图片缩略图功能
需要对图片生产缩略图，压缩并保存到不同的介质中。输入端可能是本地图片，也可能是网络图片。保存的位置可能是本地，也有可能是第三方的minio、阿里云oss、七牛云oss。并且这些途径可能随时扩展。为了设计的灵活性，这里就要把输入可输出抽象出来，应用层通过抽象层结偶。这样的抽象和实现分离，实现层可以自由扩展，而应用层依赖于抽象层相对稳定。
整体结构是这样的
代码结构是这样的
整体实现是这样的
ThumbLoad 图片的输入信息⬇︎⬇︎⬇︎
点击查看代码
package com.supremind.modules.news.service.impl.thumb;import com.supremind.modules.news.entity.ImageActionVo;
import lombok.Getter;
import lombok.Setter;
import lombok.extern.slf4j.Slf4j;import javax.validation.constraints.NotBlank;
import java.net.HttpURLConnection;
import java.net.URL;/*** 图片载入* 1)图片载入过程不涉及到异常处理，异常自行处理，一切结果以isSuccess为准，具体消息去message*/
@Slf4j
public abstract class ThumbLoad {@Setter@Getterprotected ThumbSave thumbSave;public ThumbLoad(ThumbSave thumbSave) {this.thumbSave = thumbSave;}@Getter@Setter/*load载入结果,默认为false,免去每次异常都赋值.只有操作成功后进行赋值true*/protected Boolean isSuccess=false;@Getter@Setter/*错误消息提醒*/protected String message =null;public abstract ImageActionVo thumb(String filePath);/*** 验证网络资源是否可以访问* @param url 网络资源地址* @param checkIsImage 是否强制检测为image类型的资源* @return*/protected Boolean checkUrlIsAccess(@NotBlank String url, Boolean checkIsImage){log.debug("checkUrlIsAccess start ...");log.debug("url:{}",url);URL netUrl = null;HttpURLConnection httpURLConnection =null;Boolean result = true;try {netUrl = new URL(url);httpURLConnection = (HttpURLConnection)netUrl.openConnection();httpURLConnection.setConnectTimeout(2000);if (httpURLConnection.getResponseCode()==200) {String contentType = httpURLConnection.getContentType();if (checkIsImage){if (!contentType.split("/")[0].equals("image")) {result = false;}}}else{result = false;}}catch (Exception e){log.error("e :{}", e);result = false;}finally {if (httpURLConnection != null) {httpURLConnection.disconnect();}}log.debug("checkUrlIsAccess end.");return result;}}ThumbSave 图片的输入信息⬇︎⬇︎⬇︎
点击查看代码
package com.supremind.modules.news.service.impl.thumb;import com.supremind.config.FileServerConfig;
import lombok.AllArgsConstructor;
import lombok.Data;
import org.springframework.beans.factory.annotation.Autowired;import java.io.InputStream;/*** 文件保存* 1)文件保存到fileServer ,thumburi是fileserver返回的可以直接访问的地址* 2)文件保存本地，thumburi表示本地文件的完整路径* 注：* 1.文件保存类型取决与具体实现，但结构保持一致。最外层控制逻辑，是isSuccess.* 2.为了实现最大程度的复用，这里选择使用inputStream 进行对接saveImage.* 3.在扩展save策略时，注意异常处理，结果都从ImageSaveResult体现说明*/
public abstract class ThumbSave {@Autowiredprotected FileServerConfig fileServerConfig;protected String bucketName = "thumb_images"; //file server bucketeprotected String saveUri; //处理后的文件保存路protected Integer width; //图片压缩宽度protected Integer height; //图片压缩高度public ThumbSave(String saveUri, Integer width, Integer height) {this.saveUri = saveUri;this.width = width;this.height = height;}abstract ImageSaveResult save(InputStream imageInputStream);@Data@AllArgsConstructorclass ImageSaveResult {private Boolean isSuccess = false; //操作是否成功private String thumbUri; //缩略图文件地址private String msg; //消息}}下面是具体实现
LocalThumbSave 本地保存⬇︎⬇︎⬇︎
点击查看代码
package com.supremind.modules.news.service.impl.thumb;import lombok.extern.slf4j.Slf4j;
import net.coobird.thumbnailator.Thumbnails;import java.io.IOException;
import java.io.InputStream;/*** 本地保存文件*/
@Slf4j
public class LocalThumbSave extends ThumbSave {public LocalThumbSave(String saveUri, Integer width, Integer height) {super(saveUri, width, height);}public ImageSaveResult save(InputStream imageInputStream) {try {Thumbnails.of(imageInputStream).size(width,height).toFile(saveUri);return new ImageSaveResult(true,saveUri,null);} catch (IOException e) {log.error("Thumbnails toFiles error:{}",e);return new ImageSaveResult(false, null, e.getMessage());}}
}FileServerThumbSave file server保存文件（这里的fileserver又做了一层抽象，可以接入不同的第三方）⬇︎⬇︎⬇︎
点击查看代码
package com.supremind.modules.news.service.impl.thumb;import com.supremind.common.SpringContextUtil;
