ProcessBuilder not outputting the correct output
up vote
0
down vote
favorite
private void printNumberOfRecords(){
try {
ProcessBuilder builder = new ProcessBuilder(
"/bin/sh", "-c",
"grep", ""target-word"", localFileName, "|", "wc", "-l");
Process p = builder.start();
p.waitFor();
BufferedReader br=new BufferedReader(
new InputStreamReader(
p.getInputStream()));
String line;
while(( line = br.readLine()) != null ) {
System.out.println(line);
}
}
catch( Exception e ) {
e.printStackTrace();
}
}
So I have the following code. The reads a file and counts the number of occurrences of a target word and prints the count. But when I run this function I don't see anything being printed.
java processbuilder
edited Nov 12 at 20:15
Aubin
11.1k63964
asked Nov 12 at 20:03
Aditya
5141521
add a comment |
up vote
0
down vote
favorite
private void printNumberOfRecords(){
try {
ProcessBuilder builder = new ProcessBuilder(
"/bin/sh", "-c",
"grep", ""target-word"", localFileName, "|", "wc", "-l");
Process p = builder.start();
p.waitFor();
BufferedReader br=new BufferedReader(
new InputStreamReader(
p.getInputStream()));
String line;
while(( line = br.readLine()) != null ) {
System.out.println(line);
}
}
catch( Exception e ) {
e.printStackTrace();
}
}
So I have the following code. The reads a file and counts the number of occurrences of a target word and prints the count. But when I run this function I don't see anything being printed.
java processbuilder
edited Nov 12 at 20:15
Aubin
11.1k63964
asked Nov 12 at 20:03
Aditya
5141521
2
1) Perhaps output is printed tostderr, notstdout. Addbuilder.redirectErrorStream(true)before callingstart(). --- 2) Don't callp.waitFor()until after you've read the output, otherwise your code may deadlock. --- 3) Use try-with-resources to correctly close the reader.
– Andreas
Nov 12 at 20:10
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
private void printNumberOfRecords(){
try {
ProcessBuilder builder = new ProcessBuilder(
"/bin/sh", "-c",
"grep", ""target-word"", localFileName, "|", "wc", "-l");
Process p = builder.start();
p.waitFor();
BufferedReader br=new BufferedReader(
new InputStreamReader(
p.getInputStream()));
String line;
while(( line = br.readLine()) != null ) {
System.out.println(line);
}
}
catch( Exception e ) {
e.printStackTrace();
}
}
So I have the following code. The reads a file and counts the number of occurrences of a target word and prints the count. But when I run this function I don't see anything being printed.
java processbuilder
edited Nov 12 at 20:15
Aubin
11.1k63964
asked Nov 12 at 20:03
Aditya
5141521
private void printNumberOfRecords(){
try {
ProcessBuilder builder = new ProcessBuilder(
"/bin/sh", "-c",
"grep", ""target-word"", localFileName, "|", "wc", "-l");
Process p = builder.start();
p.waitFor();
BufferedReader br=new BufferedReader(
new InputStreamReader(
p.getInputStream()));
String line;
while(( line = br.readLine()) != null ) {
System.out.println(line);
}
}
catch( Exception e ) {
e.printStackTrace();
}
}
So I have the following code. The reads a file and counts the number of occurrences of a target word and prints the count. But when I run this function I don't see anything being printed.
java processbuilder
java processbuilder
edited Nov 12 at 20:15
Aubin
11.1k63964
asked Nov 12 at 20:03
Aditya
5141521
edited Nov 12 at 20:15
Aubin
11.1k63964
asked Nov 12 at 20:03
Aditya
5141521
edited Nov 12 at 20:15
Aubin
11.1k63964
edited Nov 12 at 20:15
Aubin
11.1k63964
edited Nov 12 at 20:15
Aubin
11.1k63964
11.1k63964
asked Nov 12 at 20:03
Aditya
5141521
asked Nov 12 at 20:03
Aditya
5141521
asked Nov 12 at 20:03
Aditya
5141521
5141521
2
1) Perhaps output is printed tostderr, notstdout. Addbuilder.redirectErrorStream(true)before callingstart(). --- 2) Don't callp.waitFor()until after you've read the output, otherwise your code may deadlock. --- 3) Use try-with-resources to correctly close the reader.
