Java BufferedWriter file content is empty

Question

I want to create One file with .cfg extension and content of this file must be in below format

define host {
    host_name                       test.testing.local
    alias                           Server 1
    address                         192.168.1.111
    check_command                   check-host-alive
    max_check_attempts              10
    check_interval                  5
    retry_interval                  5
    active_checks_enabled           1
    passive_checks_enabled          1
    check_period                    24x7
    register                        1
}

For this I am using below code

@POST
@Consumes("application/x-www-form-urlencoded")
@Path("/addNewHost")
public Response AddNewHost(String json) {
    JSONObject returnJson = new JSONObject();

    try {
        JSONObject innerJsonObj = new JSONObject(json);
        HostObj hostObj = new HostObj();
        hostObj.hostname = innerJsonObj.getString("hostname");
        hostObj.ipaddress = innerJsonObj.getString("ipaddress");
        hostObj.alias = innerJsonObj.getString("alias");
        hostObj.check_command = innerJsonObj.getString("check_command");
        hostObj.notification_period = innerJsonObj.getString("notification_period");
        hostObj.max_check_attempts = innerJsonObj.getInt("max_check_attempts");
        hostObj.active_checks_enabled = innerJsonObj.getInt("active_checks_enabled");
        hostObj.passive_checks_enabled = innerJsonObj.getInt("passive_checks_enabled");
        hostObj.register = innerJsonObj.getBoolean("register");
        hostObj.chIntervalInMinutes = innerJsonObj.getInt("chIntervalInMinutes");
        hostObj.retryIntervalInMinutes = innerJsonObj.getInt("retryIntervalInMinutes");
        hostObj.contact_groups = innerJsonObj.getString("contact_groups");
        hostObj.check_period = innerJsonObj.getString("check_period");

        String filename = hostObj.ipaddress.replace(".", "");
        Properties propFile = LoadProp.getProperties();
        BufferedWriter writer = Files.newBufferedWriter(Paths.get(propFile.getProperty(Constants.filepath) + filename + ".cfg"));
        writer.write("define host {\n");
        writer.write("\thost_name\t" + hostObj.hostname + "\n");
        writer.write("\talias\t" + hostObj.alias + "\n");
        writer.write("\taddress\t" + hostObj.ipaddress + "\n");
        writer.write("\tcheck_command\t" + hostObj.check_command + "\n");
        writer.write("\tmax_check_attempts\t" + hostObj.max_check_attempts + "\n");
        writer.write("\tcheck_interval\t" + hostObj.chIntervalInMinutes + "\n");
        writer.write("\tretry_interval\t" + hostObj.retryIntervalInMinutes + "\n");
        writer.write("\tactive_checks_enabled\t" + hostObj.active_checks_enabled + "\n");
        writer.write("\tpassive_checks_enabled\t" + hostObj.passive_checks_enabled + "\n");
        writer.write("\tcheck_period\t" + hostObj.check_period + "\n");
        writer.write("\tregister\t" + hostObj.register + "\n}");

        returnJson.put("success", true);
    } catch (Exception e) {
        JSONObject errorJson = new JSONObject();
        errorJson.put("success", false);
        errorJson.put("error", errorMsg);
        return Response.ok(errorJson.toString()).header("Access-Control-Allow-Origin", "*").build();
    }

    return Response.ok(returnJson.toString()).header("Access-Control-Allow-Origin", "*").build();
}

But problem is that when I run this, my file is created with empty data. So please help me to fix this issue.

I am using Java with Eclipse Mars 1.

Use the try-with-resources statement to make sure you **always** close your writer. — JB Nizet, Jan 09 '17 at 07:36
Did you notice that your Eclipse told you about the problem in a warning? — Holger, Jan 09 '17 at 10:24
Sure, and I suppose, if you look into the documentation, you’ll find out how to do that. But where’s the connection to my previous comment that causes you to ask *me*? — Holger, Jan 09 '17 at 11:31
That doesn’t stop people from posting further notes, like that if you cared about the warnings of your IDE, most notably the one telling you that you should close resources, you never had the problem in the first place. Regardless of whether you accepted the answer or not, it’s a poor answer, as you should follow [JB Nizet’s advice](http://stackoverflow.com/questions/41543016/java-bufferedwriter-file-content-is-empty?noredirect=1#comment70290732_41543016) and use [the try-with-resources statement](https://docs.oracle.com/javase/8/docs/technotes/guides/language/try-with-resources.html) instead. — Holger, Jan 09 '17 at 11:55
@Holger If I remove writer.flush(); writer.close(); than I did not get any warning in my Eclipse Mars 1. — user3441151, Jan 09 '17 at 13:50
Check your [settings. The default is to warn you](http://help.eclipse.org/neon/topic/org.eclipse.jdt.doc.user/reference/preferences/java/compiler/ref-preferences-errors-warnings.htm#resource-leak). See also [“Avoiding resource leaks”](http://help.eclipse.org/neon/index.jsp?topic=%2Forg.eclipse.jdt.doc.user%2Ftasks%2Ftask-avoiding_resource_leaks.htm)… — Holger, Jan 09 '17 at 13:55
@Holger Yes you right. I resolved my issue by using "try (BufferedWriter writer = Files.newBufferedWriter(Paths.get(propFile.getProperty(Constants.filepath) + filename + ".cfg"))) { .... }" — user3441151, Jan 09 '17 at 14:39
@Holger I think that is the correct answer as you suggest me. Right? — user3441151, Jan 09 '17 at 14:41

score 2 · Answer 1 · answered Jan 09 '17 at 07:39

2

You need to flush and close the writer by

writer.flush();
writer.close();

answered Jan 09 '17 at 07:39

Aimee Borda

842
2
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4

Closing the writer will flush it, in fact. – JB Nizet Jan 09 '17 at 07:41
@JBNizet You can see that I am using \t \n in my code. So is there any other simple way to generate file in my format? – user3441151 Jan 09 '17 at 08:16

Java BufferedWriter file content is empty

1 Answers1