java代码在阿里云函数计算中的应用

分享一个阿里云函数计算的java应用。

服务的功能是获取OSS中PPT模板，加载OSS中图片文件，合成PPT导出文件后，把文件回传到OSS方便下载的应用。

移植到函数计算的目的是OSS文件都在阿里云中，服务器迁移到了腾讯云，让代码更靠近数据，方便计算。

MAVEN配置里的build这块比较重要，把关联jar都会打包到一个jar中，这样才能上传到函数计算服务中。

<build>
        <plugins>
            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <version>3.1.0</version>
                <configuration>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                    <appendAssemblyId>false</appendAssemblyId> <!-- this is used for not append id to the jar name -->
                </configuration>
                <executions>
                    <execution>
                        <id>make-assembly</id> <!-- this is used for inheritance merges -->
                        <phase>package</phase> <!-- bind to the packaging phase -->
                        <goals>
                            <goal>single</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>

package example;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLDecoder;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.FileUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.poi.xslf.usermodel.XMLSlideShow;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.aliyun.fc.runtime.Context;
import com.aliyun.fc.runtime.FunctionComputeLogger;
import com.aliyun.fc.runtime.HttpRequestHandler;

public class App2 implements HttpRequestHandler {

    /**
     * 模板默认的可变化的起始页，从这页开始插入生成的PPT
     */
    public static final String FIELD_FLAG = "#";

    private static final Map<String, String> POINT_MAP = BizConstants.getInnerAttributeMap();

    private FunctionComputeLogger logger;

    private String getV(HttpServletRequest request, String key) {
        return (String)request.getAttribute(key);
    }

    /**
     * 获取body中的内容
     * 
     * @param request
     * @return
     */
    private String getBody(HttpServletRequest request) {
        BufferedReader br;
        try {
            br = request.getReader();
            String str, wholeStr = "";
            while ((str = br.readLine()) != null) {
                wholeStr += str;
            }
            wholeStr = URLDecoder.decode(wholeStr, "utf-8");
            return wholeStr;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    public void handleRequest(HttpServletRequest request, HttpServletResponse response, Context context)
        throws IOException, ServletException {

        logger = context.getLogger();

        
        /**
         * 获取客户端提交的BODY部分数据
         */
        String body = getBody(request);

        logger.info("body=====>" + body);

        /**
         * 解析JSON对象
         */
        JSONObject obj = JSON.parseObject(body);

        Integer pageSize = obj.getInteger("pageSize");
        String pptUrl = obj.getString("pptUrl");
        String pointsJson = obj.getString("points");
        String downloadName = obj.getString("downloadName");
        logger.info("pageSize=====>" + pageSize);
        logger.info("pptUrl=====>" + pptUrl);
        logger.info("downloadName=====>" + downloadName);
        List<Point> points = JSON.parseArray(pointsJson, Point.class);
        logger.info("points==size===>" + points.size());

        String filePath = saveExportPpt(points, pageSize, pptUrl);

        logger.info("filePath==========>{}" + filePath);

        String url = "";
        /**
         * 上传生成好的PPT文件到OSS中
         * 方便用户下载
         */
        if (StringUtils.isNotBlank(filePath)) {
            url = OssUtils.saveTempFile(filePath, downloadName);
        }
        logger.info("saveTempFile===url==>" + url);

        response.setStatus(200);
        OutputStream out = response.getOutputStream();
        out.write(url.getBytes());
        out.flush();
        out.close();
    }

  

    /**
     业务代码，生成PPT文件
     */
    public String saveExportPpt(List<Point> points, Integer pageSize, String pptUrl) {
        try {
            File file = File.createTempFile(System.nanoTime() + "", ".pptx");
            String absolutePath = file.getAbsolutePath();
            logger.info("file=====length===>" + file.length());
            return absolutePath;
        } catch (Exception e) {
            logger.info("Exception" + e.toString());
        }
        return null;
    }

    /**
     * 从OSS获取PPT模板，生成PPT模板类
     * @param pptUrl
     * @return
     */
    private XMLSlideShow getSlideShow(String pptUrl) {
        File pptFile = null;
        try {
            pptFile = File.createTempFile(System.nanoTime() + ".", StringUtils.substringAfterLast(pptUrl, "."));

            /**
             * 通过OSS SDK获取模板文件到函数计算服务器
             */
            OssUtils.getImage(pptUrl, pptFile);

            logger.info("pptFile==getAbsolutePath===>" + pptFile.getAbsolutePath());
            logger.info("pptFile==exists===>" + pptFile.exists());
            logger.info("pptFile==length===>" + pptFile.length());

        } catch (Exception e) {
            e.printStackTrace();
        }
        if (pptFile == null || !pptFile.exists()) {
            return null;
        }
        try {
            InputStream is = new FileInputStream(pptFile);
            XMLSlideShow slideShow = new XMLSlideShow(is);
            is.close();
            return slideShow;
        } catch (Exception e1) {

        }
        return null;
    }

    /**
     * 通过OSS SDK获取PPT中需要添加的图片到函数计算服务器本地
     */
    private byte[] getImage(String imageUrl) {
        try {
            File destFile = File.createTempFile("temp", "." + StringUtils.substringAfterLast(imageUrl, "."));
            OssUtils.getImage(imageUrl, destFile);
            byte[] pictureData = FileUtils.readFileToByteArray(destFile);
            destFile.deleteOnExit();
            return pictureData;
        } catch (Exception e) {
            return null;
        }
    }

}