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

spring:
  data:
    mongodb:
      uri: mongodb://localhost/test_mongodb

spring:
  data:
    mongodb:
      authentication-database: # Authentication database name.
      database: # Database name.
      field-naming-strategy: # Fully qualified name of the FieldNamingStrategy to use.
      grid-fs-database: # GridFS database name.
      host: # Mongo server host. Cannot be set with URI.
      password: # Login password of the mongo server. Cannot be set with URI.
      port: # Mongo server port. Cannot be set with URI.
      repositories:
        type: # Type of Mongo repositories to enable.
      uri: # Mongo database URI. Cannot be set with host, port and credentials.
      username: # Login user of the mongo server. Cannot be set with URI.

public class UserEntity {
    @Id
    private String uid;
    private String username;
    private String password;
    public String getUid() {
        return uid;
    }
    public void setUid(String uid) {
        this.uid = uid;
    }
    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;
    }
    @Override
    public String toString() {
        return "UserEntity{" +
                "uid='" + uid + '\'' +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

    @Autowired
    private MongoTemplate mongoTemplate;
    @Test
    public void saveUser(){
        UserEntity userEntity1 = new UserEntity();
        UserEntity userEntity2 = new UserEntity();
        UserEntity userEntity3 = new UserEntity();
        userEntity1.setUid("111");
        userEntity1.setUsername("用戶1");
        userEntity1.setPassword("密碼1");
        userEntity2.setUid("222");
        userEntity2.setUsername("用戶2");
        userEntity2.setPassword("密碼2");
        userEntity3.setUid("333");
        userEntity3.setUsername("用戶3");
        userEntity3.setPassword("密碼3");
        mongoTemplate.save(userEntity1);
        mongoTemplate.save(userEntity2);
        mongoTemplate.save(userEntity3);
    }

    @Autowired
    private MongoTemplate mongoTemplate;
	@Test
    public void findUserByUserName(){
        String username = "用戶1";
        Query query=new Query(Criteria.where("username").is(username));
        UserEntity user =  mongoTemplate.findOne(query , UserEntity.class);
        System.out.println(user);
    }

  @Autowired
    private MongoTemplate mongoTemplate;    
	@Test
    public void updateUser(){
        UserEntity userEntity = new UserEntity();
        userEntity.setUid("111");
        userEntity.setUsername("更新后的用戶名");
        userEntity.setPassword("更新后的密碼");
        Query query = new Query(Criteria.where("_id").is(userEntity.getUid()));
        Update update = Update.update("username",userEntity.getUsername()).set("password",userEntity.getPassword());
        //更新返回結(jié)果集的第一條
        mongoTemplate.updateFirst(query,update,UserEntity.class);
        //更新返回結(jié)果集的所有
        //mongoTemplate.updateMulti(query,update,UserEntity.class);
    }

    @Autowired
    private MongoTemplate mongoTemplate; 
	@Test
    public  void DeleteByUserId(){
        String id = "222";
        Query query=new Query(Criteria.where("_id").is(id));
        mongoTemplate.remove(query,UserEntity.class);
    }