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Bug1:

java.lang.NullPointerException: inStream parameter is null
	at java.base/java.util.Objects.requireNonNull(Objects.java:246)
	at java.base/java.util.Properties.load(Properties.java:403)
	at cn.itcast.travel.util.JDBCUtils.<clinit>(JDBCUtils.java:31)
	at cn.itcast.travel.dao.impl.UserDaoImpl.<init>(UserDaoImpl.java:10)
	at cn.itcast.travel.service.impl.UserServiceImpl.<init>(UserServiceImpl.java:9)
	at cn.itcast.travel.web.servlet.RegistUserServlet.doPost(RegistUserServlet.java:37)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:835)
3月 10, 2020 8:24:35 下午 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet [cn.itcast.travel.web.servlet.RegistUserServlet] in context with path [/travel] threw exception

原因：


JDBCUtils.java文件中加载配置文件中的数据格式错误：

修改如下：
// 2. 创建连接池对象
	static {
		// 加载配置文件中的数据
		InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
		Properties pp = new Properties();
		try {
			pp.load(is);
			// 创建连接池，使用配置文件中的参数
			ds = DruidDataSourceFactory.createDataSource(pp);
		} catch (IOException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

Bug2:

java.sql.SQLException: java.lang.ClassCastException: class java.math.BigInteger cannot be cast to class java.lang.Long (java.math.BigInteger and java.lang.Long are in module java.base of loader 'bootstrap')
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1078)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:975)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:920)
	at com.mysql.jdbc.ConnectionImpl.buildCollationMapping(ConnectionImpl.java:1074)
	at com.mysql.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:3593)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2534)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2304)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:481)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:346)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1375)
	at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1431)
	at com.alibaba.druid.pool.DruidDataSource.init(DruidDataSource.java:618)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:915)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:911)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:98)
	at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111)
	at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
	at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:630)
	at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:695)
	at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:727)
	at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:737)
	at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:811)
	at cn.itcast.travel.dao.impl.UserDaoImpl.findByUsername(UserDaoImpl.java:17)
	at cn.itcast.travel.service.impl.UserServiceImpl.regist(UserServiceImpl.java:15)
	at cn.itcast.travel.web.servlet.RegistUserServlet.doPost(RegistUserServlet.java:38)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:835)

原因：


pom.xml文件中导入的mysql驱动jar问题，原因是本地mysql版本升级成了8.0.19，jar包还是原来的版本。所以把pom.xml文件中的对应jar包改成本地安装的对应版本jar包。

Bug3:

java.lang.NullPointerException
	at com.alibaba.druid.pool.vendor.MySqlValidConnectionChecker.<init>(MySqlValidConnectionChecker.java:48)
	at com.alibaba.druid.pool.DruidDataSource.initValidConnectionChecker(DruidDataSource.java:878)
	at com.alibaba.druid.pool.DruidDataSource.init(DruidDataSource.java:594)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:915)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:911)
	at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:98)
	at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111)
	at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77)
	at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:630)
	at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:695)
	at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:727)
	at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:737)
	at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:811)
	at cn.itcast.travel.dao.impl.UserDaoImpl.findByUsername(UserDaoImpl.java:17)
	at cn.itcast.travel.service.impl.UserServiceImpl.regist(UserServiceImpl.java:15)
	at cn.itcast.travel.web.servlet.RegistUserServlet.doPost(RegistUserServlet.java:38)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
	at java.base/java.lang.Thread.run(Thread.java:835)

原因：





druid.properties配置文件中：


1.由于Bug2中导入了mysql的高版本jar包（6及以上），所以驱动名要修改为：

driverClassName=com.mysql.cj.jdbc.Driver//6版本及以后

2.url名后要添加：

?serverTimezone=GMT%2B8

3.当然数据库的用户名和密码也对应要修改为自己的。

修改之后的配置文件：