非常简单的设置:
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>demo-rest-client</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>demo-rest-client</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.5.Final</version>
</dependency>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-buffer</artifactId>
<version>4.1.5.Final</version>
</dependency>
<dependency>
<groupId>com.squareup.okhttp3</groupId>
<artifactId>okhttp</artifactId>
<version>3.4.1</version>
</dependency>
<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-core</artifactId>
<version>9.3.1</version>
</dependency>
<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-hystrix</artifactId>
<version>9.3.1</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
以及演示 AsyncRestTemplate 不同用法的测试用例:
SampleTests.java
package com.example;
import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommandProperties;
import feign.RequestLine;
import feign.hystrix.HystrixFeign;
import feign.hystrix.SetterFactory;
import org.junit.Test;
import org.springframework.http.ResponseEntity;
import org.springframework.http.client.Netty4ClientHttpRequestFactory;
import org.springframework.http.client.OkHttp3ClientHttpRequestFactory;
import org.springframework.util.concurrent.ListenableFuture;
import org.springframework.web.client.AsyncRestTemplate;
import org.springframework.web.client.RestTemplate;
public class SampleTests {
private static final String URL = "https://api.github.com/users/octocat";
private static final int DEFAULT_SLEEP_MILLIS = 20;
private static final int DEFAULT_TIMEOUT = 10000;
@Test(timeout = DEFAULT_TIMEOUT)
public void syncRestNetty() throws Exception {
RestTemplate restTemplate = new RestTemplate(new Netty4ClientHttpRequestFactory());
ResponseEntity<String> response = restTemplate.getForEntity(URL, String.class);
System.out.println("response = " + response);
}
@Test(timeout = DEFAULT_TIMEOUT)
public void asyncRestNetty() throws Exception {
AsyncRestTemplate restTemplate = new AsyncRestTemplate(new Netty4ClientHttpRequestFactory());
ListenableFuture<ResponseEntity<String>> listenableFuture = restTemplate.getForEntity(URL, String.class);
listenableFuture.addCallback(result -> System.out.println("result = " + result), Throwable::printStackTrace);
while (!listenableFuture.isDone()) {
Thread.sleep(DEFAULT_SLEEP_MILLIS);
}
System.out.println("the end");
}
@Test
public void asyncRestOkHttp() throws Exception {
AsyncRestTemplate restTemplate = new AsyncRestTemplate(new OkHttp3ClientHttpRequestFactory());
ListenableFuture<ResponseEntity<String>> listenableFuture = restTemplate.getForEntity(URL, String.class);
listenableFuture.addCallback(result -> System.out.println("result = " + result), Throwable::printStackTrace);
while (!listenableFuture.isDone()) {
Thread.sleep(DEFAULT_SLEEP_MILLIS);
}
System.out.println("the end");
}
@Test
public void asyncRestHystrixFeign() throws Exception {
GitHub gitHub = HystrixFeign.builder()
.setterFactory((target, method) -> new SetterFactory.Default().create(target, method).andCommandPropertiesDefaults(HystrixCommandProperties.defaultSetter().withExecutionTimeoutInMilliseconds(10000)))
.target(GitHub.class, "https://api.github.com");
HystrixCommand<String> command = gitHub.octocatAsync();
command.toObservable().subscribe(result -> System.out.println("result = " + result), Throwable::printStackTrace);
while (!command.isExecutionComplete()) {
Thread.sleep(DEFAULT_SLEEP_MILLIS);
}
System.out.println("command.getExecutionTimeInMilliseconds() = " + command.getExecutionTimeInMilliseconds());
System.out.println("the end");
}
interface GitHub {
@RequestLine("GET /users/octocat")
HystrixCommand<String> octocatAsync();
}
}
当尝试运行使用 Netty 的测试时，它们会永远挂起。 (要查看此内容，请删除 JUnit 超时约束)。但是，如果我与其他客户端运行完全相同的代码，一切都会按预期进行。
我试过不同版本的Spring Boot和Netty都没有成功。从日志来看，一切正常。
我在这里错过了什么？
编辑: 开了工单https://jira.spring.io/browse/SPR-14744正如 Spring Gitter 上所建议的那样
编辑-2: Brian Clozel 的回答帮助我找到了与 Netty 相关的问题，没有意识到服务器发送了一个空响应(Github API 和纯 http 的特殊情况)所以我将其标记为已接受。
最佳答案
您可以尝试使用 Netty Sslcontext 配置您的请求工厂吗？
Netty4ClientHttpRequestFactory nettyFactory = new Netty4ClientHttpRequestFactory();
nettyFactory.setSslContext(SslContextBuilder.forClient().build());
AsyncRestTemplate restTemplate = new AsyncRestTemplate(nettyFactory);
如果没有该上下文，客户端将尝试向 https 端点发送明文请求；在这种情况下，您可能会收到 HTTP 400 响应。
在您的示例代码中，throwable 应该是 HttpClientErrorException 的一个实例，您可以通过记录响应状态或其包含 exception 的正文来获取该信息.getResponseBodyAsString().
关于java - 带有 Netty4 的 Spring RestTemplate 和 AsyncRestTemplate 永远挂起，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/39639467/