1. Failed to configure a DataSource: ‘url’ attribute is not specified and no embedded datasource could be configured

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class


Action:

Consider the following:
	If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.
	If you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).

原因：引入mybatis的jar包时：

<dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
</dependency>

springboot会默认加载org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration这个类，而DataSourceAutoConfiguration类使用了@Configuration注解向spring注入了dataSource bean，又因为项目中并没有关于dataSource相关的配置信息，所以当spring创建dataSource bean时因缺少相关的信息就会报错。

解决办法：

在@SpringBootApplication注解上加上exclude，解除自动加载DataSourceAutoConfiguration。

@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

在parent项目的pom.xml文件中保存所有子模块的共有jar依赖，非共有的依赖则在各模块自身的pom.xml文件中进行申明。建议采用此方法，好处在于各模块的依赖不会相互产生干扰。

2.maven配置时，测试出现“’mvn’ 不是内部或外部命令,也不是可运行的程序”错误

配置maven。

在环境变量的PATH中配置maven的bin目录。

使用mvn package打包成功后显示日志：

-----------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 46.791 s
[INFO] Finished at: 2018-11-21T16:12:36+08:00
[INFO] Final Memory: 35M/275M
[INFO] ------------------------------------------------------------------------

3.java.sql.SQLException: The server time zone value ‘???ú±ê×??±??’ is unrecognized or represents……..

具体错误：

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
Tue May 15 21:38:04 CST 2018 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
java.sql.SQLException: The server time zone value '???ú±ê×??±??' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:127)
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:95)
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:87)
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:61)
	at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:71)
	at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:76)
 
 
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:862)
	at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:444)
	at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:230)
 
 
	at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:226)
	at java.sql.DriverManager.getConnection(Unknown Source)
	at java.sql.DriverManager.getConnection(Unknown Source)
	at zhu.jdbc.unit.UnitMysql.getConnection(UnitMysql.java:34)
	at zhu.jdbc.dao.imp.ITb_UserImpI.insertData(ITb_UserImpI.java:55)
	at zhu.jdbc.dao.imp.ITb_UserImpI.insertData(ITb_UserImpI.java:1)
	at zhu.jdbc.service.imp.ITb_UserServiceImpI.insertData(ITb_UserServiceImpI.java:35)
	at zhu.jdbc.service.imp.ITb_UserServiceImpI.insertData(ITb_UserServiceImpI.java:1)
	at zhu.jdbc.servlet.Servlet_TbUser.Insert(Servlet_TbUser.java:87)
	at zhu.jdbc.servlet.Servlet_TbUser.doPost(Servlet_TbUser.java:41)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:496)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790)
 
 
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Unknown Source)
Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '???ú±ê×??±??' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
	at java.lang.reflect.Constructor.newInstance(Unknown Source)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:59)
	at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:83)
	at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:128)
	at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2201)
	at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2225)
	at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1391)
	at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:993)
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:852)
	... 36 more
五月 15, 2018 9:38:04 下午 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet [Servlet_TbUser] in context with path [/myweb2] threw exception
java.lang.NullPointerException
	at zhu.jdbc.dao.imp.ITb_UserImpI.insertData(ITb_UserImpI.java:59)
	at zhu.jdbc.dao.imp.ITb_UserImpI.insertData(ITb_UserImpI.java:1)
	at zhu.jdbc.service.imp.ITb_UserServiceImpI.insertData(ITb_UserServiceImpI.java:35)
	at zhu.jdbc.service.imp.ITb_UserServiceImpI.insertData(ITb_UserServiceImpI.java:1)
	at zhu.jdbc.servlet.Servlet_TbUser.Insert(Servlet_TbUser.java:87)
	at zhu.jdbc.servlet.Servlet_TbUser.doPost(Servlet_TbUser.java:41)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:496)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459)
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
 
	at java.lang.Thread.run(Unknown Source)

出现这个的原因是因为 mysql返回的时间总是有问题，比实际时间要早8小时。

解决办法：

在jdbc连接的url后面加上serverTimezone=GMT即可解决问题，如果需要使用gmt+8时区，需要写成GMT%2B8。

为了防止因为日期为null报错，可以直接加上：

?serverTimezone=UTC&zeroDateTimeBehavior=convertToNull

例如链接数据库，可以写为：

jdbc.url=jdbc:mysql://xxx.xxx.xxx.xxx/xxxxx?serverTimezone=UTC&zeroDateTimeBehavior=convertToNull

4.Loading class com.mysql.jdbc.Driver. This is deprecated. The new driver class is com.mysql.cj.jdbc.Driver. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.

这个问题是使用了新的mysql驱动包，但驱动声明不是最新的：

DriverClassName 从 “com.mysql.jdbc.Driver” 换成 “com.mysql.cj.jdbc.Driver” 即可。

5.spring Failed to convert property value of type ‘java.lang.String’ to required type ‘int’ for property

原错误是不能将long的null属性转化出来，但是没找到原来的错误。采取的方式是，把pojo类中的long全改为Integer。

如果是date出错，参考问题3，在数据库连接时加上zeroDateTimeBehavior=convertToNull。

6. This application has no explicit mapping for /…

原因1:
Application启动类的位置不对.要将Application类放在最外侧,即包含所有子包
原因:spring-boot会自动加载启动类所在包下及其子包下的所有组件.

原因2:
在springboot的配置文件:application.yml或application.properties中关于视图解析器的配置问题:
当pom文件下的spring-boot-starter-paren版本高时使用:
spring.mvc.view.prefix/spring.mvc.view.suffix
当pom文件下的spring-boot-starter-paren版本低时使用:
spring.view.prefix/spring.view.suffix

原因3:
控制器的URL路径书写问题
@RequestMapping(“xxxxxxxxxxxxxx”)
实际访问的路径与”xxx”不符合.

原因4：
**application.properties中设置thymeleaf的属性时，注释掉spring.thymeleaf.view-names=，这是可解析的视图名称列表，用逗号分隔，但是如果不写，就会报这个错误。

7.springboot中 server: context-path: /spring报错：Deprecated configuration property

是版本问题，这个新版本不是这种写法：应该变化为：server.servlet.context-path: /spring