OSS上传文件返回前端上传进度三种方式

- 日理万妓 2022-12-29 04:40 868阅读 0赞

一、采用前端定时轮询请求接口

注意：采用session存放文件上传进度数据，适合jsp或者模板引擎页面，但是如果前后的分离，请采用redis或者MQ(消息队列)方式，将进度存入仓库中，然后通过标识读取数据，完成之后请重置或者删除标识。

1.1、上传文件

  1. @Value("${oss.endpoint}")
  2.     private String endpoint;
  4.     @Value("${oss.accessKeyId}")
  5.     private String accessKeyId;
  7.     @Value("${oss.accessKeySecret}")
  8.     private String accessKeySecret;
  10.     @Value("${oss.bucketName}")
  11.     private String bucketName;
  13.     @PostMapping("/upload")
  14.     public Object doUpload(@RequestParam("file") MultipartFile file, HttpServletRequest request) { 
  15.         if (file == null || file.isEmpty()) { 
  16.             return BaseResponse.fail("上传的文件是空文件!");
  17.         }
  18.         String fileName = file.getOriginalFilename();
  19.         FileUtils utils = new FileUtils();
  20.         File files = null;
  21.         try { 
  22.             files = File.createTempFile("tmp", null);
  23.             file.transferTo(files);
  24.             files.deleteOnExit();
  25.         } catch (Exception e) { 
  26.            log.error("流转文件失败：{}",e);
  27.         }
  28.         String url = utils.doUpload(fileName, files, endpoint, accessKeyId, accessKeySecret, bucketName, request.getSession());
  29.         Map<String, Object> map = new HashMap<>(1);
  30.         map.put("url", url);
  31.         map.put("fileName", fileName);
  32.         return map;
  33.     }

1.2、获取进度

  1. /** * 获取进度数据 * @param request * @return */
  2.  @GetMapping("/percent")
  3.     public Object getUploadPercent(HttpServletRequest request){ 
  4.         HttpSession session = request.getSession();
  5.         int percent = session.getAttribute("upload_percent") == null ? 0:  (Integer)session.getAttribute("upload_percent");
  6.         Map<String, Object> map = new HashMap<>(1);
  7.         map.put("percent", percent);
  8.         return map;
  9.     }
  11.     /** * 重置上传进度 * @param request */
  12.     @GetMapping("/percent/reset")
  13.     public void resetPercent(HttpServletRequest request){ 
  14.         HttpSession session = request.getSession();
  15.         session.setAttribute("upload_percent",0);
  16.     }

1.3、上传文件工具类

  1. import com.aliyun.oss.ClientConfiguration;
  2. import com.aliyun.oss.OSSClient;
  3. import com.aliyun.oss.common.comm.Protocol;
  4. import com.aliyun.oss.model.PutObjectRequest;
  5. import lombok.extern.slf4j.Slf4j;
  7. import javax.servlet.http.HttpSession;
  8. import java.io.*;
  9. import java.net.URL;
  10. import java.util.Date;
  11. import java.util.concurrent.TimeUnit;
  13. @Slf4j
  14. public class FileUtils { 
  16.  public String doUpload(String key, File files, String endpoint, String accessKeyId, String accessKeySecret, String bucketName, HttpSession session) { 
  17.         String keys = "test/"+key;
  18.         try { 
  19.             ClientConfiguration config = new ClientConfiguration();
  20.             config.setProtocol(Protocol.HTTPS);
  21.             OSSClient ossClient = new OSSClient(endpoint, accessKeyId, accessKeySecret, config);
  22.             ossClient.putObject(new PutObjectRequest(bucketName, keys, files).withProgressListener(new PutObjectProgressListener(session)));
  23.             Date expiration = new Date(System.currentTimeMillis() + EXPIRE_TIME);
  24.             URL url = ossClient.generatePresignedUrl(bucketName, keys, expiration);
  25.             ossClient.shutdown();
  26.             return String.valueOf(url);
  27.         } catch (Exception e) { 
  28.             log.error(e.getMessage(), e);
  29.             throw new IllegalStateException("文件上传到阿里云OSS服务报错!", e);
  30.         }
  31.     }
  32.  }

