Spring.Resource

 

 

 

ByteArrayResource：通过byte 数组构建Resource

public class ByteArrayResource extends AbstractResource {

	private final byte[] byteArray;

	private final String description;

	/**
	 * This implementation returns a ByteArrayInputStream for the
	 * underlying byte array.
	 * @see java.io.ByteArrayInputStream
	 */
	public InputStream getInputStream() throws IOException {
		return new ByteArrayInputStream(this.byteArray);
	}

}

 FileSystemResource：文件资源，可读写

public class FileSystemResource extends AbstractResource implements WritableResource {

	private final File file;

	private final String path;

	/**
	 * This implementation opens a FileInputStream for the underlying file.
	 * @see java.io.FileInputStream
	 */
	public InputStream getInputStream() throws IOException {
		return new FileInputStream(this.file);
	}

	/**
	 * This implementation opens a FileOutputStream for the underlying file.
         * WritableResouce接口方法
	 * @see java.io.FileOutputStream
	 */
	public OutputStream getOutputStream() throws IOException {
		return new FileOutputStream(this.file);
	}
	/**
	 * Create a new FileSystemResource from a file path.
	 * <p>Note: When building relative resources via {@link #createRelative},
	 * it makes a difference whether the specified resource base path here
	 * ends with a slash or not. In the case of "C:/dir1/", relative paths
	 * will be built underneath that root: e.g. relative path "dir2" ->
	 * "C:/dir1/dir2". In the case of "C:/dir1", relative paths will apply
	 * at the same directory level: relative path "dir2" -> "C:/dir2".
	 * @param path a file path
	 */
	public FileSystemResource(String path) {
		Assert.notNull(path, "Path must not be null");
		this.file = new File(path);
		this.path = StringUtils.cleanPath(path);//路径处理：如前缀，..等
	}
}

 ClassPathResource:

 通过给定的classLoader或者class加载资源文件

public class ClassPathResource extends AbstractFileResolvingResource {

	private final String path;

	private ClassLoader classLoader;

	private Class<?> clazz;

public ClassPathResource(String path, ClassLoader classLoader) {
		Assert.notNull(path, "Path must not be null");
		String pathToUse = StringUtils.cleanPath(path);
		if (pathToUse.startsWith("/")) {
			pathToUse = pathToUse.substring(1);
		}
		this.path = pathToUse;
               //classLoader为空，则初始化当前线程的classLoader Thread.currentThread().getContextClassLoader();
		this.classLoader = (classLoader != null ? classLoader : ClassUtils.getDefaultClassLoader());
	}
}

    资源文件方式：

    

	/**
	 * This implementation opens an InputStream for the given class path resource.
	 * @see java.lang.ClassLoader#getResourceAsStream(String)
	 * @see java.lang.Class#getResourceAsStream(String)
	 */
	public InputStream getInputStream() throws IOException {
		InputStream is;
		if (this.clazz != null) {
			is = this.clazz.getResourceAsStream(this.path);
		}
		else {
			is = this.classLoader.getResourceAsStream(this.path);
		}
		if (is == null) {
			throw new FileNotFoundException(
					getDescription() + " cannot be opened because it does not exist");
		}
		return is;
	}