java实现异步非阻塞的几种方式-同步阻塞调用
1. 同步阻塞调用
在讲异步非阻塞之前还是先来说明同步阻塞的调用吧。明白了同步阻塞的调用，才能更好的明白异步非阻塞的调用。以一个示例来说明吧，这是一个非常常见的程序间的调用。
我们的程序对外提供当前的用户的订单详细查询的接口，订单接口先调用用户服务，获取当前的用户信息；再调用商品接口获取商品的详细信息。
就以这样一个示例程序来说明吧。
假设这个订单服务调用用户服务的时间是2秒，调用商品服务的时间是3秒，订单服务自身的处理时间是1秒，那整个处理流程所需的时间就是2+3+1=6秒。
1.1 样例代码
用户服务:
/**
* 模拟的用户服务
*/
@RestController
@RequestMapping("/user")
public class UserService {
/** 测试预期值 */
public static final String CHECK_USER_ID = "1001";
@RequestMapping(
value = "/getUserInfo",
method = {RequestMethod.POST})
public ApiResponse getUserInfo(@RequestBody UserDTO input) {
if (null != input && CHECK_USER_ID.equals(input.getUserId())) {
UserDTO rsp = new UserDTO();
rsp.setName("bug_null");
rsp.setAddress("this is shanghai");
rsp.setUserId(CHECK_USER_ID);
ThreadUtils.sleep(5);
return ApiResponse.ok(rsp);
}
return ApiResponse.fail();
}
}
/**
* 用户的传输实体
*/
public class UserDTO {
/** 用户的id */
private String userId;
/** 用户的名称 */
private String name;
/** 地址信息 */
private String address;
......
}
/**
* 用户服务的springboot的入口
*/
@SpringBootApplication
public class UserApplication {
public static void main(String[] args) {
String[] argsNew = new String[] {"-- server.port=9000"};
SpringApplication.run(UserApplication.class, argsNew);
}
}商品服务
/**
* 用户模拟商品服务
*/
@RestController
@RequestMapping("/goods")
public class GoodsService {
/** 商品的id */
public static final String GOODS_ID = "2001";
@RequestMapping(
value = "/getGoodsInfo",
method = {RequestMethod.POST})
public ApiResponse getUserInfo(@RequestBody GoodsDTO input) {
if (null != input && GOODS_ID.equals(input.getDataId())) {
GoodsDTO goods = new GoodsDTO();
goods.setDataId(GOODS_ID);
goods.setGoodsPrice(1024);
goods.setMessage("这是一个苹果,apple,还被咬了一口");
ThreadUtils.sleep(10);
return ApiResponse.ok(goods);
}
return ApiResponse.fail();
}
}
/**
* 商品信息
*/
public class GoodsDTO {
/** 商品的id */
private String dataId;
/** 商品的价格 */
private Integer goodsPrice;
/** 商品的描述 */
private String message;
......
}
@SpringBootApplication
public class GoodsApplication {
public static void main(String[] args) {
String[] argsNew = new String[] {"-- server.port=9001"};
SpringApplication.run(GoodsApplication.class, argsNew);
}
}订单服务
@RestController
@RequestMapping("/order")
public class OrderServerFacade {
private Logger logger = LoggerFactory.getLogger(OrderServerFacade.class);
private Gson gson = new Gson();
/** 获取连接处理对象 */
private RestTemplate restTemplate = this.getRestTemplate();
@RequestMapping(
value = "/orderInfo",
method = {RequestMethod.POST})
public ApiResponse getUserInfo(@RequestBody OrderDTO order) {
logger.info("getUserInfo start {}", order);
// 用户信息
ClientUserDTO userRsp = this.getUserInfo(order.getUserId());
// 获取商品信息
ClientGoodsDTO clientGoodRsp = this.getGoods(order.getGoodId());
ThreadUtils.sleep(1);
OrderDTO orderRsp = this.builderRsp(userRsp, clientGoodRsp);
logger.info("getUserInfo start {} rsp {} orderRsp {} ", order, orderRsp);
// 构建结果的响应
return ApiResponse.ok(orderRsp);
}
/**
* 构造响应
*
* @param userInfo 用户信息
* @return 当前响应的用户信息
*/
private OrderDTO builderRsp(ClientUserDTO userInfo, ClientGoodsDTO goodsInfo) {
OrderDTO order = new OrderDTO();
order.setUserId(userInfo.getUserId());
order.setUserInfo(userInfo);
order.setGoodId(goodsInfo.getDataId());
order.setGoodsInfo(goodsInfo);
return order;
}
/**
* 获取用户的信息
*
* @param userId 用户的id
* @return 用户的信息
*/
private ClientUserDTO getUserInfo(String userId) {
logger.info("request get user info start {} ", userId);
ClientUserDTO clientUser = new ClientUserDTO();
clientUser.setUserId(userId);
HttpHeaders headers = new HttpHeaders();
// 将对象装入HttpEntity中
HttpEntity<ClientUserDTO> request = new HttpEntity<>(clientUser, headers);
