使用netty实现文件上传服务器

jiezi

5 年前

代码实现根据官网提供的 example https://github.com/netty/nett…
以及 netty 官网的 api 文档 https://netty.io/4.1/api/inde…
项目地址 https://github.com/1433365571…

1 编写 server 启动类

package server;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.ssl.SslContext;
import io.netty.handler.ssl.SslContextBuilder;
import io.netty.handler.ssl.util.SelfSignedCertificate;

public final class HttpUploadServer {static final boolean SSL = System.getProperty("ssl") != null;

    static final int PORT = Integer.parseInt(System.getProperty("port", SSL ? "8443" : "8080"));

    public static void main(String[] args) throws Exception {
        // Configure SSL.
        final SslContext sslCtx;
        if (SSL) {SelfSignedCertificate ssc = new SelfSignedCertificate();
            sslCtx = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey()).build();} else {sslCtx = null;}

        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {ServerBootstrap b = new ServerBootstrap();

            b.group(bossGroup, workerGroup);

            b.channel(NioServerSocketChannel.class);

            b.handler(new LoggingHandler(LogLevel.INFO));

            b.childHandler(new HttpUploadServerInitializer(sslCtx));

            Channel ch = b.bind(PORT).sync().channel();

            System.err.println("Open your web browser and navigate to" +
                    (SSL ? "https" : "http") + "://127.0.0.1:" + PORT + '/');

            ch.closeFuture().sync();

        } finally {bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();}
    }
}

2 绑定 handler

/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project 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 server;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpContentCompressor;
import io.netty.handler.codec.http.HttpRequestDecoder;
import io.netty.handler.codec.http.HttpResponseEncoder;
import io.netty.handler.ssl.SslContext;

public class HttpUploadServerInitializer extends ChannelInitializer<SocketChannel> {

    private final SslContext sslCtx;

    public HttpUploadServerInitializer(SslContext sslCtx) {this.sslCtx = sslCtx;}

    @Override
    public void initChannel(SocketChannel ch) {ChannelPipeline pipeline = ch.pipeline();

        if (sslCtx != null) {pipeline.addLast(sslCtx.newHandler(ch.alloc()));

        }

        pipeline.addLast(new HttpRequestDecoder());

        pipeline.addLast(new HttpResponseEncoder());

        // Remove the following line if you don't want automatic content compression.
        pipeline.addLast(new HttpContentCompressor());

//        pipeline.addLast("http-aggregator",
//                new HttpObjectAggregator(65536));// 目的是将多个消息转换为单一的 request 或者 response 对象

        pipeline.addLast(new HttpUploadServerHandler());
    }


}

3 上传处理的 handler


package server;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http.multipart.*;
import io.netty.util.CharsetUtil;

import java.io.File;
import java.io.IOException;
import java.net.URI;

public class HttpUploadServerHandler extends SimpleChannelInboundHandler<HttpObject> {

    private HttpRequest request;

    private static final String uploadUrl = "/up";

    private static final String fromFileUrl = "/post_multipart";

    private static final HttpDataFactory factory =
            new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE); // Disk if size exceed

    private HttpPostRequestDecoder decoder;

    static {
        DiskFileUpload.deleteOnExitTemporaryFile = true; // should delete file
        // on exit (in normal
        // exit)
        DiskFileUpload.baseDirectory = null; // system temp directory
        DiskAttribute.deleteOnExitTemporaryFile = true; // should delete file on
        // exit (in normal exit)
        DiskAttribute.baseDirectory = null; // system temp directory
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) {if (decoder != null) {decoder.cleanFiles();
        }
    }

    protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception {if (msg instanceof HttpRequest) {this.request = (HttpRequest) msg;

            URI uri = new URI(request.uri());

            System.out.println(uri);

            urlRoute(ctx, uri.getPath());

        }

        if (decoder != null) {if (msg instanceof HttpContent) {

                // 接收一个新的请求体
                decoder.offer((HttpContent) msg);
                // 将内存中的数据序列化本地
                readHttpDataChunkByChunk();}

            if (msg instanceof LastHttpContent) {System.out.println("LastHttpContent");

                reset();

                writeResponse(ctx, "<h1> 上传成功 </h1>");

            }

        }


    }

    // url 路由
    private void urlRoute(ChannelHandlerContext ctx, String uri) {StringBuilder urlResponse = new StringBuilder();

        // 访问文件上传页面
        if (uri.startsWith(uploadUrl)) {urlResponse.append(getUploadResponse());

        } else if (uri.startsWith(fromFileUrl)) {decoder = new HttpPostRequestDecoder(factory, request);

            return;

        } else {urlResponse.append(getHomeResponse());

        }

        writeResponse(ctx, urlResponse.toString());

