从java中的属性文件中读取正则表达式

Question

I have problem reading values like (\\+?\\s*[0-9]+\\s*)+ from properties file in java, because the value , what I get with getProperty() method is (+?s*[0-9]+s*)+ .

Escaping of values in properties file is not an option yet.

Any ideas?

Answer 1

I think this class could be solution for the backslash problem in properties file.

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.HashMap;

public class ProperProps {

    HashMap<String, String> Values = new HashMap<String, String>();

    public ProperProps() {
    };

    public ProperProps(String filePath) throws java.io.IOException {
        load(filePath);
    }

    public void load(String filePath) throws IOException {
        BufferedReader reader = new BufferedReader(new FileReader(filePath));
        String line;
        while ((line = reader.readLine()) != null) {
            if (line.trim().length() == 0 || line.startsWith("#"))
                continue;

            String key = line.replaceFirst("([^=]+)=(.*)", "$1");
            String val = line.replaceFirst("([^=]+)=(.*)", "$2");
            Values.put(key, val);

        }
        reader.close();
    }


    public String getProperty(String key) {
        return Values.get(key);
    }


    public void printAll() {
        for (String key : Values.keySet())
            System.out.println(key +"=" + Values.get(key));
    }


    public static void main(String [] aa) throws IOException {
        // example & test 
        String ptp_fil_nam = "my.prop";
        ProperProps pp = new ProperProps(ptp_fil_nam);
        pp.printAll();
    }
}

Answer 2

I am pretty late to answer this question, but maybe this could help others that end up here.

Newer versions of Java (not sure which, I am using 8) support escaping of values by using \\\\ to represent the normal \\ we are used to.

For example, in your case, (\\\\+?\\\\s*[0-9]+\\\\s*)+ is what you are looking for.

Answer 3

Just read using a classical BufferedReader instead:

final URL url = MyClass.class.getResource("/path/to/propertyfile");
// check if URL is null;

String line;

try (
    final InputStream in = url.openStream();
    final InputStreamReader r 
        = new InputStreamReader(in, StandardCharsets.UTF_8);
    final BufferedReader reader = new BufferedReader(r);
) {
    while ((line = reader.readLine()) != null)
        // process line
}

Adapt to Java 6 if necessary...