#232 基于Hystrix的系统保护，Day2. 演示

examples/quickstart/src/main/java/org/springside/examples/quickstart/rest/RestExceptionHandler.java

@@ -2,7 +2,9 @@
 
 import javax.validation.ConstraintViolationException;
 
+import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.bind.annotation.ExceptionHandler;
@@ -15,7 +17,9 @@ public class RestExceptionHandler extends ResponseEntityExceptionHandler {
 
 	@ExceptionHandler(value = { ConstraintViolationException.class })
 	public final ResponseEntity<?> handleException(ConstraintViolationException ex, WebRequest request) {
-		return new ResponseEntity(BeanValidators.extractPropertyAndMessage(ex.getConstraintViolations()),
-				HttpStatus.BAD_REQUEST);
+		String body = BeanValidators.extractPropertyAndMessage(ex.getConstraintViolations()).toString();
+		HttpHeaders headers = new HttpHeaders();
+		headers.setContentType(MediaType.TEXT_PLAIN);
+		return handleExceptionInternal(ex, body, null, HttpStatus.BAD_REQUEST, request);
 	}
 }

examples/showcase/src/main/java/org/springside/examples/showcase/demos/hystrix/resource/ResourceController.java

@@ -1,5 +1,6 @@
 package org.springside.examples.showcase.demos.hystrix.resource;
 
+import org.hibernate.service.spi.ServiceException;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.PathVariable;
@@ -18,7 +19,7 @@
  */
 @Controller
 public class ResourceController {
-	public static final int TIMEOUT = 20000;
+	public static final int TIMEOUT = 10000;
 
 	@Autowired
 	private AccountEffectiveService accountService;
@@ -39,7 +40,7 @@ public UserDTO getUser(@PathVariable("id") Long id) {
 		}
 
 		if ("fail".equals(HystrixController.status)) {
-			throw new RuntimeException("Server Exception");
+			throw new ServiceException("Server Exception");
 		}
 
 		return null;

examples/showcase/src/main/java/org/springside/examples/showcase/demos/hystrix/service/GetUserCommand.java

@@ -5,6 +5,8 @@
 
 import com.netflix.hystrix.HystrixCommand;
 import com.netflix.hystrix.HystrixCommandGroupKey;
+import com.netflix.hystrix.HystrixCommandKey;
+import com.netflix.hystrix.HystrixCommandProperties;
 
 public class GetUserCommand extends HystrixCommand<UserDTO> {
 
@@ -13,7 +15,20 @@ public class GetUserCommand extends HystrixCommand<UserDTO> {
 	private RestTemplate restTemplate = new RestTemplate();
 
 	protected GetUserCommand(Long id) {
-		super(HystrixCommandGroupKey.Factory.asKey("ExampleGroup"));
+
+		super(Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey("ExampleGroup"))
+				.andCommandKey(HystrixCommandKey.Factory.asKey("GetUserCommand"))
+				.andCommandPropertiesDefaults(HystrixCommandProperties.Setter()
+				// 线程超时，默认为1秒,设为3秒，
+						.withExecutionIsolationThreadTimeoutInMilliseconds(3000)
+						// 至少多少请求在rolling window内发生，开始触发短路的计算，默认为20, 设为3
+						.withCircuitBreakerRequestVolumeThreshold(3)
+						// 多少百分比的fail在rolling windows内发生，计算为短路。默认为50%
+						.withCircuitBreakerErrorThresholdPercentage(50)
+						// 被置成短路后，多久才会重新尝试访问资源。默认为5秒，设为10秒
+						.withCircuitBreakerSleepWindowInMilliseconds(10000)
+						// rolling windows 长度，默认为10秒，设为20秒。
+						.withMetricsRollingStatisticalWindowInMilliseconds(20000)));
 		this.id = id;
 	}
 

examples/showcase/src/main/java/org/springside/examples/showcase/demos/hystrix/service/ServiceController.java

