SpringBoot 整合mongoDB并自定义连接池

得力于SpringBoot的特性，整合mongoDB是很容易的，我们整合mongoDB的目的就是想用它给我们提供的mongoTemplate，它可以很容易的操作mongoDB数据库。

为了自定义连接池，我们在配置类中主要与MongoClientOptions、MongoCredential、MongoClient、MongoDbFactory打交道。最终的目的就是配置好一个MongoDbFactory的bean交由Spring管理。

Maven 依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>

配置文件

mongodb:
  database: bfa_mongo
  username: "xxx"
  password: "xxxxx"
  address: "host:port"
  authenticationDatabase: [设置你的认证数据库，如果有的话]
  # 连接池配置
  clientName: ${spring.application.name} # 客户端的标识，用于定位请求来源等
  connectionTimeoutMs: 10000     # TCP连接超时，毫秒
  readTimeoutMs: 15000       # TCP读取超时，毫秒
  poolMaxWaitTimeMs: 3000        #当连接池无可用连接时客户端阻塞等待的时长，单位毫秒
  connectionMaxIdleTimeMs: 60000   #TCP连接闲置时间，单位毫秒
  connectionMaxLifeTimeMs: 120000    #TCP连接最多可以使用多久，单位毫秒
  heartbeatFrequencyMs: 20000      #心跳检测发送频率，单位毫秒
  minHeartbeatFrequencyMs: 8000    #最小的心跳检测发送频率，单位毫秒
  heartbeatConnectionTimeoutMs: 10000  #心跳检测TCP连接超时，单位毫秒
  heartbeatReadTimeoutMs: 15000    #心跳检测TCP连接读取超时，单位毫秒
  connectionsPerHost: 20       # 每个host的TCP连接数
  minConnectionsPerHost: 5     #每个host的最小TCP连接数
  #计算允许多少个线程阻塞等待可用TCP连接时的乘数，算法：threadsAllowedToBlockForConnectionMultiplier*connectionsPerHost，当前配置允许10*20个线程阻塞
  threadsAllowedToBlockForConnectionMultiplier: 10

MongoConfig配置类

配置类中使用了lombok，如果你没有用lombok依赖和IDE插件，你要重写getter、Setter方法：
代码稍长，可以复制在IDEA中查看：

import com.mongodb.MongoClient;
import com.mongodb.MongoClientOptions;
import com.mongodb.MongoCredential;
import com.mongodb.ServerAddress;
import lombok.Getter;
import lombok.Setter;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.mongodb.MongoDbFactory;
import org.springframework.data.mongodb.core.SimpleMongoDbFactory;
import org.springframework.data.mongodb.core.convert.DbRefResolver;
import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
import org.springframework.data.mongodb.core.convert.MongoCustomConversions;
import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
import org.springframework.validation.annotation.Validated;

import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import java.util.ArrayList;
import java.util.List;

@Slf4j
@Configuration
public class MongoConfig {

    /**
     * monogo 转换器
     * @return
     */
    @Bean
    public MappingMongoConverter mappingMongoConverter(MongoDbFactory factory,
                                                       MongoMappingContext context, BeanFactory beanFactory, MongoCustomConversions conversions) {
        DbRefResolver dbRefResolver = new DefaultDbRefResolver(factory);
        MappingMongoConverter mappingConverter = new MappingMongoConverter(dbRefResolver, context);
        // 删除 _class field
//    mappingConverter.setTypeMapper(new DefaultMongoTypeMapper(null));
        mappingConverter.setCustomConversions(conversions);
        return mappingConverter;
    }

    /**
     * 自定义mongo连接池
     * @param properties
     * @return
     */
    @Bean
    public MongoDbFactory mongoDbFactory(MongoClientOptionProperties properties) {
        //创建客户端参数
        MongoClientOptions options = mongoClientOptions(properties);

        //创建客户端和Factory
        List<ServerAddress> serverAddresses = new ArrayList<>();
        for (String address : properties.getAddress()) {
            String[] hostAndPort = address.split(":");
            String host = hostAndPort[0];
            Integer port = Integer.parseInt(hostAndPort[1]);
            ServerAddress serverAddress = new ServerAddress(host, port);
            serverAddresses.add(serverAddress);
        }

        //创建认证客户端
        MongoCredential mongoCredential = MongoCredential.createScramSha1Credential(properties.getUsername(),
                properties.getAuthenticationDatabase() != null ? properties.getAuthenticationDatabase() : properties.getDatabase(),
                properties.getPassword().toCharArray());

        MongoClient mongoClient = new MongoClient(serverAddresses, mongoCredential, options);

        /** ps: 创建非认证客户端*/
        //MongoClient mongoClient = new MongoClient(serverAddresses, mongoClientOptions);
        return new SimpleMongoDbFactory(mongoClient, properties.getDatabase());
    }