ResponseEntity<String> result =
restTemplate.postForEntity("http://localhost:9000/user/getUserInfo", request, String.class);
if (HttpStatus.OK.value() == result.getStatusCodeValue()) {
ApiResponse<ClientUserDTO> data =
gson.fromJson(result.getBody(), new TypeToken<ApiResponse<ClientUserDTO>>() {}.getType());
// 如果操作成功，则返回结果
if (data.getResult()) {
ClientUserDTO rsp = data.getData();
logger.info("request get user info start {} rsp {} ", userId, rsp);
return rsp;
}
}
return null;
}
/**
* 获取商品信息
*
* @param dataId 商品信息
* @return 当前的用户的信息
*/
private ClientGoodsDTO getGoods(String dataId) {
logger.info("request goods start {} ", dataId);
ClientGoodsDTO clientGoods = new ClientGoodsDTO();
clientGoods.setDataId(dataId);
HttpHeaders headers = new HttpHeaders();
// 将对象装入HttpEntity中
HttpEntity<ClientGoodsDTO> request = new HttpEntity<>(clientGoods, headers);
ResponseEntity<String> result =
restTemplate.postForEntity(
"http://localhost:9001/goods/getGoodsInfo", request, String.class);
if (HttpStatus.OK.value() == result.getStatusCodeValue()) {
ApiResponse<ClientGoodsDTO> data =
gson.fromJson(
result.getBody(), new TypeToken<ApiResponse<ClientGoodsDTO>>() {}.getType());
// 如果操作成功，则返回结果
if (data.getResult()) {
ClientGoodsDTO goodsRsp = data.getData();
logger.info("request goods start {} , response {} ", dataId, goodsRsp);
return goodsRsp;
}
}
return null;
}
/**
* 获取连接管理对象
*
* @return
*/
private RestTemplate getRestTemplate() {
return new RestTemplate(getClientHttpRequestFactory());
}
/**
* 获取连接处理的工厂信息
*
* @return
*/
private SimpleClientHttpRequestFactory getClientHttpRequestFactory() {
SimpleClientHttpRequestFactory clientHttpRequestFactory = new SimpleClientHttpRequestFactory();
clientHttpRequestFactory.setConnectTimeout(25000);
clientHttpRequestFactory.setReadTimeout(25000);
return clientHttpRequestFactory;
}
}1.2 测试
执行单元测试:
/**
* 订单服务查询
*
*/
@RunWith(SpringRunner.class)
@SpringBootTest(
classes = {OrderApplication.class},
webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class TestOrderServerFacade {
@Autowired private Gson gson;
@Autowired protected TestRestTemplate restTemplate;
@Test
public void testUser() {
OrderDTO orderInfo = new OrderDTO();
orderInfo.setGoodId("2001");
orderInfo.setUserId("1001");
// 将对象装入HttpEntity中
HttpEntity<OrderDTO> request = new HttpEntity<>(orderInfo);
ResponseEntity<String> result =
restTemplate.postForEntity("/order/orderInfo", request, String.class);
Assert.assertEquals(HttpStatus.OK.value(), result.getStatusCodeValue());
ApiResponse<OrderDTO> data =
gson.fromJson(result.getBody(), new TypeToken<ApiResponse<OrderDTO>>() {}.getType());
System.out.println(data);
Assert.assertEquals(data.getResult(), Boolean.TRUE);
Assert.assertEquals(data.getCode(), APICodeEnum.SUCCESS.getErrorData().getCode());
Assert.assertNotNull(data.getData().getGoodsInfo());
Assert.assertNotNull(data.getData().getUserInfo());
}
}单元测试结果
从结果中耗时是16秒多。也证实了在开始时我的一个预期。同步阻塞式调用。由于只能顺序式调用。所以总时间就是所有调用的总时间相加。
1.3 分析
那当以客户端去调用服务时，客户端都在做什么呢？
这个时候可以借助于java的命令，拿到线程的栈信息和java堆信息
D:\run\dump>jps -l
13568 com.liujun.asynchronous.nonblocking.common.goods.GoodsApplication
1456 com.liujun.asynchronous.nonblocking.invoke.synchronous.OrderApplication
14848 org.jetbrains.jps.cmdline.Launcher
13604 org.jetbrains.kotlin.daemon.KotlinCompileDaemon
3508 com.liujun.asynchronous.nonblocking.common.user.UserApplication
5556 org.jetbrains.idea.maven.server.RemoteMavenServer36
6996
12840 org/netbeans/Main
14840
16092 sun.tools.jps.Jps
D:\run\dump>jstack -l 1456 > order.threaddump查看日志
2021-03-09 10:39:01.591 INFO 1456 --- [nio-9010-exec-6] c.l.a.n.i.synchronous.OrderServerFacade : getUserInfo start OrderDTO{userId='1001', userInfo=null, goodId='2001', goodsInfo=null}
