Opens a FileOutputStream for the specified file, checking and creating the parent directory if it does not exist. - Java File Path IO

Java examples for File Path IO:Directory Create

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Description

Opens a FileOutputStream for the specified file, checking and creating the parent directory if it does not exist.

Demo Code

/**// www .  ja va2s .  c  om
 * Licensed to Jasig under one or more contributor license
 * agreements. See the NOTICE file distributed with this work
 * for additional information regarding copyright ownership.
 * Jasig licenses this file to you under the Apache License,
 * Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a
 * copy of the License at:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
//package com.java2s;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class Main {
    public static void main(String[] argv) throws Exception {
        File file = new File("Main.java");
        System.out.println(openOutputStream(file));
    }

    /**
     * Opens a {@link FileOutputStream} for the specified file, checking and
     * creating the parent directory if it does not exist.
     * <p>
     * At the end of the method either the stream will be successfully opened,
     * or an exception will have been thrown.
     * <p>
     * The parent directory will be created if it does not exist.
     * The file will be created if it does not exist.
     * An exception is thrown if the file object exists but is a directory.
     * An exception is thrown if the file exists but cannot be written to.
     * An exception is thrown if the parent directory cannot be created.
     * 
     * @param file  the file to open for output, must not be <code>null</code>
     * @return a new {@link FileOutputStream} for the specified file
     * @throws IOException if the file object is a directory
     * @throws IOException if the file cannot be written to
     * @throws IOException if a parent directory needs creating but that fails
     * @since Commons IO 1.3
     */
    static FileOutputStream openOutputStream(File file) throws IOException {
        if (file.exists()) {
            if (file.isDirectory()) {
                throw new IOException("File '" + file
                        + "' exists but is a directory");
            }
            if (file.canWrite() == false) {
                throw new IOException("File '" + file
                        + "' cannot be written to");
            }
        } else {
            File parent = file.getParentFile();
            if (parent != null && parent.exists() == false) {
                if (parent.mkdirs() == false) {
                    throw new IOException("File '" + file
                            + "' could not be created");
                }
            }
        }
        return new FileOutputStream(file);
    }
}

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