@@ -1,21 +1,33 @@
 package org.springside.examples.showcase.demos.hystrix.service;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpStatus;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.ResponseBody;
+import org.springside.examples.showcase.webservice.rest.RestException;
 import org.springside.examples.showcase.webservice.rest.UserDTO;
 
 /**
  * 使用Hystrix访问资源的服务。
  */
 @Controller
 public class ServiceController {
+	private static Logger logger = LoggerFactory.getLogger(ServiceController.class);
+
 	@RequestMapping(value = "/hystrix/service/{id}", method = RequestMethod.GET)
 	@ResponseBody
 	public UserDTO getUser(@PathVariable("id") Long id) {
 		GetUserCommand command = new GetUserCommand(id);
-		return command.execute();
+
+		try {
+			return command.execute();
+		} catch (Exception e) {
+			logger.error(e.getMessage(), e);
+			throw new RestException(HttpStatus.SERVICE_UNAVAILABLE);
+		}
 	}
 }

examples/showcase/src/main/java/org/springside/examples/showcase/webservice/rest/RestException.java

@@ -0,0 +1,20 @@
+package org.springside.examples.showcase.webservice.rest;
+
+import org.springframework.http.HttpStatus;
+
+public class RestException extends RuntimeException {
+
+	public HttpStatus status;
+
+	public RestException() {
+	}
+
+	public RestException(HttpStatus status) {
+		this.status = status;
+	}
+
+	public RestException(HttpStatus status, String message) {
+		super(message);
+		this.status = status;
+	}
+}

examples/showcase/src/main/java/org/springside/examples/showcase/webservice/rest/RestExceptionHandler.java

@@ -0,0 +1,37 @@
+package org.springside.examples.showcase.webservice.rest;
+
+import javax.validation.ConstraintViolationException;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.context.request.WebRequest;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
+import org.springside.modules.beanvalidator.BeanValidators;
+
+@ControllerAdvice
+public class RestExceptionHandler extends ResponseEntityExceptionHandler {
+
+	@ExceptionHandler(value = { ConstraintViolationException.class })
+	public final ResponseEntity<?> handleException(ConstraintViolationException ex, WebRequest request) {
+		String body = BeanValidators.extractPropertyAndMessage(ex.getConstraintViolations()).toString();
+		HttpHeaders headers = new HttpHeaders();
+		headers.setContentType(MediaType.TEXT_PLAIN);
+		return handleExceptionInternal(ex, body, headers, HttpStatus.BAD_REQUEST, request);
+	}
+
+	@ExceptionHandler(value = { RestException.class })
+	public final ResponseEntity<?> handleException(RestException ex, WebRequest request) {
+		String body = ex.getMessage();
+
+		HttpHeaders headers = new HttpHeaders();
+		headers.setContentType(MediaType.TEXT_PLAIN);
+
+		HttpStatus status = (ex.status != null) ? ex.status : HttpStatus.INTERNAL_SERVER_ERROR;
+
+		return handleExceptionInternal(ex, body, headers, status, request);
+	}
+}

examples/showcase/src/main/webapp/WEB-INF/views/story/hystrix.jsp

@@ -15,13 +15,17 @@
 
 <body>
 	<h1>Hystrix 演示</h1>
+
+	<p><a href="https://github.com/Netflix/Hystrix" target="_blank">Netflix Hystrix</a> 是一个延迟与容错类库，通过独立访问远程系统、服务和第三方库的节点，在复杂的分布式系统里停止雪崩及提供恢复能力。</p>
 
 	<h2>当前资源状态为<%= HystrixController.status %></h2>
 	<ul>
 		<li><a href="${ctx}/story/hystrix/timeout">切换为Timeout</a></li>
 		<li><a href="${ctx}/story/hystrix/fail">切换为Fail</a></li>
 		<li><a href="${ctx}/story/hystrix/normal">切换为Normal</a></li>
 	</ul>
-
+
+	<h2>访问Hystrix服务</h2>
+	<a href="${ctx}/hystrix/service/1" target="_blank"> ${ctx}/hystrix/service/1</a>
 </body>
 </html>