3、Netty HTTP协议开发
关于HTTP的介绍，参见HTTP协议介绍
FileServer应用开发
Netty HTTP服务端开发：
public class HttpFileServer {
private static final String DEFAULT_URL = "/src/main/java/com/kim/";
private static String ip = "10.200.88.159";
static {
try {
//获取本地IP
ip = InetAddress.getLocalHost().getHostAddress();
} catch (UnknownHostException e) {
e.printStackTrace();
}
}
public void run(final int port, final String url) throws Exception {
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer() {
@Override
protected void initChannel(SocketChannel ch)
throws Exception {
//添加请求消息解码器，对HTTP 请求解码
ch.pipeline().addLast("http-decoder",
new HttpRequestDecoder());
//添加HttpObjectAggregator解码器，将多个消息转为单一的FullHttpRequest或者FullHttpResponse
//因为HTTP解码器会在每个HTTP消息中生成多个消息对象：
/*
1、HttpRequest/HttpResponse
2、HttpContent
3、LastHttpContent
*/
ch.pipeline().addLast("http-aggregator",
new HttpObjectAggregator(65536));
//添加响应编码器
ch.pipeline().addLast("http-encoder",
new HttpResponseEncoder());
//ChunkedWriteHandler支持异步传输大的码流（例如大的文件传输），不占用过多内存，防止内存溢出
ch.pipeline().addLast("http-chunked",
new ChunkedWriteHandler());
//添加文件服务器业务处理器
ch.pipeline().addLast("fileServerHandler",
new HttpFileServerHandler(url));
}
});
ChannelFuture future = b.bind(ip, port).sync();
System.out.println("HTTP文件目录服务器启动，网址是 : " + "http://" + ip + ":"
+ port + url);
future.channel().closeFuture().sync();
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
public static void main(String[] args) throws Exception {
int port = 8080;
if (args.length > 0) {
try {
port = Integer.parseInt(args[0]);
} catch (NumberFormatException e) {
e.printStackTrace();
}
}
String url = DEFAULT_URL;
if (args.length > 1) {
url = args[1];
}
new HttpFileServer().run(port, url);
}
} public class HttpFileServerHandler extends
SimpleChannelInboundHandler {
private final String url;
public HttpFileServerHandler(String url) {
this.url = url;
}
@Override
public void channelRead0(ChannelHandlerContext ctx,
FullHttpRequest request) throws Exception {
//解码失败，返回400，客户端请求错误
if (!request.decoderResult().isSuccess()) {
sendError(ctx, BAD_REQUEST);
return;
}
//只能接收GET请求
if (request.method() != GET) {
sendError(ctx, METHOD_NOT_ALLOWED);
return;
}
//获取和构造URI，返回资源定位符
final String uri = request.uri();
final String path = sanitizeUri(uri);
//如果路径不合法，返回403
if (path == null) {
sendError(ctx, FORBIDDEN);
return;
}
//如果文件不存在或者是隐藏文件，返回404
File file = new File(path);
if (file.isHidden() || !file.exists()) {
sendError(ctx, NOT_FOUND);
return;
}
//如果是目录，发送目录的链接给浏览器
if (file.isDirectory()) {
if (uri.endsWith("/")) {
sendListing(ctx, file);
} else {
sendRedirect(ctx, uri + '/');
}
return;
}
//如果不是个文件，返回403
if (!file.isFile()) {
sendError(ctx, FORBIDDEN);
return;
}
RandomAccessFile randomAccessFile = null;
try {
//使用随机文件读写类以只读的方式打开文件
randomAccessFile = new RandomAccessFile(file, "r");// 以只读的方式打开文件
} catch (FileNotFoundException fnfe) {
sendError(ctx, NOT_FOUND);
return;
}
//获取文件的长度
long fileLength = randomAccessFile.length();
//构造成功的http应答消息
HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);
//消息头中设置content length和 content type
setContentLength(response, fileLength);
setContentTypeHeader(response, file);
//判断是否是KeepAlive
if (isKeepAlive(request)) {
//如果是，在应答消息头中设置connection为keepalive
response.headers().set(CONNECTION, HttpHeaderValues.KEEP_ALIVE);
}
//将响应头写入channel，发送响应消息
ctx.write(response);
ChannelFuture sendFileFuture;
//通过Netty的ChunkedFile对象直接将文件写入到发送缓冲区
sendFileFuture = ctx.write(new ChunkedFile(randomAccessFile, 0,
fileLength, 8192), ctx.newProgressivePromise());
//为sendFileFuture添加GenericFutureListener
sendFileFuture.addListener(new ChannelProgressiveFutureListener() {
@Override
public void operationProgressed(ChannelProgressiveFuture future,
long progress, long total) {
if (total < 0) { // total unknown
System.err.println("Transfer progress: " + progress);
} else {
System.err.println("Transfer progress: " + progress + " / "
+ total);
}
}
@Override
public void operationComplete(ChannelProgressiveFuture future)
throws Exception {
//如果发送完成，打印Transfer complete.
