send file %s. (errno = %d)\n", fs_name, errno);
                break;
            }
            bzero(sdbuf, LENGTH);
        }
        printf("Ok File %s from Client was Sent!\n", fs_name);
    //}
    close (sockfd);
    printf("[Client] Connection lost.\n");
    return (0);

}
dxxyhpgq

dxxyhpgq1#

实际上,一切都很好。错误来自您的 stdErr() 功能,它实际上表明它在工作。我也有同样的错误。为什么会这样?

const char *msg = NULL;

perror(msg);
exit(1);

这将打印程序中导致的最后一个错误。现在,你应该只使用 perror() 如果你的程序真的出错了。否则,它将打印 errno 以前是变量。 errno 可能是由java本身内部的某些东西设置的。它可能一直在寻找某个文件,但它的不存在对java来说不是问题,所以它继续工作。但是 errno 设置为该值并保持该值,这就是程序中打印的内容。
为了证明这一点,我在你的报告中增加了以下内容 testcli.java :

public native void clearErr();

还有我的 main 是:

public static void main(String[] args) {

    new testcli().clearErr();
    new testcli().stdErr();
    new testcli().cliFromC();

}

以及 ctest.c 我补充说:

JNIEXPORT void JNICALL Java_testcli_clearErr
  (JNIEnv *env, jobject jobj)

{
    errno = 0;
}

是吗 javac , javah 以及 gcc 再次运行程序,现在我得到:

Success

请注意,由于 exit()stdErr() .

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