实际上，我已经在 android 模拟器中对 server.c 和 client.c 进行了测试（ps：它们都成功运行并使用 android 通用交叉编译器编译）。然后我更进一步，我重写了客户端-side通过jni。但是，在这种情况下，客户端无法连接到服务器端，尽管新客户端与client.c非常相似。经过搜索，有人提到权限很重要。但是，当我添加 <uses-permission android:name="android.permission.INTERNET" />（ps：此标签在应用程序标签之外）时，问题仍然存在。正如 logcat 所显示的，java 代码实际上调用了 c 方法，但是，为什么它的行为与 client.c 不同呢？任何想法都会让我受益匪浅。提前致谢！
服务器.c：
/* Make the necessary includes and set up the variables. */
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <sys/un.h>
#include <unistd.h>
#include <stdlib.h>
int main()
{
int server_sockfd, client_sockfd;
int server_len, client_len;
struct sockaddr_un server_address;
struct sockaddr_un client_address;
/* Remove any old socket and create an unnamed socket for the server. */
unlink("server_socket");
server_sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
/* Name the socket. */
server_address.sun_family = AF_UNIX;
strcpy(server_address.sun_path, "server_socket");
server_len = sizeof(server_address);
bind(server_sockfd, (struct sockaddr *)&server_address, server_len);
/* Create a connection queue and wait for clients. */
listen(server_sockfd, 5);
while(1) {
char ch;
printf("server waiting\n");
/* Accept a connection. */
client_len = sizeof(client_address);
client_sockfd = accept(server_sockfd,
(struct sockaddr *)&client_address, &client_len);
/* We can now read/write to client on client_sockfd. */
read(client_sockfd, &ch, 1);
ch++;
write(client_sockfd, &ch, 1);
close(client_sockfd);
}
}
客户端.c：
/* Make the necessary includes and set up the variables. */
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <sys/un.h>
#include <unistd.h>
#include <stdlib.h>
int main()
{
int sockfd;
int len;
struct sockaddr_un address;
int result;
char ch = 'A';
/* Create a socket for the client. */
sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
/* Name the socket, as agreed with the server. */
address.sun_family = AF_UNIX;
strcpy(address.sun_path, "server_socket");
len = sizeof(address);
/* Now connect our socket to the server's socket. */
result = connect(sockfd, (struct sockaddr *)&address, len);
if(result == -1) {
perror("oops: client1");
exit(1);
}
/* We can now read/write via sockfd. */
write(sockfd, &ch, 1);
read(sockfd, &ch, 1);
printf("char from server = %c\n", ch);
close(sockfd);
exit(0);
}
java代码：包gz.kaiwii；
public class NSocket {
static{
System.loadLibrary("NSocket");
}
public native void start();
}
本机代码：
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
#include <android/log.h>
#include <android/bitmap.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <sys/un.h>
#include <unistd.h>
#include <stdlib.h>
#define LOG_TAG "NSocket"
#define LOGI(...) __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)
#define LOGE(...) __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)
JNIEXPORT void JNICALL Java_gz_kaiwii_NSocket_start
(JNIEnv * env, jobject object){
LOGI("JNICALL Java_gz_kaiwii_NSocket_start is called!");
int sockfd;
int len;
struct sockaddr_un address;
int result;
char ch = 'A';
/* Create a socket for the client. */
LOGI(" Create a socket for the client!");
sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
if(sockfd==-1){
LOGE("create socket error!!!!!");
}
/* Name the socket, as agreed with the server. */
address.sun_family = AF_UNIX;
strcpy(address.sun_path, "server_socket");
len = sizeof(address);
/* Now connect our socket to the server's socket. */
result = connect(sockfd, (struct sockaddr *)&address, len);
LOGI(" Now connect our socket to the server's socket.");
if(result == -1) {
LOGE("connect error!");
exit(1);
}
/* We can now read/write via sockfd. */
write(sockfd, &ch, 1);
read(sockfd, &ch, 1);
/*
printf("char from server = %c\n", ch);
*/
LOGI("char from server = %c\n", ch);
close(sockfd);
}
日志猫：