1.4、获取进度工具类

  1. import com.aliyun.oss.event.ProgressEvent;
  2. import com.aliyun.oss.event.ProgressEventType;
  3. import com.aliyun.oss.event.ProgressListener;
  4. import lombok.extern.slf4j.Slf4j;
  6. import javax.servlet.http.HttpSession;
  8. /** * ossClient.putObject, ossClient.getObject, ossClient.uploadPart方法支持进度条功能. * ossClient.uploadFile和ossClient.downloadFile方法不支持进度条功能. * 简单上传进度条监听器 * https://help.aliyun.com/document_detail/84796.html?spm=a2c4g.11186623.6.791.40554d83cDiWSN */
  9. @Slf4j
  10. public class PutObjectProgressListener implements ProgressListener { 
  12.     private long bytesWritten = 0;
  13.     private long totalBytes = -1;
  14.     private HttpSession session;
  15.     private boolean succeed = false;
  16.     private int percent = 0;
  18.     public PutObjectProgressListener(HttpSession mSession) { 
  19.         this.session = mSession;
  20.         session.setAttribute("upload_percent", percent);
  21.     }
  23.     @Override
  24.     public void progressChanged(ProgressEvent progressEvent) { 
  25.         long bytes = progressEvent.getBytes();
  26.         ProgressEventType eventType = progressEvent.getEventType();
  27.         switch (eventType) { 
  28.             case TRANSFER_STARTED_EVENT:
  29.                 log.debug("Start to upload......");
  30.                 break;
  31.             case REQUEST_CONTENT_LENGTH_EVENT:
  32.                 this.totalBytes = bytes;
  33.                 log.debug(this.totalBytes + " bytes in total will be uploaded to OSS");
  34.                 break;
  36.             case REQUEST_BYTE_TRANSFER_EVENT:
  37.                 this.bytesWritten += bytes;
  38.                 if (this.totalBytes != -1) { 
  39.                     int percent = (int)(this.bytesWritten * 100.0 / this.totalBytes);
  40.                     log.debug(bytes + " bytes have been written at this time, upload progress: " + percent + "%(" + this.bytesWritten + "/" + this.totalBytes + ")");
  41.                     session.setAttribute("upload_percent", percent);
  42.                 } else { 
  43.                     log.debug(bytes + " bytes have been written at this time, upload ratio: unknown" + "(" + this.bytesWritten + "/...)");
  44.                 }
  45.                 break;
  46.             case TRANSFER_COMPLETED_EVENT:
  47.                 this.succeed = true;
  48.                 log.debug("Succeed to upload, " + this.bytesWritten + " bytes have been transferred in total");
  49.                 break;
  50.             case TRANSFER_FAILED_EVENT:
  51.                 log.debug("Failed to upload, " + this.bytesWritten + " bytes have been transferred");
  52.                 break;
  53.             default:
  54.                 break;
  55.         }
  56.     }
  58.     public boolean isSucceed(){ 
  59.         return succeed;
  60.     }
  61. }

二、采用stomp+websocket推送模式

2.1、依赖

  1. <dependency>
  2.             <groupId>org.springframework</groupId>
  3.             <artifactId>spring-messaging</artifactId>
  4.             <version>5.2.6.RELEASE</version>
  5.         </dependency>
  6.         <dependency>
  7.             <groupId>org.springframework</groupId>
  8.             <artifactId>spring-websocket</artifactId>
  9.             <version>5.1.8.RELEASE</version>
  10.         </dependency>

