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使用LettuceConnectionFactory

分类：编程问答

如何解决使用LettuceConnectionFactory

我正在尝试使用反应式Spring Boot创建一个非阻塞api，该API可以存储和检索来自Redis集群的简单消息。一个非常简单的应用程序。我正在将 spring-boot-starter-data-redis-reactive 依赖性用于反应式Redis客户端，并将 blockhound 用于检测阻塞调用。最初，我的应用程序运行正常，但是当我尝试安装Blockhound来检测阻塞调用时，它会引发异常。

这是我的 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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.tigerit.example</groupId>
    <artifactId>reactivespring</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>reactivespring</name>
    <description>Demo project for Reactive Spring Boot</description>

    <properties>
        <java.version>11</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis-reactive</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-rsocket</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>

        <dependency>
            <groupId>io.projectreactor.tools</groupId>
            <artifactId>blockhound</artifactId>
            <version>1.0.4.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>io.projectreactor</groupId>
            <artifactId>reactor-tools</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>io.projectreactor</groupId>
            <artifactId>reactor-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>

这是我的bean配置类 RedisConfiguration ：

package com.tigerit.example.reactivespring.configuration;

import com.tigerit.example.reactivespring.model.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.redis.connection.ReactiveRedisConnectionFactory;
import org.springframework.data.redis.connection.RedisClusterConfiguration;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.core.ReactiveRedistemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.StringRedisSerializer;

import java.util.List;


@Configuration
public class RedisConfiguration {

    @Value("${spring.redis.cluster.nodes}")
    private List<String> redisClusterNodes;

    @Bean
    public RedisClusterConfiguration getRedisClusterConfiguration() {
        return new RedisClusterConfiguration(this.redisClusterNodes);
    }

    @Bean
    @Primary
    public ReactiveRedisConnectionFactory getReactiveRedisConnectionFactory(@Autowired RedisClusterConfiguration configuration) {
        return new LettuceConnectionFactory(configuration);
    }

    @Bean
    @Primary
    public ReactiveRedistemplate<String,User> getReactiveRedistemplate(@Autowired ReactiveRedisConnectionFactory factory) {
        StringRedisSerializer keySerializer = new StringRedisSerializer();
        Jackson2JsonRedisSerializer<User> valueSerializer = new Jackson2JsonRedisSerializer<>(User.class);
        RedisSerializationContext.RedisSerializationContextBuilder<String,User> contextBuilder =
                RedisSerializationContext.newSerializationContext(keySerializer);
        RedisSerializationContext<String,User> context = contextBuilder.value(valueSerializer).build();
        return new ReactiveRedistemplate<>(factory,context);
    }
}

这是我的休息控制器类 UserController ：

package com.tigerit.example.reactivespring.restcontroller;

import com.tigerit.example.reactivespring.model.User;
import lombok.requiredArgsConstructor;
import lombok.extern.log4j.Log4j2;
import org.springframework.data.redis.core.ReactiveRedistemplate;
import org.springframework.data.redis.core.ReactiveValueOperations;
import org.springframework.web.bind.annotation.*;
import reactor.core.publisher.Mono;

@RestController
@RequestMapping("/rest/user")
@requiredArgsConstructor
@Log4j2
public class UserController {

    private final ReactiveRedistemplate<String,User> redistemplate;

    @PostMapping("/add")
    public Mono<Boolean> saveUser(@RequestParam(value = "message",defaultValue = "EMPTY_MESSAGE") String message) {
        User user = new User(System.currentTimeMillis(),message);
        log.info(user);
        ReactiveValueOperations<String,User> operations = this.redistemplate.opsForValue();
        return operations.set(user.getId().toString(),user);
    }

    @GetMapping("/{id}")
    public Mono<User> getById(@PathVariable(value = "id",required = true) String id) {
        ReactiveValueOperations<String,User> operations = this.redistemplate.opsForValue();
        return operations.get(id);
    }
}

这是我的主要课程主要：

package com.tigerit.example.reactivespring;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import reactor.blockhound.BlockHound;

@SpringBootApplication
public class Main {

    public static void main(String[] args) {
        BlockHound.install();
        SpringApplication.run(Main.class,args);
    }

