org.snaker.engine.helper.StreamHelper Maven / Gradle / Ivy
/* Copyright 2013-2014 the original author or authors.
*
* Licensed 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 org.snaker.engine.helper;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;
import java.net.URL;
import org.snaker.engine.SnakerException;
/**
* 流数据帮助类
* @author yuqs
* @version 1.0
*/
public class StreamHelper {
public static final int DEFAULT_CHUNK_SIZE = 1024;
public static final int BUFFERSIZE = 4096;
/**
* 根据文件名称resource打开输入流，并返回
* @param resource
* @return
*/
public static InputStream openStream(String resource) {
ClassLoader classLoader = Thread.currentThread()
.getContextClassLoader();
InputStream stream = classLoader.getResourceAsStream(resource);
if (stream == null) {
stream = StreamHelper.class.getClassLoader().getResourceAsStream(resource);
}
return stream;
}
public static InputStream getStreamFromString(String text) {
try {
byte[] bytes = text.getBytes("UTF-8");
return new ByteArrayInputStream(bytes);
} catch (Exception e) {
throw new AssertionError(e);
}
}
public static InputStream getStreamFromFile(File file) {
InputStream stream = null;
try {
if (!file.exists()) {
throw new SnakerException("file " + file + " doesn't exist");
}
if (file.isDirectory()) {
throw new SnakerException("file " + file + " is a directory");
}
stream = new FileInputStream(file);
} catch (Exception e) {
throw new SnakerException("couldn't access file " + file + ": "
+ e.getMessage(), e);
}
return stream;
}
public static InputStream getStreamFromClasspath(String resourceName) {
ClassLoader classLoader = Thread.currentThread()
.getContextClassLoader();
InputStream stream = classLoader.getResourceAsStream(resourceName);
if (stream == null) {
stream = StreamHelper.class.getClassLoader().getResourceAsStream(
resourceName);
}
if (stream == null) {
throw new SnakerException("resource " + resourceName
+ " does not exist");
}
return stream;
}
public static InputStream getStreamFromUrl(URL url) {
InputStream stream = null;
try {
stream = url.openStream();
} catch (IOException e) {
throw new SnakerException("couldn't open URL stream", e);
}
return stream;
}
public static byte[] readBytes(InputStream in) throws IOException {
ByteArrayOutputStream out = new ByteArrayOutputStream();
transfer(in, out);
return out.toByteArray();
}
public static long transfer(InputStream in, OutputStream out)
throws IOException {
long total = 0;
byte[] buffer = new byte[BUFFERSIZE];
for (int count; (count = in.read(buffer)) != -1;) {
out.write(buffer, 0, count);
total += count;
}
return total;
}
/**
* input->output字节流copy
* @param inputStream
* @param outputStream
* @return
* @throws IOException
*/
public static long copy(InputStream inputStream, OutputStream outputStream) throws IOException {
return copy( inputStream, outputStream, DEFAULT_CHUNK_SIZE );
}
/**
* input->output字节流copy
* @param inputStream
* @param outputStream
* @param bufferSize
* @return
* @throws IOException
*/
public static long copy(InputStream inputStream, OutputStream outputStream, int bufferSize) throws IOException {
byte[] buffer = new byte[bufferSize];
long count = 0;
int n;
while ( -1 != ( n = inputStream.read( buffer ) ) ) {
outputStream.write( buffer, 0, n );
count += n;
}
return count;
}
public static long copy(Reader reader, Writer writer) throws IOException {
return copy( reader, writer, DEFAULT_CHUNK_SIZE );
}
public static long copy(Reader reader, Writer writer, int bufferSize) throws IOException {
char[] buffer = new char[bufferSize];
long count = 0;
int n;
while ( -1 != ( n = reader.read( buffer ) ) ) {
writer.write( buffer, 0, n );
count += n;
}
return count;
}
}