2.2、客户端配置

  1. import org.springframework.context.annotation.Configuration;
  2. import org.springframework.messaging.simp.config.MessageBrokerRegistry;
  3. import org.springframework.web.socket.config.annotation.AbstractWebSocketMessageBrokerConfigurer;
  4. import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
  5. import org.springframework.web.socket.config.annotation.StompEndpointRegistry;
  7. //注解开启STOMP协议来传输基于代理的消息，此时控制器支持使用@MessageMapping
  8. @Configuration
  9. @EnableWebSocketMessageBroker
  10. public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer { 
  12.     @Override
  13.     public void configureMessageBroker(MessageBrokerRegistry config) { 
  14.         //topic用来广播，user用来实现p2p
  15.         config.enableSimpleBroker("/topic","/user");
  16.     }
  18.     @Override
  19.     public void registerStompEndpoints(StompEndpointRegistry registry) { 
  20.         registry.addEndpoint("/webServer").withSockJS();
  21.         //注册两个STOMP的endpoint，分别用于广播和点对点
  22.         registry.addEndpoint("/queueServer").withSockJS();
  23.     }
  25. }

2.3、上传文件

  1. @Value("${oss.endpoint}")
  2.     private String endpoint;
  4.     @Value("${oss.accessKeyId}")
  5.     private String accessKeyId;
  7.     @Value("${oss.accessKeySecret}")
  8.     private String accessKeySecret;
  10.     @Value("${oss.bucketName}")
  11.     private String bucketName;
  13.     @PostMapping("/upload")
  14.     public Object doUpload(@RequestParam("file") MultipartFile file, HttpServletRequest request) { 
  15.         if (file == null || file.isEmpty()) { 
  16.             return BaseResponse.fail("上传的文件是空文件!");
  17.         }
  18.         String fileName = file.getOriginalFilename();
  19.         FileUtils utils = new FileUtils();
  20.         File files = null;
  21.         try { 
  22.             files = File.createTempFile("tmp", null);
  23.             file.transferTo(files);
  24.             files.deleteOnExit();
  25.         } catch (Exception e) { 
  26.            log.error("流转文件失败：{}",e);
  27.         }
  28.         String url = utils.doUpload(fileName, files, endpoint, accessKeyId, accessKeySecret, bucketName, request.getSession());
  29.         Map<String, Object> map = new HashMap<>(1);
  30.         map.put("url", url);
  31.         map.put("fileName", fileName);
  32.         return map;
  33.     }

2.4、上传文件工具类

  1. import com.aliyun.oss.ClientConfiguration;
  2. import com.aliyun.oss.OSSClient;
  3. import com.aliyun.oss.common.comm.Protocol;
  4. import com.aliyun.oss.model.PutObjectRequest;
  5. import lombok.extern.slf4j.Slf4j;
  7. import javax.servlet.http.HttpSession;
  8. import java.io.*;
  9. import java.net.URL;
  10. import java.util.Date;
  11. import java.util.concurrent.TimeUnit;
  13. @Slf4j
  14. public class FileUtils { 
  16.  public String doUpload(String key, File files, String endpoint, String accessKeyId, String accessKeySecret, String bucketName, HttpSession session) { 
  17.         String keys = "test/"+key;
  18.         try { 
  19.             ClientConfiguration config = new ClientConfiguration();
  20.             config.setProtocol(Protocol.HTTPS);
  21.             OSSClient ossClient = new OSSClient(endpoint, accessKeyId, accessKeySecret, config);
  22.             ossClient.putObject(new PutObjectRequest(bucketName, keys, files).withProgressListener(new PutObjectProgressListener(session)));
  23.             Date expiration = new Date(System.currentTimeMillis() + EXPIRE_TIME);
  24.             URL url = ossClient.generatePresignedUrl(bucketName, keys, expiration);
  25.             ossClient.shutdown();
  26.             return String.valueOf(url);
  27.         } catch (Exception e) { 
  28.             log.error(e.getMessage(), e);
  29.             throw new IllegalStateException("文件上传到阿里云OSS服务报错!", e);
  30.         }
  31.     }
  32.  }