}

注意：当我在不安装Blockhound的情况下运行此应用程序时，它可以工作，但是当我尝试在Main中安装Blockhound时，它将引发以下异常。 

reactor.blockhound.BlockingOperationError: Blocking call! jdk.internal.misc.Unsafe#park
    at java.base/jdk.internal.misc.Unsafe.park(Unsafe.java) ~[na:na]
    Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Assembly trace from producer [reactor.core.publisher.FluxUsingWhen] :
    reactor.core.publisher.Flux.usingWhen
    org.springframework.data.redis.core.ReactiveRedistemplate.doInConnection(ReactiveRedistemplate.java:195)
Error has been observed at the following site(s):
    |_     Flux.usingWhen ⇢ at org.springframework.data.redis.core.ReactiveRedistemplate.doInConnection(ReactiveRedistemplate.java:195)
    |_          Mono.from ⇢ at org.springframework.data.redis.core.ReactiveRedistemplate.createMono(ReactiveRedistemplate.java:179)
    |_                    ⇢ at org.springframework.data.redis.core.DefaultReactiveValueOperations.createMono(DefaultReactiveValueOperations.java:349)
    |_                    ⇢ at org.springframework.data.redis.core.DefaultReactiveValueOperations.get(DefaultReactiveValueOperations.java:171)
    |_                    ⇢ at com.tigerit.example.reactivespring.restcontroller.UserController.getById(UserController.java:31)
    |_          Mono.from ⇢ at org.springframework.http.codec.json.AbstractJackson2Encoder.encode(AbstractJackson2Encoder.java:136)
    |_           Mono.map ⇢ at org.springframework.http.codec.json.AbstractJackson2Encoder.encode(AbstractJackson2Encoder.java:137)
    |_          Mono.flux ⇢ at org.springframework.http.codec.json.AbstractJackson2Encoder.encode(AbstractJackson2Encoder.java:138)
    |_ Flux.singleOrEmpty ⇢ at org.springframework.http.codec.EncoderHttpMessageWriter.write(EncoderHttpMessageWriter.java:122)
    |_ Mono.switchIfEmpty ⇢ at org.springframework.http.codec.EncoderHttpMessageWriter.write(EncoderHttpMessageWriter.java:123)
    |_       Mono.flatMap ⇢ at org.springframework.http.codec.EncoderHttpMessageWriter.write(EncoderHttpMessageWriter.java:127)
    |_                    ⇢ at org.springframework.http.codec.EncoderHttpMessageWriter.write(EncoderHttpMessageWriter.java:203)
    |_                    ⇢ at org.springframework.web.reactive.result.method.annotation.AbstractMessageWriterResultHandler.writeBody(AbstractMessageWriterResultHandler.java:107)
    |_                    ⇢ at org.springframework.web.reactive.result.method.annotation.ResponseBodyResultHandler.handleResult(ResponseBodyResultHandler.java:86)
    |_         checkpoint ⇢ Handler com.tigerit.example.reactivespring.restcontroller.UserController#getById(String) [dispatcherHandler]
    |_                    ⇢ at org.springframework.web.server.handler.DefaultWebFilterChain.lambda$filter$0(DefaultWebFilterChain.java:120)
    |_         Mono.defer ⇢ at org.springframework.web.server.handler.DefaultWebFilterChain.filter(DefaultWebFilterChain.java:119)
    |_                    ⇢ at org.springframework.web.server.handler.FilteringWebHandler.handle(FilteringWebHandler.java:59)
    |_                    ⇢ at org.springframework.web.server.handler.WebHandlerDecorator.handle(WebHandlerDecorator.java:56)
    |_         Mono.error ⇢ at org.springframework.web.server.handler.ExceptionHandlingWebHandler$CheckpointInsertingHandler.handle(ExceptionHandlingWebHandler.java:98)
    |_         checkpoint ⇢ HTTP GET "/rest/user/add" [ExceptionHandlingWebHandler]
    |_                    ⇢ at org.springframework.web.server.handler.ExceptionHandlingWebHandler.lambda$handle$0(ExceptionHandlingWebHandler.java:77)
    |_ Mono.onErrorResume ⇢ at org.springframework.web.server.handler.ExceptionHandlingWebHandler.handle(ExceptionHandlingWebHandler.java:77)

解决方法

请尝试这个。这是全面解决方案。 ：D 

@AutoService(BlockHoundIntegration.class)
public class BlockHoundConfig implements BlockHoundIntegration {

    @Override
    public void applyTo(BlockHound.Builder builder) {
        builder.allowBlockingCallsInside("io.lettuce.core.protocol.RedisHandshakeHandler","channelRegistered");
    }
}

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