Mongodb学习笔记--springboot中使用mongodb

# MongoDB springboot集成mongoDB的使用
在springboot中对mongodb和redis等NoSql数据库都已经有集成了,这里主要学习如何去使用springboot框架集成的mongodb。  
首先导入依赖:
```xml
<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-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
</dependencies>
```
打开mongodb副本集，创建study数据库，并为数据库创建用户名密码。
在springboot的配置文件中添加mongodb的配置：
```properties
#单节点配置
#spring.data.mongodb.uri=mongodb://user:pwd@ip:port/database
#集群配置
spring.data.mongodb.uri=mongodb://root:123456@192.168.226.130:27017,192.168.226.130:27018,192.168.226.130:27019/study
```
mongodb的增删改查：
+ 创建实体类book
```java
@Data
@Accessors(chain = true)
public class Book implements Serializable {

    private static final long serialVersionUID = 1L;

    private Long id;
    private String name;
    private String content;
    private BigDecimal price;
}
```
+ 创建mongoService接口：
```java
public interface MongoService<T> {

    void save(T t);

    void delete(Long id);

    Long update(T t);

    T queryForOne(T t);
}
```
+ 实现接口：
```java
@Service
@Slf4j
public class MongoServiceImpl implements MongoService<Book> {

    @Autowired
    private MongoTemplate mongoTemplate;

    @Override
    public void save(Book book) {
        log.debug("要保存的对象[{}]", book.toString());
        mongoTemplate.save(book);
    }

    @Override
    public void delete(Long id) {
        log.debug("要删除的对象id:[{}]", id);
        Query query = new Query(Criteria.where("id").is(id));
        mongoTemplate.remove(query, Book.class);
    }

    @Override
    public Long update(Book book) {
        Query query = new Query(Criteria.where("id").is(book.getId()));
        Update update = new Update().set("name", book.getName()).set("price", book.getPrice()).set("content", book.getContent());
        UpdateResult result = mongoTemplate.updateFirst(query, update, Book.class);

        return Objects.isNull(result) ? 0 : result.getMatchedCount();
    }

    @Override
    public Book queryForOne(Book book) {
        Query query = new Query(Criteria.where("name").is(book.getName()));
        return mongoTemplate.findOne(query, Book.class);
    }
}
```
+ 测试：
```
    @Test
    void test() {
        mongoService.save(new Book().setId(1L).setName("java").setPrice(BigDecimal.valueOf(50.55)).setContent("hello java"));
        mongoService.save(new Book().setId(2L).setName("c").setPrice(BigDecimal.valueOf(55.55)).setContent("hello c"));
        mongoService.update(new Book().setId(1L).setName("python").setContent("hello python").setPrice(BigDecimal.valueOf(60.01)));
        Book book = mongoService.queryForOne(new Book().setName("python"));
        System.out.println(book.toString());
        mongoService.delete(1L);

    }
```
mongodb增删改查实现完成。
可以在mongodb中使用shell命令查看数据是否正确。
```shell script
rs0:PRIMARY> use study
switched to db study
rs0:PRIMARY> db.auth("root","123456")
1
rs0:PRIMARY> show collections
book
system.indexes
rs0:PRIMARY> db.book.find()
{ "_id" : NumberLong(2), "name" : "c", "content" : "hello c", "price" : "55.55", "_class" : "com.xiazhi.mongodb.bean.Book" }
```