2.5、推送方式

  1. import com.aliyun.oss.event.ProgressEvent;
  2. import com.aliyun.oss.event.ProgressEventType;
  3. import com.aliyun.oss.event.ProgressListener;
  4. import lombok.extern.slf4j.Slf4j;
  5. import org.springframework.beans.factory.annotation.Autowired;
  6. import org.springframework.messaging.simp.SimpMessagingTemplate;
  7. import org.springframework.stereotype.Service;
  9. import javax.servlet.http.HttpSession;
  11. /** * ossClient.putObject, ossClient.getObject, ossClient.uploadPart方法支持进度条功能. * ossClient.uploadFile和ossClient.downloadFile方法不支持进度条功能. * 简单上传进度条监听器 * https://help.aliyun.com/document_detail/84796.html?spm=a2c4g.11186623.6.791.40554d83cDiWSN */
  12. @Slf4j
  13. @Service
  14. public class PutObjectProgressListener implements ProgressListener { 
  16.     @Autowired
  17.     public SimpMessagingTemplate simpMessagingTemplate;
  19.     private long bytesWritten = 0;
  20.     private long totalBytes = -1;
  21.     private HttpSession session;
  22.     private boolean succeed = false;
  23.     private int percent = 0;
  25.     public PutObjectProgressListener(HttpSession mSession) { 
  26.         this.session = mSession;
  27.     }
  29.     @Override
  30.     public void progressChanged(ProgressEvent progressEvent) { 
  31.         long bytes = progressEvent.getBytes();
  32.         ProgressEventType eventType = progressEvent.getEventType();
  33.         switch (eventType) { 
  34.             case TRANSFER_STARTED_EVENT:
  35.                 log.debug("Start to upload......");
  36.                 break;
  37.             case REQUEST_CONTENT_LENGTH_EVENT:
  38.                 this.totalBytes = bytes;
  39.                 log.debug(this.totalBytes + " bytes in total will be uploaded to OSS");
  40.                 break;
  42.             case REQUEST_BYTE_TRANSFER_EVENT:
  43.                 this.bytesWritten += bytes;
  44.                 if (this.totalBytes != -1) { 
  45.                     int percent = (int)(this.bytesWritten * 100.0 / this.totalBytes);
  46.                     log.debug(bytes + " bytes have been written at this time, upload progress: " + percent + "%(" + this.bytesWritten + "/" + this.totalBytes + ")");
  47.                     // 通过websocket 推送
  48.                     Map<String, Object> map = new HashMap<>(1);
  49.                     map.put("percent", percent);
  50.                     simpMessagingTemplate.convertAndSend("/topic/percent", map);
  51.                 } else { 
  52.                     log.debug(bytes + " bytes have been written at this time, upload ratio: unknown" + "(" + this.bytesWritten + "/...)");
  53.                 }
  54.                 break;
  55.             case TRANSFER_COMPLETED_EVENT:
  56.                 this.succeed = true;
  57.                 log.debug("Succeed to upload, " + this.bytesWritten + " bytes have been transferred in total");
  58.                 break;
  59.             case TRANSFER_FAILED_EVENT:
  60.                 log.debug("Failed to upload, " + this.bytesWritten + " bytes have been transferred");
  61.                 break;
  62.             default:
  63.                 break;
  64.         }
  65.     }
  67.     public boolean isSucceed(){ 
  68.         return succeed;
  69.     }
  70. }

