共有6个文件/类:mainLaptop、Send、c\u app、StreamTest、make file和美联社文本.
我试图获取在c文件中处理的数据,并将其传递给java文件中的一个变量。以下是本教程的“带字符串的管道”部分:
http://www.jonathanbeard.io/tutorials/CtoJava
1 make StreamTest
2 make c_app
3 java -cp . StreamTest
4 ./c_app
在执行时,我看到“JAVA端!!”然后是终端中c进程的总数、计数和平均值(以及由于我的修改而产生的一些错误)
然后在eclipse中我在eclipse中运行StreamTest
Eclipse输出这个
JAVA SIDE:
[x] Sent ''Leonardo
[x] Sent ''Raphael
[x] Sent ''Donatello
[x] Sent ''Michelangelo
JAVA SIDE:
[x] Sent 'Total: 4953, Integers: 1000, Average: 4.9530'Leonardo
[x] Sent 'Total: 4953, Integers: 1000, Average: 4.9530'Raphael
[x] Sent 'Total: 4953, Integers: 1000, Average: 4.9530'Donatello
[x] Sent 'Total: 4953, Integers: 1000, Average: 4.9530'Michelangelo
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <inttypes.h>
#define DEBUG 0
#define BUFFER 4096
//open ap.txt for text input
static const char* exFile = "ap.txt";
static char inputBuffer[BUFFER];
int main(int argc, const char** argv)
{
FILE *fp = fopen(exFile,"r");
/*check and see if the pointer is null in otherwords see if the memory
location refered to by fp is set...no memory location should be zero
if you want to reference it
Here are some good ways to do this other than the way I did it below:
if(!fp) {do error}
if(fp == NULL) {do error}
and then there's the way I did it below
*/
if(fp == 0){
fprintf(stderr,"Null pointer exception, check file name.\n");
exit(-1);
}
//check and see if an error occured during open
const int err = ferror(fp);
if(err != 0){
/* void perror(const char* err) returns specific error message to string attached. */
const char* errMessage = strcat("Something bad happened while opening file ",exFile);
perror(errMessage);
}
#if (DEBUG == 1)
else{
fprintf(stderr,"Success opening file!!\n");
}
#endif
setbuf(fp,inputBuffer); //set a buffer for input
uint64_t *num = (uint64_t*) malloc(sizeof(uint64_t));
uint64_t total = 0;
uint64_t n = 0;
//test for eof
/*
feof(*fp) - returns a boolean true if at end of file and false otherwise
*/
while(!feof(fp)){
//fscanf returns the number of items it converted using %llu, if it's not equal to 1 we don't want to continue
if(fscanf(fp,"%"PRIu64"",num)!=1)
break; //you could do a lot of stuff here as far as error handling but basically something bad has happened
total+= *num; //add to total the value at memory location num
n++;
#if (DEBUG == 1)
fprintf(stderr,"line number %"PRIu64"\n",n);
#endif
}
free(num);
const double average = (double) total / (double) n;
//close the inputfile
fclose(fp);
//declare our outputfile, use a pipe in this case to a java process
//we open a java process for this process to pipe to, also it is
//technically a bi-directional pipe so we can use any of the modifiers
//like r/w/r+/etc
static const char* outFile = "java -cp . StreamTest";
FILE *fp_out = popen(outFile,"w");
//setbuf(fp_out,outputBuffer);
fprintf(fp_out,"Total: %"PRIu64", Integers: %"PRIu64", Average:
%.4f\n",total,n,average);
/*
int fflush(*fp) pushes any data in the buffer to be written
the return value returns 0 if successful or !=0 if an error
occurs....remember return values in C often equal exceptions
*/
fflush(fp_out);
/* int */
fclose(fp_out);
return 1;
}
这是制作文件
CC ?=gcc
JCC ?= javac
FLAGS ?= -Wall -O2
JFLAGS ?= -g -verbose
all: c_app StreamTest
c_app: c_app.c
$(CC) $(FLAGS) -o c_app c_app.c
StreamTest: StreamTest.java
$(JCC) $(JFLAGS) StreamTest.java $(LIBS)
clean:
rm -f c_app StreamTest.class
这个美联社文本文件只是一堆数字
水流试验
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
public class StreamTest
{
private static final int buffer = 4096;
public static void main(String[] args) throws Exception
{
String pass=null;
InputStream is = null;
BufferedInputStream bis = null;
try
{
bis = new BufferedInputStream(System.in,buffer);
StringBuilder sb = new StringBuilder();
//sb.append((char)bis.read());
while(bis.available() > 0){
sb.append((char)bis.read());
}
pass = sb.toString();
System.out.println("JAVA SIDE: "+pass);
bis.close();
}
catch(IOException ex)
{
}
finally
{
}
//pass = "hi";
mainLaptop.main(pass);
}
}
public class mainLaptop
{
public static void main(String arg) throws Exception
{
//Timing out? change the IP!
String ip="192.168.137.127";
String Pi1Q1="Leonardo";
String Pi1Q2="Raphael";
String Pi2Q3="Donatello";
String Pi2Q4="Michelangelo";
String pass=arg;
Send.send(ip, Pi1Q1, pass);
Send.send(ip, Pi1Q2, pass);
Send.send(ip, Pi2Q3, pass);
Send.send(ip, Pi2Q4, pass);
/* Recv.recv(ip, Pi1Q1);
Recv.recv(ip, Pi1Q2);
Recv.recv(ip, Pi2Q3);
Recv.recv(ip, Pi2Q4);*/
}
}
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
public class Send
{
public static void send(String ip, String Q, String pass) throws
Exception
{
ConnectionFactory factory = new ConnectionFactory();
//set connection info
factory.setHost(ip);
factory.setUsername("test");
factory.setPassword("test");
//create connection
Connection connection = factory.newConnection();
//create channel
Channel channel = connection.createChannel();
//publish message
// int a = 1;
//while (a!=0)
{
channel.queueDeclare(Q, false, false, false, null);
//for(int i=1; i<=2; i++)
{
//String message = pass;
channel.basicPublish("", Q, null, pass.getBytes("UTF-8"));
System.out.println(" [x] Sent '" + pass + "'" + Q);
}
//a--;
}
//SHUT IT ALL DOWN!
channel.close();
connection.close();
}
}
更新流测试
@EJP建议的编辑
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
public class StreamTest{
private static final int buffer = 4096;
static String pass;
public static void main(String[] args)
{
InputStream is = null;
BufferedInputStream bis = null;
BufferedReader bir = null;
try
{
bis = new BufferedInputStream(System.in,buffer);
StringBuilder sb = new StringBuilder();
while ((bir.readLine()) != null)
{
// Do something here. Who knows
}
/*while(bis.available() > 0){
sb.append((char)bis.read());
}*/
/*int b;
while ((b = bis.read()) != -1)
{
// do something with 'b'
sb.append((char)b);
}*/
pass=sb.toString();
System.out.println("JAVA SIDE: "+pass);
bir.close();
bis.close();
}
catch(IOException ex)
{
}
finally{
}
try {
mainLaptop.main(pass);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
