{"id":9350,"date":"2014-04-11T17:35:55","date_gmt":"2014-04-11T14:35:55","guid":{"rendered":"http:\/\/examples.javacodegeeks.com\/?p=9350"},"modified":"2021-03-18T12:29:31","modified_gmt":"2021-03-18T10:29:31","slug":"java-io-inputstream-example","status":"publish","type":"post","link":"https:\/\/examples.javacodegeeks.com\/java-io-inputstream-inputstream-java-example\/","title":{"rendered":"java.io.InputStream – InputStream Java Example"},"content":{"rendered":"

In this example, we are going to talk about a very important Java class<\/a>, InputStream. If you have even the slightest experience with programming in Java, chances are that you’ve already used InputStream<\/code> in one of your programs, or one of its subclasses, like FileInputStream<\/code> or BufferedInputStream<\/code>.<\/p>\n

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\"InputStream<\/figure>\n<\/div>\n

You see, java io inputstream is an abstract class, that provides all the necessary API methods you can use in order to read data from a source. That source can be anything : a console, a file, a socket, a pipe, and even an array of bytes that resides on memory. The truth is that most of the times, when reading data from source, your program is actually reading a stream of bytes that resides on memory.<\/p>\n

But what you need to know is that a concrete java io inputstream is connected to one of the aforementioned data resources. It’s main purpose is to read data from that source an make them available for manipulation from inside your program.<\/p>\n

1. Simple InputStream Java Examples<\/h2>\n

Ok so let’s see a simple java io inputstream example on how you can read bytes form the console.<\/p>\n

InputStreamExample.java<\/span><\/em><\/p>\n

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package<\/code> com.javacodegeeks.core.io.inputstream;<\/code><\/div>\n
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import<\/code> java.io.IOException;<\/code><\/div>\n
public<\/code> class<\/code> InputStreamExample {<\/code><\/div>\n
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    <\/code>public<\/code> static<\/code> void<\/code> main(String[] args){<\/code><\/div>\n
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        <\/code>try<\/code> {<\/code><\/div>\n
            <\/code>System.out.println(<\/code>\"Available bytes :\"<\/code>+System.in.available());<\/code><\/div>\n
            <\/code>System.out.print(<\/code>\"Write something :\"<\/code>);<\/code><\/div>\n
            <\/code>int<\/code> b = System.in.read();<\/code><\/div>\n
            <\/code>System.out.println(<\/code>\"Available bytes :\"<\/code>+System.in.available());<\/code><\/div>\n
            <\/code>System.out.println(<\/code>\"Input was :\"<\/code>+b);<\/code><\/div>\n
        <\/code>} <\/code>catch<\/code> (IOException e) {<\/code><\/div>\n
            <\/code>\/\/ TODO Auto-generated catch block<\/code><\/div>\n
            <\/code>e.printStackTrace();<\/code><\/div>\n
        <\/code>}   <\/code><\/div>\n
    <\/code>}<\/code><\/div>\n
}<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Let’s clear things up: System.in<\/code> is an InputStream<\/code> that is connected to the standard input. This means that its can be used to read data from the console. In this snippet we’ve used two InputStream<\/code> API methods :<\/p>\n