三、采用Servlet3.1长轮询模式

3.1、长轮询获取进度

  1. /** * guava中的Multimap，多值map,对map的增强，一个key可以保持多个value */
  2.     private Multimap<String, DeferredResult<Object>> watchRequests = Multimaps.synchronizedSetMultimap(HashMultimap.create());
  5. /** * 前端长轮询 当接口返回304 一直请求 直到返回结果 */
  6.     @RequestMapping(value = "/watch", method = RequestMethod.GET, produces = "text/html")
  7.     public DeferredResult<Object> watch(HttpServletRequest request) { 
  8.         log.info("Request received");
  9.         ResponseEntity<Object> NOT_MODIFIED_RESPONSE = new ResponseEntity<>(HttpStatus.NOT_MODIFIED);
  10.         DeferredResult<Object> deferredResult = new DeferredResult<>(5000L, NOT_MODIFIED_RESPONSE);
  11.         /** * 当deferredResult完成时（不论是超时还是异常还是正常完成），移除watchRequests中相应的watch key */
  12.         deferredResult.onCompletion(() -> { 
  13.             log.info("remove key:" + request.getSession().getId());
  14.             watchRequests.remove(request.getSession().getId(), deferredResult);
  15.         });
  16.         deferredResult.onTimeout(()-> log.info("onTimeout()" ));
  17.         watchRequests.put(request.getSession().getId(), deferredResult);
  18.         log.info("Servlet thread released");
  19.         return deferredResult;
  20.     }
  22.     /** * 发布数据 请求接口方式 反射调用方式 * @param sessionId * @return */
  23.     @RequestMapping(value = "/publish", method = RequestMethod.GET, produces = "text/html")
  24.     public Object publish(@RequestParam("sessionId") String sessionId, @RequestParam("percent") Integer percent) { 
  25.         if (watchRequests.containsKey(sessionId)) { 
  26.             Collection<DeferredResult<Object>> deferredResults = watchRequests.get(sessionId);
  27.             //通知所有watch这个sessionId变更的长轮训配置变更结果
  28.             for (DeferredResult<Object> deferredResult : deferredResults) { 
  29.                 //deferredResult一旦执行了setResult()方法，就说明DeferredResult正常完成了，会立即把结果返回给客户端
  30.                 Map<String, Object> map = new HashMap<>(2);
  31.                 map.put("sessionId", sessionId);
  32.                 map.put("percent", percent);
  33.                 deferredResult.setResult(map);
  34.             }
  35.         }
  36.         Map<String, Object> map = new HashMap<>(2);
  37.         map.put("code", "success");
  38.         return map;
  39.     }

3.2、发布数据

  1. import com.aliyun.oss.event.ProgressEvent;
  2. import com.aliyun.oss.event.ProgressEventType;
  3. import com.aliyun.oss.event.ProgressListener;
  4. import lombok.extern.slf4j.Slf4j;
  5. import org.springframework.beans.factory.annotation.Autowired;
  6. import org.springframework.context.ApplicationContext;
  7. import org.springframework.stereotype.Component;
  9. import javax.servlet.http.HttpSession;
  10. import java.lang.reflect.Method;
  12. /** * ossClient.putObject, ossClient.getObject, ossClient.uploadPart方法支持进度条功能. * ossClient.uploadFile和ossClient.downloadFile方法不支持进度条功能. * 简单上传进度条监听器 * https://help.aliyun.com/document_detail/84796.html?spm=a2c4g.11186623.6.791.40554d83cDiWSN */
  13. @Slf4j
  14. @Component
  15. public class PutObjectProgressListener implements ProgressListener { 
  17.     @Autowired
  18.     private ApplicationContext applicationContext;
  20.     private long bytesWritten = 0;
  21.     private long totalBytes = -1;
  22.     private HttpSession session;
  23.     private boolean succeed = false;
  24.     private int percent = 0;
  26.     public PutObjectProgressListener(HttpSession mSession) { 
  27.         this.session = mSession;
  28.     }
  30.     @Override
  31.     public void progressChanged(ProgressEvent progressEvent) { 
  32.         long bytes = progressEvent.getBytes();
  33.         ProgressEventType eventType = progressEvent.getEventType();
  34.         switch (eventType) { 
  35.             case TRANSFER_STARTED_EVENT:
  36.                 log.debug("Start to upload......");
  37.                 break;
  38.             case REQUEST_CONTENT_LENGTH_EVENT:
  39.                 this.totalBytes = bytes;
  40.                 log.debug(this.totalBytes + " bytes in total will be uploaded to OSS");
  41.                 break;
  43.             case REQUEST_BYTE_TRANSFER_EVENT:
  44.                 this.bytesWritten += bytes;
  45.                 if (this.totalBytes != -1) { 
  46.                     int percent = (int)(this.bytesWritten * 100.0 / this.totalBytes);
  47.                     log.debug(bytes + " bytes have been written at this time, upload progress: " + percent + "%(" + this.bytesWritten + "/" + this.totalBytes + ")");
  48.                     publish(session.getId(), percent);
  49.                 } else { 
  50.                     log.debug(bytes + " bytes have been written at this time, upload ratio: unknown" + "(" + this.bytesWritten + "/...)");
  51.                 }
  52.                 break;
  53.             case TRANSFER_COMPLETED_EVENT:
  54.                 this.succeed = true;
  55.                 log.debug("Succeed to upload, " + this.bytesWritten + " bytes have been transferred in total");
  56.                 break;
  57.             case TRANSFER_FAILED_EVENT:
  58.                 log.debug("Failed to upload, " + this.bytesWritten + " bytes have been transferred");
  59.                 break;
  60.             default:
  61.                 break;
  62.         }
  63.     }
  65.     public boolean isSucceed(){ 
  66.         return succeed;
  67.     }
  69.     /** * 通过反射调用接口 */
  70.     private void publish(String sessionId, Integer percent) { 
  71.         Class<?> clazz = ReflectUtil.forName("cn.com.*.controller.upload.FileUploadController");
  72.         Object bean = applicationContext.getBean(clazz);
  73.         Method method = ReflectUtil.findMethod(clazz, "publish", String.class, Integer.class);
  74.         ReflectUtil.invokeMethod(method, bean, sessionId, percent);
  75.     }
  76. }

