springboot框架，中间库是mognodb,可以写入2个数据库的Demo

1-springboot版本：
2.3.9.RELEASE
POM.xml文件：

<?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>3.2.1</version>--><version>2.3.9.RELEASE</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.jack</groupId><artifactId>jackDemo</artifactId><version>0.0.1-SNAPSHOT</version><name>jackDemo</name><description>jackDemo</description><properties><java.version>1.8</java.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-mongodb</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-devtools</artifactId><scope>runtime</scope><optional>true</optional></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.75</version></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>

配置文件 application.properties:

server.port=8080
spring.data.mongodb.authentication-database=admin
spring.data.mongodb.database=admin
spring.data.mongodb.username=root
spring.data.mongodb.password=XXXX
#spring.data.mongodb.host=XXX
spring.data.mongodb.host=XXX
spring.data.mongodb.replica-set-name=XXXX
spring.data.mongodb.port=3717
#spring.data.mongodb.uri=XXX# ??????
logging.level.root=INFO
logging.level.org.springframework.web=DEBUG
logging.level.org.hibernate=ERROR# ?????????
logging.file.name=/data/logfile.log# ??????
logging.pattern.console=%d{yyyy-MM-dd HH:mm:ss} - %msg%n
logging.pattern.file=%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n

MongoConfig代码：

package com.jack.XXX.util;import com.mongodb.MongoClientSettings;
import com.mongodb.MongoCredential;
import com.mongodb.ServerAddress;
import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.MongoDatabaseFactory;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory;import java.util.Collections;@Configuration
public class MongoConfig  {@Value("${spring.data.mongodb.authentication-database}")private String authDb;@Value("${spring.data.mongodb.username}")private String username;@Value("${spring.data.mongodb.password}")private String password;@Value("${spring.data.mongodb.host}")private String host;@Value("${spring.data.mongodb.port}")private int port;@Beanpublic MongoClient mongoClient() {MongoCredential credential = MongoCredential.createCredential(username, authDb, password.toCharArray());return MongoClients.create(MongoClientSettings.builder().applyToClusterSettings(builder ->builder.hosts(Collections.singletonList(new ServerAddress(host, port)))).credential(credential).build());}@Beanpublic MongoDatabaseFactory mongoDatabaseFactory(MongoClient mongoClient) {return new SimpleMongoClientDatabaseFactory(mongoClient, authDb);}@Beanpublic MongoTemplate mongoTemplate(MongoDatabaseFactory mongoDatabaseFactory) {return new MongoTemplate(mongoDatabaseFactory);}
}

调用的时候，若使用默认库的就直接

    @Autowiredprivate MongoTemplate mongoTemplate;
mongoTemplate.sve()调用就好。

若是使用别的数据库，则：

 MongoDatabaseFactory factoryForTestDb = new SimpleMongoClientDatabaseFactory(mongoClient, "test");//别的数据库名MongoTemplate mongoTemplateForTestDb = new MongoTemplate(factoryForTestDb);long timestamp = System.currentTimeMillis() - 7 * 24 * 60 * 60 * 1000;Criteria criteria = Criteria.where("timestamp").lt(timestamp);Query query = new Query(criteria);query.limit(300000); // Limit the number of documents returnedList<DeleteCaches> documents = mongoTemplateForTestDb.find(query, DeleteCaches.class); // 使用新的mongoTemplateForTestDb来执行查询Iterator<DeleteCaches> iterator = documents.iterator();while(iterator.hasNext()) {DeleteCaches item = iterator.next();log.warn("待删除的_id:{}",item.getId());mongoTemplateForTestDb.remove(item);}

若mongodb库登录时，要求只能登录认证库admin时，需要修改配置文件application.properties：

server.port=8080
spring.data.mongodb.authentication-database=admin
spring.data.mongodb.uri=mongodb://root:xxX@ip:端口,ip:端口/admin?replicaSet=复制集名称# ??????
logging.level.root=INFO
logging.level.org.springframework.web=DEBUG
logging.level.org.hibernate=ERROR# ?????????
logging.file.name=/data/logfile.log# ??????
logging.pattern.console=%d{yyyy-MM-dd HH:mm:ss} - %msg%n
logging.pattern.file=%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n

MongoConfig代码相应的变更：

import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.MongoDatabaseFactory;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory;@Configuration
public class MongoConfig {@Value("${spring.data.mongodb.uri}")private String uri;@Value("${spring.data.mongodb.authentication-database}")private String authDb;@Beanpublic MongoClient mongoClient() throws Exception {return MongoClients.create(uri);}@Beanpublic MongoDatabaseFactory mongoDatabaseFactory(MongoClient mongoClient) {return new SimpleMongoClientDatabaseFactory(mongoClient, authDb);}@Beanpublic MongoTemplate mongoTemplate(MongoDatabaseFactory mongoDatabaseFactory) {return new MongoTemplate(mongoDatabaseFactory);}
}

MongoDBDeleter 服务类不需要变更