InputStreamReader<\/code> class of the java.io<\/code> package can be used to convert data in bytes into data in characters.<\/p>\n\n\n\nIt extends the abstract class Reader<\/code>.<\/p>\n\n\n\n![\"The](\"https:\/\/cdn.programiz.com\/sites\/tutorial2program\/files\/java-%20inputstreamreader.png\" "\\"Java")
<\/figure>\n\n\n\nThe InputStreamReader<\/code> class works with other input streams. It is also known as a bridge between byte streams and character streams. This is because the InputStreamReader<\/code> reads bytes from the input stream as characters.<\/p>\n\n\n\nFor example, some characters required 2 bytes to be stored in the storage. To read such data we can use the input stream reader that reads the 2 bytes together and converts into the corresponding character.<\/p>\n\n\n\n
\n\n\n\nCreate an InputStreamReader<\/h2>\n\n\n\n
In order to create an InputStreamReader<\/code>, we must import the java.io.InputStreamReader<\/code> package first. Once we import the package here is how we can create the input stream reader.<\/p>\n\n\n\n\/\/ Creates an InputStream\nFileInputStream file = new FileInputStream(String path);\n\n\/\/ Creates an InputStreamReader\nInputStreamReader input = new InputStreamReader(file);\n<\/code><\/pre>\n\n\n\nIn the above example, we have created an InputStreamReader<\/code> named input<\/var> along with the FileInputStream<\/code> named file<\/var>.<\/p>\n\n\n\nHere, the data in the file are stored using some default character encoding.<\/p>\n\n\n\n
However, we can specify the type of character encoding (UTF8<\/strong> or UTF16<\/strong>) in the file as well.<\/p>\n\n\n\n\/\/ Creates an InputStreamReader\n specifying the character encoding\nInputStreamReader input = new InputStreamReader(file, Charset cs);\n<\/code><\/pre>\n\n\n\nHere, we have used the Charset<\/code> class to specify the character encoding in the file.<\/p>\n\n\n\n
\n\n\n\nMethods of InputStreamReader<\/h2>\n\n\n\n
The InputStreamReader<\/code> class provides implementations for different methods present in the Reader<\/code> class.<\/p>\n\n\n\nread() Method<\/h3>\n\n\n\nread()<\/code> – reads a single character from the reader<\/li>read(char[] array)<\/code> – reads the characters from the reader and stores in the specified array<\/li>read(char[] array, int start, int length)<\/code> – reads the number of characters equal to length<\/var> from the reader and stores in the specified array starting from the start<\/var><\/li><\/ul>\n\n\n\nFor example, suppose we have a file named input.txt<\/strong> with the following content.<\/p>\n\n\n\nThis is a line of text inside the file.\n<\/code><\/pre>\n\n\n\nLet’s try to read this file using InputStreamReader<\/code>.<\/p>\n\n\n\nimport java.io.InputStreamReader;\nimport java.io.FileInputStream;\n\nclass Main {\n public static void main(String[] args) {\n\n \/\/ Creates an array of character\n char[] array = new char[100];\n\n try {\n \/\/ Creates a FileInputStream\n FileInputStream file = new FileInputStream(\"input.txt\");\n\n \/\/ Creates an InputStreamReader\n InputStreamReader input = new InputStreamReader(file);\n\n \/\/ Reads characters from the file\n input.read(array);\n System.out.println(\"Data in the stream:\");\n System.out.println(array);\n\n \/\/ Closes the reader\n input.close();\n }\n\n catch(Exception e) {\n e.getStackTrace();\n }\n }\n}\n<\/code><\/pre>\n\n\n\nOutput<\/strong><\/p>\n\n\n\nData in the stream:\nThis is a line of text inside the file.\n<\/samp><\/code><\/pre>\n\n\n\nIn the above example, we have created an input stream reader using the file input stream. The input stream reader is linked with the file input.txt<\/strong>.<\/p>\n\n\n\n FileInputStream file = new FileInputStream(\"input.txt\");\n\n InputStreamReader input = new InputStreamReader(file);\n\n<\/code><\/pre>\n\n\n\nTo read characters from the file, we have used the read()<\/code> method.<\/p>\n\n\n\n
\n\n\n\ngetEncoding() Method<\/h2>\n\n\n\n
The getEncoding()<\/code> method can be used to get the type of encoding that is used to store data in the input stream. For example,<\/p>\n\n\n\nimport java.io.InputStreamReader;\nimport java.nio.charset.Charset;\nimport java.io.FileInputStream;\n\nclass Main {\n public static void main(String[] args) {\n\n try {\n \/\/ Creates a FileInputStream\n FileInputStream file = new FileInputStream(\"input.txt\");\n\n \/\/ Creates an InputStreamReader with default encoding\n InputStreamReader input1 = new InputStreamReader(file);\n\n \/\/ Creates an InputStreamReader specifying the encoding\n InputStreamReader input2 = new InputStreamReader(file, Charset.forName(\"UTF8\"));\n\n \/\/ Returns the character encoding of the input stream\n System.out.println(\"Character encoding of input1: \" + input1.getEncoding());\n System.out.println(\"Character encoding of input2: \" + input2.getEncoding());\n\n \/\/ Closes the reader\n input1.close();\n input2.close();\n }\n\n catch(Exception e) {\n e.getStackTrace();\n }\n }\n}\n<\/code><\/pre>\n\n\n\nOutput<\/strong><\/p>\n\n\n\nThe character encoding of input1: Cp1252\nThe character encoding of input2: UTF8\n<\/samp><\/code><\/pre>\n\n\n\nIn the above example, we have created 2 input stream reader named input1<\/var> and input2<\/var>.<\/p>\n\n\n\n- input1<\/var> does not specify the character encoding. Hence the
getEncoding()<\/code> method returns the canonical name of the default character encoding.<\/li>- input2<\/var> specifies the character encoding, UTF8<\/strong>. Hence the
getEncoding()<\/code> method returns the specified character encoding.<\/li><\/ul>\n\n\n\nNote<\/strong>: We have used the\u00a0Charset.forName()<\/code>\u00a0method to specify the type of character encoding.<\/p>\n\n\n\n
\n\n\n\nclose() Method<\/h3>\n\n\n\n
To close the input stream reader, we can use the close()<\/code> method. Once the close()<\/code> method is called, we cannot use the reader to read the data.<\/p>\n\n\n\n
\n\n\n\nOther Methods of InputStreamReader<\/h2>\n\n\n\nMethod<\/th> Description<\/th><\/tr> ready()<\/code><\/td>checks if the stream is ready to be read<\/td><\/tr> mark()<\/code><\/td>mark the position in stream up to which data has been read<\/td><\/tr> reset()<\/code><\/td>returns the control to the point in the stream where the mark was set<\/td><\/tr><\/tbody><\/table><\/figure>\n","protected":false},"excerpt":{"rendered":"In this tutorial, we will learn about Java InputStreamReader and its methods with the help of examples. The InputStreamReader class of the java.io package can be used to convert data in bytes into data in characters. It extends the abstract class Reader. The InputStreamReader class works with other input streams. It is also known as a bridge between byte streams and character […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[532],"tags":[],"_links":{"self":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/1298"}],"collection":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/comments?post=1298"}],"version-history":[{"count":0,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/1298\/revisions"}],"wp:attachment":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/media?parent=1298"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/categories?post=1298"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/tags?post=1298"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}