    /**
     * mongo客户端参数配置
     * @return
     */
    @Bean
    public MongoClientOptions mongoClientOptions(MongoClientOptionProperties properties) {
        return MongoClientOptions.builder()
                .connectTimeout(properties.getConnectionTimeoutMs())
                .socketTimeout(properties.getReadTimeoutMs()).applicationName(properties.getClientName())
                .heartbeatConnectTimeout(properties.getHeartbeatConnectionTimeoutMs())
                .heartbeatSocketTimeout(properties.getHeartbeatReadTimeoutMs())
                .heartbeatFrequency(properties.getHeartbeatFrequencyMs())
                .minHeartbeatFrequency(properties.getMinHeartbeatFrequencyMs())
                .maxConnectionIdleTime(properties.getConnectionMaxIdleTimeMs())
                .maxConnectionLifeTime(properties.getConnectionMaxLifeTimeMs())
                .maxWaitTime(properties.getPoolMaxWaitTimeMs())
                .connectionsPerHost(properties.getConnectionsPerHost())
                .threadsAllowedToBlockForConnectionMultiplier(
                        properties.getThreadsAllowedToBlockForConnectionMultiplier())
                .minConnectionsPerHost(properties.getMinConnectionsPerHost()).build();
    }

    @Primary
    @Bean
    @ConfigurationProperties(prefix = "mongodb")
    public MongoClientOptionProperties mongoClientOptionProperties() {
        return new MongoClientOptionProperties();
    }

    @Getter
    @Setter
    @Validated
    @Configuration
    public static class MongoClientOptionProperties {

        /** 基础连接参数 */
        private String database;
        private String username;
        private String password;
        @NotNull
        private List<String> address;
        private String authenticationDatabase;

        /** 客户端连接池参数 */
        @NotNull
        @Size(min = 1)
        private String clientName;
        /** socket连接超时时间 */
        @Min(value = 1)
        private int connectionTimeoutMs;
        /** socket读取超时时间 */
        @Min(value = 1)
        private int readTimeoutMs;
        /** 连接池获取链接等待时间 */
        @Min(value = 1)
        private int poolMaxWaitTimeMs;
        /** 连接闲置时间 */
        @Min(value = 1)
        private int connectionMaxIdleTimeMs;
        /** 连接最多可以使用多久 */
        @Min(value = 1)
        private int connectionMaxLifeTimeMs;
        /** 心跳检测发送频率 */
        @Min(value = 2000)
        private int heartbeatFrequencyMs;

        /** 最小的心跳检测发送频率 */
        @Min(value = 300)
        private int minHeartbeatFrequencyMs;
        /** 计算允许多少个线程阻塞等待时的乘数，算法：threadsAllowedToBlockForConnectionMultiplier*connectionsPerHost */
        @Min(value = 1)
        private int threadsAllowedToBlockForConnectionMultiplier;
        /** 心跳检测连接超时时间 */
        @Min(value = 200)
        private int heartbeatConnectionTimeoutMs;
        /** 心跳检测读取超时时间 */
        @Min(value = 200)
        private int heartbeatReadTimeoutMs;

        /** 每个host最大连接数 */
        @Min(value = 1)
        private int connectionsPerHost;
        /** 每个host的最小连接数 */
        @Min(value = 1)
        private int minConnectionsPerHost;
    }
}

MappingMongoConverter可以自定义mongo转换器，主要自定义存取mongo数据时的一些操作，例如 mappingConverter.setTypeMapper(new DefaultMongoTypeMapper(null)) 方法会将mongo数据中的_class字段去掉。

最后通过 new SimpleMongoDbFactory(mongoClient, properties.getDatabase())方法配置了一个MongoDbFactory交由Spring管理，Springboot会拿这个MongoDbFactory工厂bean来new一个MongoTemplate，在MongoDbFactoryDependentConfiguration类下可以看到SpringBoot帮你做得事：

/**
 * Configuration for Mongo-related beans that depend on a {@link MongoDbFactory}.
 *
 * @author Andy Wilkinson
 */
@Configuration
@ConditionalOnBean(MongoDbFactory.class)
class MongoDbFactoryDependentConfiguration {

    private final MongoProperties properties;

    MongoDbFactoryDependentConfiguration(MongoProperties properties) {
        this.properties = properties;
    }
    
    //SpringBoot创建MongoTemplate实例
    @Bean
    @ConditionalOnMissingBean
    public MongoTemplate mongoTemplate(MongoDbFactory mongoDbFactory, MongoConverter converter) {
        return new MongoTemplate(mongoDbFactory, converter);
    }

    @Bean
    @ConditionalOnMissingBean(MongoConverter.class)
    public MappingMongoConverter mappingMongoConverter(MongoDbFactory factory, MongoMappingContext context,
            MongoCustomConversions conversions) {
        DbRefResolver dbRefResolver = new DefaultDbRefResolver(factory);
        MappingMongoConverter mappingConverter = new MappingMongoConverter(dbRefResolver, context);
        mappingConverter.setCustomConversions(conversions);
        return mappingConverter;
    }
    
    //...
}

SpringBoot利用我们配置好的MongoDbFactory在配置类中生成一个MongoTemplate，之后我们就可以在项目代码中直接@Autowired了。因为用于生成MongoTemplate的MongoDbFactory是我们自己在MongoConfig配置类中生成的，所以我们自定义的连接池参数也就生效了。