在实际开发过程中，我们经常需要将某台服务器的文件自动上传到另外一台服务器。这时我们就需要一个文件自动上传工具，Apache Camel就很好的实现这个功能。

1.创建一个Spring Boot项目

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选择依赖jar包：添加camel及web的依赖

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确定创建项目信息

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2.在POM文件中添加其他依赖

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.liwei</groupId>
    <artifactId>camel-file</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>camel-file</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-spring-boot-starter</artifactId>
            <version>2.23.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>4.4.9</version>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-http4</artifactId>
            <version>2.23.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
            <version>4.5.5</version>
        </dependency>
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

3.application.yml配置

file.from: file:E:/from/?recursive=true  #源文件地址,recursive参数是递归from文件夹，具体参数见http://camel.apache.org/file2
file.to: E:/to/ #需要写入的目录
file.upload: http4://127.0.0.1:8080/upload #上传文件的接口

4.设置文件夹监听

设置文件夹监听，当文件夹有新增文件时，会自动触发上传。from为需要上传的文件夹目录，本实例为file:E:/from/?recursive=true，recursive参数的意思是：查找子目录的文件，若为false，则只上传当前目录的文件，如有其他要求，可查询http://camel.apache.org/file2

package com.liwei.camelfile;
import org.apache.camel.Exchange;
import org.apache.camel.builder.RouteBuilder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class FileUploaderRoute extends RouteBuilder {
    @Autowired
    private CamelToolProcess camelToolProcess ;
    @Override
    public void configure() {
        from("{{file.from}}")
                .process(camelToolProcess )
                .setHeader(Exchange.HTTP_METHOD, constant("POST"))
                .setHeader(Exchange.CONTENT_TYPE, constant("multipart/form-data"))
                .to("{{file.upload}}");
    }
}

5.文件处理CamelToolProcess

//构造HTTP请求文件上传格式
package com.liwei.camelfile;
import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.apache.http.entity.mime.HttpMultipartMode;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
import org.springframework.stereotype.Component;
import java.io.File;
import static org.apache.http.entity.ContentType.MULTIPART_FORM_DATA;

@Component
public class CamelToolProcess implements Processor {
    @Override
    public void process(Exchange exchange) {

        MultipartEntityBuilder multipartEntityBuilder =
                MultipartEntityBuilder.create();
        multipartEntityBuilder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);

        String filename = (String)
                exchange.getIn().getHeader(Exchange.FILE_NAME);
        File file = exchange.getIn().getBody(File.class);
        multipartEntityBuilder.addPart("file",
                new FileBody(file, MULTIPART_FORM_DATA, filename));

        exchange.getIn().setBody(multipartEntityBuilder.build());
    }
}

6.上传文件接口

package com.liwei.camelfile.control;
import org.apache.commons.io.FileUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;
import java.io.File;
import java.io.IOException;

@RestController
public class FileController {
    @Value("${file.to}")
    private String to;

    @PostMapping("/upload")
    @ResponseBody
    public void upload(@RequestParam("file") MultipartFile file) throws IOException {
        FileUtils.writeByteArrayToFile(new File(to + file.getOriginalFilename()), file.getBytes());
    }
}

7.测试

上传完成后会自动创建一个.camel文件，将上传成功的文件写入.camel目录中

image-20210314225336986.png

目标服务器的目录

image-20210314225508278.png