System.out.println("Transfer complete.");
}
});
//如果使用chunked编码，最后需要发送一个编码结束的空消息体，将LastHttpContent.EMPTY_LAST_CONTENT发送到缓冲区中，标识所有的消息体已经发送完成
//同时调用flush方法将之前在发送缓冲区的消息刷新到SocketChannel中发送给对方
ChannelFuture lastContentFuture = ctx
.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
//如果是非keepalive的，最后一包消息发送完之后，服务端要主动关闭连接
if (!isKeepAlive(request)) {
lastContentFuture.addListener(ChannelFutureListener.CLOSE);
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
cause.printStackTrace();
if (ctx.channel().isActive()) {
sendError(ctx, INTERNAL_SERVER_ERROR);
}
}
private static final Pattern INSECURE_URI = Pattern.compile(".*[<>&\"].*");
private String sanitizeUri(String uri) {
try {
//对uri解码
uri = URLDecoder.decode(uri, "UTF-8");
} catch (UnsupportedEncodingException e) {
try {
uri = URLDecoder.decode(uri, "ISO-8859-1");
} catch (UnsupportedEncodingException e1) {
throw new Error();
}
}
//解码成功，对uri进行合法性判断
if (!uri.startsWith(url)) {
return null;
}
if (!uri.startsWith("/")) {
return null;
}
//将分隔符替换为操作系统文件路径分隔符
uri = uri.replace('/', File.separatorChar);
if (uri.contains(File.separator + '.')
|| uri.contains('.' + File.separator) || uri.startsWith(".")
|| uri.endsWith(".") || INSECURE_URI.matcher(uri).matches()) {
return null;
}
//对文件路径拼接，当前运行程序所在的工程目录+uri的绝对路径
return System.getProperty("user.dir") + File.separator + uri;
}
private static final Pattern ALLOWED_FILE_NAME = Pattern
.compile("[A-Za-z0-9][-_A-Za-z0-9\\.]*");
private static void sendListing(ChannelHandlerContext ctx, File dir) {
FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, OK);
response.headers().set(CONTENT_TYPE, "text/html; charset=UTF-8");
StringBuilder buf = new StringBuilder();
String dirPath = dir.getPath();
buf.append("\r\n");
buf.append("");
buf.append(dirPath);
buf.append(" 目录：");
buf.append(" \r\n");
buf.append("");
buf.append(dirPath).append(" 目录：");
buf.append("
\r\n");
buf.append("");
buf.append("- 链接：..