2021-03-09 10:39:01.591 INFO 1456 --- [nio-9010-exec-6] c.l.a.n.i.synchronous.OrderServerFacade : request get user info start 1001
2021-03-09 10:39:03.596 INFO 1456 --- [nio-9010-exec-6] c.l.a.n.i.synchronous.OrderServerFacade : request get user info start 1001 rsp UserDTO{userId='1001', name='bug_null', address='this is shanghai'}
2021-03-09 10:39:03.597 INFO 1456 --- [nio-9010-exec-6] c.l.a.n.i.synchronous.OrderServerFacade : request goods start 2001
2021-03-09 10:39:13.603 INFO 1456 --- [nio-9010-exec-6] c.l.a.n.i.synchronous.OrderServerFacade : request goods start 2001 , response Goods{dataId='2001', goodsPrice=1024, message='这是一个苹果,apple,还被咬了一口'}
2021-03-09 10:39:14.603 INFO 1456 --- [nio-9010-exec-6] c.l.a.n.i.synchronous.OrderServerFacade : getUserInfo start OrderDTO{userId='1001', userInfo=null, goodId='2001', goodsInfo=null} rsp OrderDTO{userId='1001', userInfo=UserDTO{userId='1001', name='bug_null', address='this is shanghai'}, goodId='2001', goodsInfo=Goods{dataId='2001', goodsPrice=1024, message='这是一个苹果,apple,还被咬了一口'}} orderRsp {}从日志可以看任务是顺序式的调用。所以整个的调用时间就是所有执行的累加。
在本例中，配制的信息仅提取了线程的后15位信息，但已经可以定位到调用的线程了，现在去查看线程的调用栈信息.
"http-nio-9010-exec-6" #29 daemon prio=5 os_prio=0 tid=0x000000002129d000 nid=0x3ab0 runnable [0x000000002338c000]
java.lang.Thread.State: RUNNABLE
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.net.SocketInputStream.read(SocketInputStream.java:171)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:286)
at java.io.BufferedInputStream.read(BufferedInputStream.java:345)
- locked <0x00000006c5a0a588> (a java.io.BufferedInputStream)
at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:735)
at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:678)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1593)
- locked <0x00000006c5a0a638> (a sun.net.www.protocol.http.HttpURLConnection)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1498)
- locked <0x00000006c5a0a638> (a sun.net.www.protocol.http.HttpURLConnection)
at java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:480)
at org.springframework.http.client.SimpleClientHttpResponse.getRawStatusCode(SimpleClientHttpResponse.java:55)
at org.springframework.web.client.DefaultResponseErrorHandler.hasError(DefaultResponseErrorHandler.java:55)
at org.springframework.web.client.RestTemplate.handleResponse(RestTemplate.java:766)
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:736)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:670)
at org.springframework.web.client.RestTemplate.postForEntity(RestTemplate.java:445)
at com.liujun.asynchronous.nonblocking.invoke.synchronous.OrderServerFacade.getGoods(OrderServerFacade.java:124)
at com.liujun.asynchronous.nonblocking.invoke.synchronous.OrderServerFacade.getUserInfo(OrderServerFacade.java:50)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1039)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:660)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:118)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:853)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1587)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
- locked <0x00000006c59c6e10> (a org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Locked ownable synchronizers:
- <0x00000006c53ad000> (a java.util.concurrent.ThreadPoolExecutor$Worker)IO会阻塞在：java.net.SocketInputStream#socketRead0 的native方法上。
通过分析，就可以知道同步调用的一个线程模型：
1.4 总结
优点：
这应该是编程最简单的模型了。调用链非常的清楚，简单直接。不需要其他复杂的机制来解决异步所带来的问题，等着结果即可，所以在很大一部分业务场景中，采用的都是此调用模型。
劣势：
同步阻塞的最大问题在于在调用过程中线程处于等待状态，线程的资源没有充分的利用，对于服务器端应用来说，会限并发的用户数。
本文章为转载内容，我们尊重原作者对文章享有的著作权。如有内容错误或侵权问题，欢迎原作者联系我们进行内容更正或删除文章。
