First, there is no connection pool configuration

server:
  port: 4567

spring:
  datasource:
    username: postgres
    password: 123456
    url: jdbc:postgresql://localhost:5432/myjpaproject
    driver-class-name: org.postgresql.Driver
  jpa:
         Database-platform: org.hibernate.dialect.PostgreSQL95Dialect #Set dialect
    properties:
      hibernate:
                 Jdbc.lob.non_contextual_creation: true # Prevent the postgresql database from checking for data errors caused by not implementing CLOB format

Or multi-environment configuration (only the development environment is added here), test and production environment can be added later

server:
  port: 4567

spring:
  profiles:
             Active: dev #default active profiles
  jpa:
         Database-platform: org.hibernate.dialect.PostgreSQL95Dialect #Set dialect
    properties:
      hibernate:
                 Jdbc.lob.non_contextual_creation: true # Prevent the postgresql database from checking for data errors caused by not implementing CLOB format


---
spring:
  profiles: dev
  datasource:
    driver-class-name: org.postgresql.Driver
    url: jdbc:postgresql://localhost:5432/myjpaproject
    username: postgres
    password: 123456

Second, there is a connection pool configuration

Add package to build.gradle

// druid database connection pool
implementation 'com.alibaba:druid-spring-boot-starter:1.1.10'

Configuration:

server:
  port: 4567

spring:
  datasource:
    druid:
      db-type: com.alibaba.druid.pool.DruidDataSource
      driver-class-name: org.postgresql.Driver
      url: jdbc:postgresql://localhost:5432/myjpaproject
      username: postgres
      password: 123456
      Filters: stat #alias mode, extension plugin, filter for monitoring statistics: stat, filter for log: log4j, sql injection filter: wall

or

server:
  port: 4567

spring:
  profiles:
             Active: dev #default active profiles
  jpa:
         Database-platform: org.hibernate.dialect.PostgreSQL95Dialect #Set dialect
    properties:
      hibernate:
                 Jdbc.lob.non_contextual_creation: true # Prevent the postgresql database from checking for data errors caused by not implementing CLOB format


---
spring:
  profiles: dev
  datasource:
    druid:
      db-type: com.alibaba.druid.pool.DruidDataSource
      driver-class-name: org.postgresql.Driver
      url: jdbc:postgresql://localhost:5432/myjpaproject
      username: postgres
      password: 123456
             Filters: stat #alias mode, extension plugin, filter for monitoring statistics: stat, filter for log: log4j, sql injection filter: wall

All driud configuration:

db-type: com.alibaba.druid.pool.DruidDataSource
      driver-class-name: org.postgresql.Driver
      url: jdbc:postgresql://localhost:5432/myjpaproject
      username: postgres
      password: 123456
             # The following is a supplementary setting for the connection pool, applied to all the above data sources
             # Initialize size, minimum, maximum
      initialSize: 1
      minIdle: 3
      maxActive: 20
             # Configure the timeout for waiting for the connection to wait.
      maxWait: 60000
             # Configure the interval to detect once, and detect the idle connection that needs to be closed. The unit is milliseconds.
      timeBetweenEvictionRunsMillis: 60000
             # Configure the minimum lifetime of a connection in the pool, in milliseconds
      minEvictableIdleTimeMillis: 30000
      validationQuery: select 'x'
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
             # Open PSCache and specify the size of PSCache on each connection.
      poolPreparedStatements: true
      maxPoolPreparedStatementPerConnectionSize: 20
             # Configure monitoring statistics interception filters, remove the monitoring interface sql can not be counted, 'wall' for firewall, #alias mode, extension plug-in, monitor statistics filter: stat, log filter: log4j, defense sql injection filter :wall
      filters: stat,slf4j
             # Open the mergeSql function via the connectProperties property; slow SQL logging
      connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000