    }

    private void writeResponse(ChannelHandlerContext ctx, String context) {ByteBuf buf = Unpooled.copiedBuffer(context, CharsetUtil.UTF_8);

        FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, buf);

        response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html;charset=utf-8");

        ctx.channel().writeAndFlush(response);

    }

    private String getHomeResponse() {return "<h1> welcome home </h1>";}

    private String getUploadResponse() {

        return "<!DOCTYPE html>\n" +
                "<html lang=\"en\">\n" +
                "<head>\n" +
                "<meta charset=\"UTF-8\">\n" +
                "<title>Title</title>\n" +
                "</head>\n" +
                "<body>\n" +
                "\n" +
                "<form action=\"http://127.0.0.1:8080/post_multipart\"enctype=\"multipart/form-data\"method=\"POST\">\n" +
                "\n" +
                "\n" +
                "<input type=\"file\"name=" +
                "" +"" +
                "\"YOU_KEY\">\n" +
                "\n" +
                "<input type=\"submit\"name=\"send\">\n" +
                "\n" +
                "</form>\n" +
                "\n" +
                "</body>\n" +
                "</html>";

    }


    private void readHttpDataChunkByChunk() throws IOException {while (decoder.hasNext()) {InterfaceHttpData data = decoder.next();

            if (data != null) {if (data.getHttpDataType() == InterfaceHttpData.HttpDataType.FileUpload) {FileUpload fileUpload = (FileUpload) data;

                    if (fileUpload.isCompleted()) {fileUpload.isInMemory();// tells if the file is in Memory
                        // or on File
                        fileUpload.renameTo(new File(PathUtil.getFileBasePath() + fileUpload.getFilename())); // enable to move into another
                        // File dest
                        decoder.removeHttpDataFromClean(fileUpload); //remove

                    }


                }

            }
        }

    }

    private void reset() {

        request = null;

        // destroy the decoder to release all resources
        decoder.destroy();

        decoder = null;

    }

}

4 环境文件

package server;

import java.io.File;

public class PathUtil {private static final ClassLoader classLoader = PathUtil.class.getClassLoader();

    public static String getFileBasePath() {String os = System.getProperty("os.name");
        String basePath;
        if (os.toLowerCase().startsWith("win")) {basePath = "D:/warehouse/";} else {basePath = "/root/upload_source";}
        basePath = basePath.replace("/", File.separator);
        return basePath;
    }

    public static String getSourcePath(String name) {return classLoader.getResource(name).getPath();}
}

5 pom 文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>nettyHttpUploadServer</groupId>
    <artifactId>http.upload</artifactId>
    <version>1.0-SNAPSHOT</version>


    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>

        <!-- https://mvnrepository.com/artifact/io.netty/netty-all -->
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.10.Final</version>
        </dependency>

    </dependencies>

    <!--    <build>-->
    <!--        <plugins>-->
    <!--            <plugin>-->
    <!--                <groupId>org.apache.maven.plugins</groupId>-->
    <!--                <artifactId>maven-jar-plugin</artifactId>-->

    <!--                <configuration>-->
    <!--                    <archive>-->
    <!--                        <manifest>-->
    <!--                            <addClasspath>true</addClasspath>-->
    <!--                            <mainClass>server.HttpUploadServer</mainClass>-->
    <!--                        </manifest>-->
    <!--                    </archive>-->
    <!--                </configuration>-->

    <!--            </plugin>-->
    <!--        </plugins>-->
    <!--    </build>-->
    <build>

        <plugins>
            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <version>3.0.0</version>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>server.HttpUploadServer</mainClass>
                        </manifest>
                    </archive>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                </configuration>
                <executions>
                    <execution>
                        <id>make-assembly</id>
                        <phase>package</phase>
                        <goals>
                            <goal>single</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>server.HttpUploadServer</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
            <plugin>
                <groupId>com.jolira</groupId>
                <artifactId>onejar-maven-plugin</artifactId>
                <version>1.4.4</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>one-jar</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>

    </build>


</project>

6 代码说明

ChannelHandlerContext 控制数据处理管道 ChannelPipeline 执行流程
HttpObject 消息处理的接口
HttpRequest 封装 http 请求头请求协议等
DefaultFullHttpResponse 构造 http 响应
httpcontext netty 会将请求体分组处理，获得完整的请求体可以请将 HttpObjectAggregator 放在 ChannelPipeline 中的
HttpObjectDecoder 之后此文章解释较详细。
LastHttpContent 标识 Http 请求结束
HttpDataFactory 上传文件的处理方式
HttpPostRequestDecoder post 请求体的解析类

7 访问 http://127.0.0.1:8080/up 上传文件

使用 netty 实现文件上传服务器