java使用stringbuilder读取属性和xml文件

Question

I need to read a set of xml and property files and parse the data. Currently I am using inputstream ans string builder to do this. But this does not create the file in the same way as input file is. I donot want to remove the white spaces and new lines. How do i achieve this.

is = test.getInputStream();
br = new BufferedReader(new InputStreamReader(is));
String line5;
StringBuilder sb5 = new StringBuilder();
while ((line5 = br.readLine()) != null) {
    sb5.append(line5);
} 
String s = sb5.toString();

My output is:

#test 123 #test2 345

Expected output is:

#test
123
#test2
345

Any thoughts ? Thanks

Answer 1

br.readLine() consumes the line breaks, you need to add them to your StringBuilder after appending the line.

is = test.getInputStream();
br = new BufferedReader(new InputStreamReader(is));
String line5;
StringBuilder sb5 = new StringBuilder();
while ((line5 = br.readLine()) != null) {
    sb5.append(line5);
    sb5.append("\n");
}

If you want an extremely simple solution for reading a file to a String, Apache Commons-IO has a method for performing such a task ( org.apache.commons.io.FileUtils ).

FileUtils.readFileToString(File file, String encoding);

Answer 2

readLine() method doesn't add the EOL character (\\n). So while appending the string to the builder, you need to add the EOL char, like sb5.append(line5+"\\n");

Answer 3

The various readLine methods discard the newline from the input.

From the BufferedReader docs :

Returns: A String containing the contents of the line, not including any line-termination characters, or null if the end of the stream has been reached

A solution may be as simple as adding back a newline to your StringBuilder for every readLine : sb5.append(line5 + "\\n"); .

A better alternative is to read into an intermediate buffer first, using the read method, supplying your own char[] . You can still use StringBuilder.append , and get a String will match the file contents.