Spring Boot中使用MongoDB的连接池配置

因为今天开发遇到了性能问题，可能与MongoDB的连接有关，所以稍稍深入看了一下，正好搜到原来有人写过这篇相关的内容，所以转载过来。回头有时间可以写个扩展到SpringForAll里，主体思路还是一样的。感谢这位美女程序媛的文章！

说明

Spring Boot中通过依赖spring-boot-starter-data-mongodb，来实现spring-data-mongodb的自动配置。
但是默认情况下，Spring Boot 中，并没有像使用MySQL或者Redis一样，提供了连接池配置的功能。因此，我们需要自行重写 MongoDbFactory，实现MongoDB客户端连接的参数配置扩展。

需要说明的是，MongoDB的客户端本身就是一个连接池，因此，我们只需要配置客户端即可。

配置文件

为了统一Spring Boot的配置，我们要将重写的配置也配置到 application.yml中，前缀为spring.data.mongodb.custom下（前缀可自己随意配置）：

spring:
 data:
 mongodb:
 custom:
 hosts:
 - 10.0.5.1
 - 10.0.5.1
 ports:
 - 27017
 - 27018
 replica-set: mgset-3590061
 username: jancee
 password: abc123
 database: jancee
 authentication-database: admin
 connections-per-host: 20
 min-connections-per-host: 20

该配置例子中，配置了副本集，其中包含了主机10.0.5.1:27017和10.0.5.1:27018，其它配置与Spring Boot的标准配置类似，另外，connections-per-host为客户端的连接数，in-connections-per-host为客户端最小连接数。

将配置包装成类

为方便调用和可读性，将上述配置包装成一个配置实体类，MongoConfig.java代码如下:

package com.feidiao.jancee.fdiot.api.config.mongo;

import org.hibernate.validator.constraints.NotBlank;
import org.hibernate.validator.constraints.NotEmpty;
import org.springframework.stereotype.Component;
import org.springframework.validation.annotation.Validated;

import java.util.List;

@Component
@Validated
public class MongoSettingsProperties {

    @NotBlank
    private String database;

    @NotEmpty
    private List<String> hosts;

    @NotEmpty
    private List<Integer> ports;

    private String replicaSet;
    private String username;
    private String password;
    private String authenticationDatabase;
    private Integer minConnectionsPerHost = 10;
    private Integer connectionsPerHost = 2;

    public MongoSettingsProperties() {

    }

    public String getDatabase() {
        return database;
    }

    public void setDatabase(String database) {
        this.database = database;
    }

    public List<String> getHosts() {
        return hosts;
    }

    public void setHosts(List<String> hosts) {
        this.hosts = hosts;
    }

    public List<Integer> getPorts() {
        return ports;
    }

    public void setPorts(List<Integer> ports) {
        this.ports = ports;
    }

    public String getReplicaSet() {
        return replicaSet;
    }

    public void setReplicaSet(String replicaSet) {
        this.replicaSet = replicaSet;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getAuthenticationDatabase() {
        return authenticationDatabase;
    }

    public void setAuthenticationDatabase(String authenticationDatabase) {
        this.authenticationDatabase = authenticationDatabase;
    }

    public Integer getMinConnectionsPerHost() {
        return minConnectionsPerHost;
    }

    public void setMinConnectionsPerHost(Integer minConnectionsPerHost) {
        this.minConnectionsPerHost = minConnectionsPerHost;
    }

    public Integer getConnectionsPerHost() {
        return connectionsPerHost;
    }

    public void setConnectionsPerHost(Integer connectionsPerHost) {
        this.connectionsPerHost = connectionsPerHost;
    }
}

覆盖MongoDbFactory

接下来，就是覆盖Spring Boot原有的MongoDbFactory Bean，新建文件MongoConfig.java，代码如下：

import com.mongodb.MongoClient;
import com.mongodb.MongoClientOptions;
import com.mongodb.MongoCredential;
import com.mongodb.ServerAddress;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.MongoDbFactory;
import org.springframework.data.mongodb.core.SimpleMongoDbFactory;

import java.util.ArrayList;
import java.util.List;

@Configuration
public class MongoConfig {


    // 注入配置实体
    @Autowired
    private MongoSettingsProperties mongoSettingsProperties;
    @Bean
    @ConfigurationProperties(
            prefix = "spring.data.mongodb.custom")
    MongoSettingsProperties mongoSettingsProperties() {
        return new MongoSettingsProperties();
    }

    // 覆盖默认的MongoDbFactory
    @Bean
    MongoDbFactory mongoDbFactory() {
        //客户端配置（连接数、副本集群验证）
        MongoClientOptions.Builder builder = new MongoClientOptions.Builder();
        builder.connectionsPerHost(mongoSettingsProperties.getConnectionsPerHost());
        builder.minConnectionsPerHost(mongoSettingsProperties.getMinConnectionsPerHost());
        if (mongoSettingsProperties.getReplicaSet() != null) {
            builder.requiredReplicaSetName(mongoSettingsProperties.getReplicaSet());
        }
        MongoClientOptions mongoClientOptions = builder.build();

        // MongoDB地址列表
        List<ServerAddress> serverAddresses = new ArrayList<>();
        for (String host : mongoSettingsProperties.getHosts()) {
            Integer index = mongoSettingsProperties.getHosts().indexOf(host);
            Integer port = mongoSettingsProperties.getPorts().get(index);

            ServerAddress serverAddress = new ServerAddress(host, port);
            serverAddresses.add(serverAddress);
        }
        System.out.println("serverAddresses:" + serverAddresses.toString());

        // 连接认证
        List<MongoCredential> mongoCredentialList = new ArrayList<>();
        if (mongoSettingsProperties.getUsername() != null) {
            mongoCredentialList.add(MongoCredential.createScramSha1Credential(
                    mongoSettingsProperties.getUsername(),
                    mongoSettingsProperties.getAuthenticationDatabase() != null ? mongoSettingsProperties.getAuthenticationDatabase() : mongoSettingsProperties.getDatabase(),
                    mongoSettingsProperties.getPassword().toCharArray()));
        }
        System.out.println("mongoCredentialList:" + mongoCredentialList.toString());

        //创建客户端和Factory
        MongoClient mongoClient = new MongoClient(serverAddresses, mongoCredentialList, mongoClientOptions);
        MongoDbFactory mongoDbFactory = new SimpleMongoDbFactory(mongoClient, mongoSettingsProperties.getDatabase());

        return mongoDbFactory;
    }
}