import com.supremind.common.utils.R;
import com.supremind.modules.news.feign.FileFeignClient;
import com.supremind.modules.news.service.impl.G;
import lombok.Cleanup;
import lombok.extern.slf4j.Slf4j;
import net.coobird.thumbnailator.Thumbnails;
import org.springframework.http.MediaType;
import org.springframework.mock.web.MockMultipartFile;import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;/*** file server保存文件*/
@Slf4j
public class FileServerThumbSave extends ThumbSave {public FileServerThumbSave(String saveUri, Integer width, Integer height) {super(saveUri, width, height);}public ImageSaveResult save(final InputStream imageInputStream) {log.debug("FileServerSaveImage start ......");try {@Cleanup ByteArrayOutputStream outputStream = new ByteArrayOutputStream();Thumbnails.of(imageInputStream).size(width,height).toOutputStream(outputStream);@Cleanup ByteArrayInputStream swapStream = new ByteArrayInputStream(outputStream.toByteArray());FileFeignClient fileFeignClient = SpringContextUtil.getBean(FileFeignClient.class);MockMultipartFile mockMultipartFile = new MockMultipartFile("file.jpg","file.jpg", MediaType.IMAGE_JPEG_VALUE,swapStream);R image = fileFeignClient.upload(bucketName, mockMultipartFile);log.debug("image :{}", image);if (G.isSuccess(image)) {return new ImageSaveResult(true, image.get("data").toString(), null);}else{return new ImageSaveResult(false, null, G.getMsg(image));}} catch (IOException e) {log.error("FileServerSaveImage IOException :{}",e);return new ImageSaveResult(false, null, e.getMessage());}finally {log.debug("FileServerSaveImage end");}}
}UriThumbLoad 读取本地资源文件⬇︎⬇︎⬇︎
点击查看代码
package com.supremind.modules.news.service.impl.thumb;import com.supremind.modules.news.entity.ImageActionVo;
import com.supremind.modules.news.enums.ErrorMsgEnum;
import lombok.Cleanup;
import lombok.extern.slf4j.Slf4j;import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;/*** 本地文件载入*/
@Slf4j
public class UriThumbLoad extends ThumbLoad {public UriThumbLoad(ThumbSave thumbSave) {super(thumbSave);}public ImageActionVo thumb(String filePath) {//文件检查File file = new File(filePath);if (!file.exists()) {return new ImageActionVo(filePath,false,null, ErrorMsgEnum.FILE_NOT_FIND.getValue());}try {@Cleanup InputStream inputStream = new FileInputStream(file);ThumbSave.ImageSaveResult save = thumbSave.save(inputStream);return new ImageActionVo(filePath, save.getIsSuccess(), save.getThumbUri(), save.getMsg());} catch (Exception e) {log.error("FileNotFoundException :{}",e);return new ImageActionVo(filePath,false,null,e.getMessage());}}}点击查看代码
package com.supremind.modules.news.service.impl.thumb;import com.supremind.modules.news.entity.ImageActionVo;
import com.supremind.modules.news.enums.ErrorMsgEnum;
import lombok.Cleanup;
import lombok.extern.slf4j.Slf4j;import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;/*** 网络图片载入*/
@Slf4j
public class UrlThumbLoad extends ThumbLoad {public UrlThumbLoad(ThumbSave thumbSave) {super(thumbSave);}public ImageActionVo thumb(String filePath) {HttpURLConnection urlConnection;if (!checkUrlIsAccess(filePath,true)) {return new ImageActionVo(filePath, false, null, ErrorMsgEnum.FILE_NOT_ACCESS.getValue());}try {URL url = new URL(filePath);urlConnection = (HttpURLConnection)url.openConnection();urlConnection.setConnectTimeout(5000);@Cleanup InputStream inputStream = urlConnection.getInputStream();ThumbSave.ImageSaveResult save = thumbSave.save(inputStream);return new ImageActionVo(filePath, save.getIsSuccess(), save.getThumbUri(),save.getMsg());} catch (Exception e) {log.error("FileNotFoundException :{}",e);return new ImageActionVo(filePath,false,null,e.getMessage());}}}文件压缩也是同样的实现
