Tomcat服务器中的SpringBoot应用程序：找不到PostgreSQL驱动程序

Question

我正在使用Spring启动应用程序使用Eclipse IDE开发基于Postgresql的应用程序（openjdk版本1.8.0_151）

我已按如下方式配置gradle：

compile group: 'org.postgresql', name: 'postgresql', version: '42.1.4'      
compile group: 'org.springframework.boot', name: 'spring-boot-starter-jdbc'

我使用Spring JdbcTemplate来访问数据库。在Eclipse IDE中，一切都很完美。我想创建一个war文件并部署到Tomcat 9服务器中。但不幸的是，我收到以下错误消息：

org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: No suitable driver found for jdbc:postgresql://server:5432/db_pm
    at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80)
    at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:619)
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:684)
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:716)
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:726)
    at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:776)
    at org.springframework.jdbc.core.JdbcTemplate.queryForList(JdbcTemplate.java:853)
    at com.kpaudel.pm.PasswordManagerDAO.getSimilarServices(PasswordManagerDAO.java:108)
    at com.kpaudel.pm.PasswordManagerDAO$$FastClassBySpringCGLIB$$482fbdc8.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:738)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:673)
    at com.kpaudel.pm.PasswordManagerDAO$$EnhancerBySpringCGLIB$$8f3e1618.getSimilarServices(<generated>)
    at com.kpaudel.telegram.bots.PasswordManagerBot.onUpdateReceived(PasswordManagerBot.java:87)
    at java.util.ArrayList.forEach(ArrayList.java:1255)
    at org.telegram.telegrambots.generics.LongPollingBot.onUpdatesReceived(LongPollingBot.java:27)
    at org.telegram.telegrambots.updatesreceivers.DefaultBotSession$HandlerThread.run(DefaultBotSession.java:301)
Caused by: java.sql.SQLException: No suitable driver found for jdbc:postgresql://server:5432/db_pm
    at java.sql.DriverManager.getConnection(DriverManager.java:689)
    at java.sql.DriverManager.getConnection(DriverManager.java:208)
    at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriverManager(DriverManagerDataSource.java:153)
    at org.springframework.jdbc.datasource.DriverManagerDataSource.getConnectionFromDriver(DriverManagerDataSource.java:144)
    at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnectionFromDriver(AbstractDriverBasedDataSource.java:196)
    at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnection(AbstractDriverBasedDataSource.java:159)
    at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111)
    at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
    ... 19 common frames omitted

我已将Postgresql驱动程序（postgresql-42.1.4.jar）复制到$ CATALINA_HOME / lib目录中，这也没有帮助。