如何通过 JDBC 连接器从我的本地 java 应用程序连接到 AWS RDS

Question

I try to connect to my AWS RDS from my local java application. The error messages are

com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174) ~[mysql-connector-java-8.0.23.jar:8.0.23]
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490) ~[na:na]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:89) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.NativeSession.connect(NativeSession.java:144) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:953) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:823) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    ... 49 common frames omitted
Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:na]
    at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399) ~[na:na]
    at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242) ~[na:na]
    at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224) ~[na:na]
    at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403) ~[na:na]
    at java.base/java.net.Socket.connect(Socket.java:609) ~[na:na]
    at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    ... 52 common frames omitted

2021-05-09 06:42:20.994  INFO 2024 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: default]
2021-05-09 06:42:21.078  INFO 2024 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate ORM core version 5.4.29.Final
2021-05-09 06:42:21.220  INFO 2024 --- [           main] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.1.2.Final}
2021-05-09 06:42:21.326  INFO 2024 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2021-05-09 06:42:22.333 ERROR 2024 --- [           main] com.zaxxer.hikari.pool.HikariPool        : HikariPool-1 - Exception during pool initialization.

com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:833) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:453) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490) ~[na:na]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:89) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.NativeSession.connect(NativeSession.java:144) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:953) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:823) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    ... 50 common frames omitted
Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:na]
    at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399) ~[na:na]
    at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242) ~[na:na]
    at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224) ~[na:na]
    at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403) ~[na:na]
    at java.base/java.net.Socket.connect(Socket.java:609) ~[na:na]
    at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    ... 53 common frames omitted

2021-05-09 06:42:22.336  WARN 2024 --- [           main] o.h.e.j.e.i.JdbcEnvironmentInitiator     : HHH000342: Could not obtain connection to query metadata

com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:833) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:453) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:198) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-3.4.5.jar:na]
    at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:358) ~[HikariCP-3.4.5.jar:na]
    at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-3.4.5.jar:na]
    at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:477) ~[HikariCP-3.4.5.jar:na]
    at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:560) ~[HikariCP-3.4.5.jar:na]
    at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) ~[HikariCP-3.4.5.jar:na]
    at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) ~[HikariCP-3.4.5.jar:na]
    at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcEnvironmentInitiator.java:180) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:68) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:101) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:237) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.injectServices(DefaultIdentifierGeneratorFactory.java:152) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.injectDependencies(AbstractServiceRegistryImpl.java:286) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:243) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.<init>(InFlightMetadataCollectorImpl.java:176) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:127) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:1224) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1255) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) ~[spring-orm-5.3.5.jar:5.3.5]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.3.5.jar:5.3.5]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:409) ~[spring-orm-5.3.5.jar:5.3.5]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:396) ~[spring-orm-5.3.5.jar:5.3.5]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.3.5.jar:5.3.5]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1845) ~[spring-beans-5.3.5.jar:5.3.5]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1782) ~[spring-beans-5.3.5.jar:5.3.5]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:602) ~[spring-beans-5.3.5.jar:5.3.5]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524) ~[spring-beans-5.3.5.jar:5.3.5]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.5.jar:5.3.5]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.5.jar:5.3.5]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.5.jar:5.3.5]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.5.jar:5.3.5]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1154) ~[spring-context-5.3.5.jar:5.3.5]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:908) ~[spring-context-5.3.5.jar:5.3.5]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.5.jar:5.3.5]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:144) ~[spring-boot-2.4.4.jar:2.4.4]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:769) ~[spring-boot-2.4.4.jar:2.4.4]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:761) ~[spring-boot-2.4.4.jar:2.4.4]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:426) ~[spring-boot-2.4.4.jar:2.4.4]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:326) ~[spring-boot-2.4.4.jar:2.4.4]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1313) ~[spring-boot-2.4.4.jar:2.4.4]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1302) ~[spring-boot-2.4.4.jar:2.4.4]
    at team10spring2021cmpe272.petgohome.Backend.PetGoHomeApplication.main(PetGoHomeApplication.java:10) ~[XGP9sau9tY/:na]
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490) ~[na:na]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:89) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.NativeSession.connect(NativeSession.java:144) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:953) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:823) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    ... 50 common frames omitted
Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:na]
    at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399) ~[na:na]
    at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242) ~[na:na]
    at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224) ~[na:na]
    at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403) ~[na:na]
    at java.base/java.net.Socket.connect(Socket.java:609) ~[na:na]
    at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:63) ~[mysql-connector-java-8.0.23.jar:8.0.23]
    ... 53 common frames omitted

2021-05-09 06:42:22.339 ERROR 2024 --- [           main] j.LocalContainerEntityManagerFactoryBean : Failed to initialize JPA EntityManagerFactory: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
2021-05-09 06:42:22.340  WARN 2024 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
2021-05-09 06:42:22.344  INFO 2024 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2021-05-09 06:42:22.363  INFO 2024 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2021-05-09 06:42:22.385 ERROR 2024 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1786) ~[spring-beans-5.3.5.jar:5.3.5]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:602) ~[spring-beans-5.3.5.jar:5.3.5]

al]... 34 common frames omitted

Process finished with exit code 1

I delete some of my error messages because that is too long. Besides, in my java code, I used

  try {
        Class.forName("org.mysql.Driver");
        String jdbcConnString = "jdbc:mysql://my_endpoint_in_aws_rds:3306/my_db_name";
        String jdbcUser = "my_username";
        String jdbcPassword="my_password";

        myConnection = DriverManager.getConnection(jdbcConnString, jdbcUser, jdbcPassword);
  }

I already set my AWS security group inbounds rules to accept all TCP and ICMP-IPv4, which includes my Public IP address, but it still has a communication link failure.

I can use workbench on my local to connect to my AWS RDS with the endpoint, username and password. I have no idea what's the reason, I've tried several methods but still doesn't work. Do I miss something?

Answer 1

You are using mysql. Add the dependency to your pom.xml or graddle.settings

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

Add the values to your application.properties file.

spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect
spring.jpa.hibernate.ddl-auto=update
spring.datasource.hikari.jdbc-url=ADD-TO-HERE-DATABASE-URL
spring.datasource.hikari.username=ADD-TO-HERE-DATABASE-USERNAME
spring.datasource.hikari.password=ADD-TO-HERE-DATABASE-PASSWORD
spring.datasource.hikari.driver-class-name=com.mysql.cj.jdbc.Driver

Then create a class for hikari config.

import com.zaxxer.hikari.HikariDataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;

@Configuration
@ConfigurationProperties(prefix="spring.datasource.hikari")
public class HikariConfig extends com.zaxxer.hikari.HikariConfig {
    @Bean
    public DataSource dataSource() {
        return new HikariDataSource(this);
    }
}

And that's it. I've done a simple project before.You can see an example. click

Also look at these docs.

https://spring.io/guides/gs/accessing-data-mysql/

https://github.com/brettwooldridge/HikariCP