3.3、上传文件

  1. @Value("${oss.endpoint}")
  2.     private String endpoint;
  4.     @Value("${oss.accessKeyId}")
  5.     private String accessKeyId;
  7.     @Value("${oss.accessKeySecret}")
  8.     private String accessKeySecret;
  10.     @Value("${oss.bucketName}")
  11.     private String bucketName;
  13.     @PostMapping("/upload")
  14.     public Object doUpload(@RequestParam("file") MultipartFile file, HttpServletRequest request) { 
  15.         if (file == null || file.isEmpty()) { 
  16.             return BaseResponse.fail("上传的文件是空文件!");
  17.         }
  18.         String fileName = file.getOriginalFilename();
  19.         FileUtils utils = new FileUtils();
  20.         File files = null;
  21.         try { 
  22.             files = File.createTempFile("tmp", null);
  23.             file.transferTo(files);
  24.             files.deleteOnExit();
  25.         } catch (Exception e) { 
  26.            log.error("流转文件失败：{}",e);
  27.         }
  28.         String url = utils.doUpload(fileName, files, endpoint, accessKeyId, accessKeySecret, bucketName, request.getSession());
  29.         Map<String, Object> map = new HashMap<>(1);
  30.         map.put("url", url);
  31.         map.put("fileName", fileName);
  32.         return map;
  33.     }

3.4、上传文件工具类

  1. import com.aliyun.oss.ClientConfiguration;
  2. import com.aliyun.oss.OSSClient;
  3. import com.aliyun.oss.common.comm.Protocol;
  4. import com.aliyun.oss.model.PutObjectRequest;
  5. import lombok.extern.slf4j.Slf4j;
  7. import javax.servlet.http.HttpSession;
  8. import java.io.*;
  9. import java.net.URL;
  10. import java.util.Date;
  11. import java.util.concurrent.TimeUnit;
  13. @Slf4j
  14. public class FileUtils { 
  16.  public String doUpload(String key, File files, String endpoint, String accessKeyId, String accessKeySecret, String bucketName, HttpSession session) { 
  17.         String keys = "test/"+key;
  18.         try { 
  19.             ClientConfiguration config = new ClientConfiguration();
  20.             config.setProtocol(Protocol.HTTPS);
  21.             OSSClient ossClient = new OSSClient(endpoint, accessKeyId, accessKeySecret, config);
  22.             ossClient.putObject(new PutObjectRequest(bucketName, keys, files).withProgressListener(new PutObjectProgressListener(session)));
  23.             Date expiration = new Date(System.currentTimeMillis() + EXPIRE_TIME);
  24.             URL url = ossClient.generatePresignedUrl(bucketName, keys, expiration);
  25.             ossClient.shutdown();
  26.             return String.valueOf(url);
  27.         } catch (Exception e) { 
  28.             log.error(e.getMessage(), e);
  29.             throw new IllegalStateException("文件上传到阿里云OSS服务报错!", e);
  30.         }
  31.     }
  32.  }

