1.maven的pom.xml中引入jar包:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>
2.application.properties中配置mongodb地址:
## mongodb ##
spring.data.mongodb.uri=mongodb://127.0.0.1:27017/test
若连接需要账号验证,改为:
spring.data.mongodb.uri=mongodb://root:[email protected]:27017/test
3.使用
3.1在使用类中直接注入
@Autowired
MongoTemplate mongoTemplate;
3.2聚合
String alias = "nowNum";
Aggregation aggregation = Aggregation.newAggregation(
Aggregation.match(Criteria.where("name").is(name)),
Aggregation.group("age").count().as(alias)
);
AggregationResults<Map> results= mongoTemplate.aggregate(aggregation, "testCollection", Map.class);
List<Map> mappedResults = results.getMappedResults();
if (mappedResults != null && mappedResults.size() > 0) {
Integer num = (Integer) mappedResults.get(0).get(alias);
return num;
}
3.3多条件聚合查询
String alias = "nowNum";
Aggregation aggregation = Aggregation.newAggregation(
Aggregation.match(Criteria.where("name").is(name).and("size").is(size)),
//Aggregation.match(Criteria.where("size").is(size)),
Aggregation.group("age").count().as(alias)
);
AggregationResults<Map> results= mongoTemplate.aggregate(aggregation, "testCollection", Map.class);
List<Map> mappedResults = results.getMappedResults();
if (mappedResults != null && mappedResults.size() > 0) {
Integer num = (Integer) mappedResults.get(0).get(alias);
return num;
}
3.4分页查询
Query query = new Query(Criteria.where("name").is(name).and("size").is(size).and("age").is(age))
.skip((page.getPageNum()-1)*page.getPageSize())
.limit(page.getPageSize());
List<JavaEntity> list= mongoTemplate.find(query, JavaEntity.class, "testCollection");
long totalSize = mongoTemplate.count(query, JavaEntity.class, "testCollection");
page.setTotalSize((int) totalSize);
注意:分页查询是最基本的查询,看网上说法,这种查询会导致mongodb的全表查询,即整个collection的查询,所以collection的数据量大的时候不建议使用这种方式,具体可百度mongodb的分页优化,暂时自己没有亲测。