\r\n");
for (File f : dir.listFiles()) {
if (f.isHidden() || !f.canRead()) {
continue;
}
String name = f.getName();
if (!ALLOWED_FILE_NAME.matcher(name).matches()) {
continue;
}
buf.append("- 链接：");
buf.append(name);
buf.append("
\r\n");
}
buf.append("
\r\n");
//分配对应消息的缓冲对象
ByteBuf buffer = Unpooled.copiedBuffer(buf, CharsetUtil.UTF_8);
//将缓冲区中的响应消息存放到HTTP的应答消息中
response.content().writeBytes(buffer);
//释放缓冲区
buffer.release();
//将响应消息发送到缓冲区，并刷新到SocketChannel
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
private static void sendRedirect(ChannelHandlerContext ctx, String newUri) {
FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, FOUND);
response.headers().set(LOCATION, newUri);
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
private static void sendError(ChannelHandlerContext ctx,
HttpResponseStatus status) {
FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1,
status, Unpooled.copiedBuffer("Failure: " + status.toString()
+ "\r\n", CharsetUtil.UTF_8));
response.headers().set(CONTENT_TYPE, "text/plain; charset=UTF-8");
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
private static void setContentTypeHeader(HttpResponse response, File file) {
MimetypesFileTypeMap mimeTypesMap = new MimetypesFileTypeMap();
response.headers().set(CONTENT_TYPE,
mimeTypesMap.getContentType(file.getPath()));
}
} 运行结果：
Netty HTTP+XML协议栈开发
HttpXmlClient
Bootstrap b = new Bootstrap();
b.group(group).channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.handler(new ChannelInitializer() {
@Override
public void initChannel(SocketChannel ch)
throws Exception {
//负责将二进制码流解码成HTTP应答消息
ch.pipeline().addLast("http-decoder",
new HttpResponseDecoder());
//将一个HTTP请求的多个部分合并成一个完成的HTTP消息
ch.pipeline().addLast("http-aggregator",
new HttpObjectAggregator(65536));
// XML响应解码器，解码服务端的响应消息
ch.pipeline().addLast(
"xml-decoder",
new HttpXmlResponseDecoder(Order.class,
true));
//编码的时候按照从后往前的顺序调度进行
ch.pipeline().addLast("http-encoder",
new HttpRequestEncoder());
// XML请求编码器，将客户端消息编码
ch.pipeline().addLast("xml-encoder",
new HttpXmlRequestEncoder());
//添加业务逻辑编排类
ch.pipeline().addLast("xmlClientHandler",
new HttpXmlClientHandle());
}
}); 
客户端处理器HttpXmlClientHandle：
public class HttpXmlClientHandle extends
SimpleChannelInboundHandler {
@Override
public void channelActive(ChannelHandlerContext ctx) {
//构造HttpXmlRequest对象
HttpXmlRequest request = new HttpXmlRequest(null,
OrderFactory.create(123));
//发送HttpXmlRequest
ctx.writeAndFlush(request);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
@Override
protected void channelRead0(ChannelHandlerContext ctx,
HttpXmlResponse msg) throws Exception {
//接收已经自动解码后的HttpXmlResponse对象
System.out.println("The client receive response of http header is : "
+ msg.getHttpResponse().headers().names());
System.out.println("The client receive response of http body is : "
+ msg.getResult());
}
} HttpXmlServer
HttpXmlServerHandler
1、接收客户端的信息
2、处理业务逻辑
3、发送响应给客户端
public class HttpXmlServerHandler extends
SimpleChannelInboundHandler {
@Override
public void channelRead0(final ChannelHandlerContext ctx,
HttpXmlRequest xmlRequest) throws Exception {
//获取到已经解码的HttpXmlRequest
HttpRequest request = xmlRequest.getRequest();
//获取请求消息对象，将其打印出来
Order order = (Order) xmlRequest.getBody();
System.out.println("Http server receive request : " + order);
//对Order请求消息进行业务逻辑编排
dobusiness(order);
//发送应答消息，发送成功后关闭链路
ChannelFuture future = ctx.writeAndFlush(new HttpXmlResponse(null,
order));
if (!isKeepAlive(request)) {
future.addListener(new GenericFutureListener>() {
@Override
public void operationComplete(Future future) throws Exception {
ctx.close();
}
});
}
}
private void dobusiness(Order order) {
order.getCustomer().setFirstName("狄");
order.getCustomer().setLastName("仁杰");
List midNames = new ArrayList();
midNames.add("李元芳");
order.getCustomer().setMiddleNames(midNames);
Address address = order.getBillTo();
address.setCity("洛阳");
address.setCountry("大唐");
address.setState("河南道");
address.setPostCode("123456");
order.setBillTo(address);
order.setShipTo(address);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
cause.printStackTrace();
//在发生异常并且链路没有关闭的情况下，构造内部异常消息发送给客户端，发送完成后关闭链路
if (ctx.channel().isActive()) {
sendError(ctx, INTERNAL_SERVER_ERROR);
}
}
private static void sendError(ChannelHandlerContext ctx,
HttpResponseStatus status) {
FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1,
status, Unpooled.copiedBuffer("失败: " + status.toString()
+ "\r\n", CharsetUtil.UTF_8));
response.headers().set(CONTENT_TYPE, "text/plain; charset=UTF-8");
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
} 遗留的问题：
客户端处理器中的channelRead0方法，始终没能运行到，无法输出服务端的响应消息。