3.5、反射工具

  1. import org.springframework.context.ApplicationContext;
  3. import java.beans.PropertyDescriptor;
  4. import java.lang.reflect.Method;
  6. /** * 反射调用工具类 */
  7. public final class ReflectUtil { 
  9.     /** * 调用Spring容器中bean的方法 * * @param applicationContext 容器对象 * @param methodDescriptor 方法描述符,类的全限定名#方法名称 * @param parameterTypes 方法参数类型列表 * @param params 方法参数列表 * @param <T> 返回的数据类型 * @return 调用结果 */
  10.     public static <T> T invoke(ApplicationContext applicationContext, String methodDescriptor,
  11.                                Class<?>[] parameterTypes, Object... params) { 
  12.         String[] array = methodDescriptor.split("#");
  13.         Class<?> beanClass = forName(array[0]);
  14.         Object bean = applicationContext.getBean(beanClass);
  15.         Method method = findMethod(beanClass, array[1], parameterTypes);
  16.         return invokeMethod(method, bean, params);
  17.     }
  19.     /** * 寻找类中的方法 * * @param targetClass 需要查找的类型 * @param methodName 方法名称 * @param parameterTypes 参数类型列表，必须严格一致 * @return 类中的方法 */
  20.     public static Method findMethod(Class<?> targetClass, String methodName, Class<?>... parameterTypes) { 
  21.         try { 
  22.             Method method = targetClass.getMethod(methodName, parameterTypes);
  23.             method.setAccessible(true);
  24.             return method;
  25.         } catch (Exception e) { 
  26.             throw new IllegalArgumentException(e);
  27.         }
  28.     }
  30.     /** * 反射调用方法 * * @param method 方法 * @param target 需要调用的对象 * @param parameters 方法参数 * @param <T> 返回的结果类型 * @return 调用结果 */
  31.     @SuppressWarnings("unchecked")
  32.     public static <T> T invokeMethod(Method method, Object target, Object... parameters) { 
  33.         try { 
  34.             return (T) method.invoke(target, parameters);
  35.         } catch (Exception e) { 
  36.             throw new IllegalArgumentException(e);
  37.         }
  38.     }
  40.     /** * 根据类的全限定名获取对应的class对象 * * @param className 类全限定名 * @param <T> 返回的class对象类型 * @return class对象 */
  41.     @SuppressWarnings("unchecked")
  42.     public static <T> Class<T> forName(String className) { 
  43.         try { 
  44.             return (Class<T>) Class.forName(className);
  45.         } catch (ClassNotFoundException e) { 
  46.             throw new IllegalArgumentException(e);
  47.         }
  48.     }
  50.     /** * 调用javaBean的get方法 * * @param target javaBean实体 * @param prop 属性名称 * @param classOfT 该属性对应的类型 * @param <T> 该属性对应的类型 * @return 调用结果 */
  51.     @SuppressWarnings("unchecked")
  52.     public static <T> T invokeGetter(Object target, String prop, Class<T> classOfT) { 
  53.         try { 
  54.             PropertyDescriptor pd = new PropertyDescriptor(prop, target.getClass());
  55.             Object value = pd.getReadMethod().invoke(target);
  56.             if (value == null) { 
  57.                 return null;
  58.             }
  59.             if (classOfT.isInstance(value)) { 
  60.                 return (T) value;
  61.             } else { 
  62.                 throw new IllegalArgumentException("属性: " + prop + " 的类型不是: " + classOfT);
  63.             }
  64.         } catch (Exception e) { 
  65.             throw new IllegalArgumentException(e);
  66.         }
  67.     }
  69.     private ReflectUtil() { 
  70.     }
  72. }

发表评论

表情：
评论列表 （有 0 条评论，868人围观）

还没有评论，来说两句吧...

相关阅读