– Andreas
Nov 12 at 20:10
add a comment |
2
1) Perhaps output is printed tostderr, notstdout. Addbuilder.redirectErrorStream(true)before callingstart(). --- 2) Don't callp.waitFor()until after you've read the output, otherwise your code may deadlock. --- 3) Use try-with-resources to correctly close the reader.
– Andreas
Nov 12 at 20:10
2
2
1) Perhaps output is printed to
stderr, not stdout. Add builder.redirectErrorStream(true) before calling start(). --- 2) Don't call p.waitFor() until after you've read the output, otherwise your code may deadlock. --- 3) Use try-with-resources to correctly close the reader.– Andreas
Nov 12 at 20:10
1) Perhaps output is printed to
stderr, not stdout. Add builder.redirectErrorStream(true) before calling start(). --- 2) Don't call p.waitFor() until after you've read the output, otherwise your code may deadlock. --- 3) Use try-with-resources to correctly close the reader.– Andreas
Nov 12 at 20:10
add a comment |
1 Answer
1
active
oldest
votes
up vote
0
down vote
accepted
Your code ask Java to wait until the subprocess sh end without reading the stream. When the buffer will be full, the subprocess wait, blocked.
Don't use p.waitFor(); until you read the output. The output stream will be closed when the process end.
To be complete, you have to check the error stream, too.
As Andreas noticed, a try-with-resource will be better.
answered Nov 12 at 20:21
Aubin
11.1k63964
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
accepted
Your code ask Java to wait until the subprocess sh end without reading the stream. When the buffer will be full, the subprocess wait, blocked.
Don't use p.waitFor(); until you read the output. The output stream will be closed when the process end.
To be complete, you have to check the error stream, too.
As Andreas noticed, a try-with-resource will be better.
answered Nov 12 at 20:21
Aubin
11.1k63964
add a comment |
up vote
0
down vote
accepted
Your code ask Java to wait until the subprocess sh end without reading the stream. When the buffer will be full, the subprocess wait, blocked.
Don't use p.waitFor(); until you read the output. The output stream will be closed when the process end.
To be complete, you have to check the error stream, too.
As Andreas noticed, a try-with-resource will be better.
answered Nov 12 at 20:21
Aubin
11.1k63964
add a comment |
up vote
0
down vote
accepted
up vote
0
down vote
accepted
Your code ask Java to wait until the subprocess sh end without reading the stream. When the buffer will be full, the subprocess wait, blocked.
Don't use p.waitFor(); until you read the output. The output stream will be closed when the process end.
To be complete, you have to check the error stream, too.
As Andreas noticed, a try-with-resource will be better.
answered Nov 12 at 20:21
Aubin
11.1k63964
Your code ask Java to wait until the subprocess sh end without reading the stream. When the buffer will be full, the subprocess wait, blocked.
Don't use p.waitFor(); until you read the output. The output stream will be closed when the process end.
To be complete, you have to check the error stream, too.
As Andreas noticed, a try-with-resource will be better.
answered Nov 12 at 20:21
Aubin
11.1k63964
answered Nov 12 at 20:21
Aubin
11.1k63964
answered Nov 12 at 20:21
Aubin
11.1k63964
answered Nov 12 at 20:21
Aubin
11.1k63964
11.1k63964
add a comment |
add a comment |
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2
1) Perhaps output is printed to
stderr, notstdout. Addbuilder.redirectErrorStream(true)before callingstart(). --- 2) Don't callp.waitFor()until after you've read the output, otherwise your code may deadlock. --- 3) Use try-with-resources to correctly close the reader.– Andreas
Nov 12 at 20:10