Java 项目启动常见报错问题记录
Process finished with exit code 0
清理Maven的org 下 apache 文件夹,让Maven重新下载jar包
或者运行Maven命令,清理jar包
dependency:purge-local-repositoryFailed to configure a DataSource
Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.翻译：无法配置DataSource：未指定'url'属性，也无法配置嵌入数据源。
报错原因：数据库配置未配置或者不正确
解决方法：
1、项目配置文件中没有配置spring-datasource-url属性或者拼写格式错误
spring:
datasource:
url: jdbc:mysql://localhost:3306/read_data?useUnicode=true&characterEncoding=UTF-8&useSSL=false
username: root
password: 123456
driver-class-name: com.mysql.jdbc.Driver2、启动类头部声明
@SpringBootApplication(exclude= {DataSourceAutoConfiguration.class}) 3、项目的依赖需要配置数据源
解决办法就是在当前工程导入其他工程依赖时，把其它工程里需要配置dataSource的依赖给exclude掉
<dependency>
<groupId>com.xuecheng</groupId>
<artifactId>xc-framework-model</artifactId>
<version>0.0.1-SNAPSHOT</version>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</exclusion>
</exclusions>
</dependency>4、配置 spring-datasource-url的文件没有加载（有些配置了反倒不行）
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.yml</include>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.yml</include>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>5、resources 文件夹是普通文件夹，需要设置为 Resources root
6、每个 application-xx.properties 文件都需要正确配置（注意名字）
MybatisPlusException: not find
报错原因：entity包下无实例类
Caused by: com.baomidou.mybatisplus.exceptions.MybatisPlusException: not find typeAliasesPackage:classpath*:com/dxjy/pcr/modules/*/entity/*.class
at com.baomidou.mybatisplus.toolkit.PackageHelper.convertTypeAliasesPackage(PackageHelper.java:76)
... 39 common frames omittedIncorrect integer value
Cause: java.sql.SQLException: Incorrect integer value: 'file' for column 'type' at row 1\n; uncategorized SQLException; SQL state [HY000]; error code [1366]; Incorrect integer value: 'file' for column 'type' at row 1; nested exception is java.sql.SQLException: Incorrect integer value: 'file' for column 'type' at row 1报错原因：数据库字段和实体类类型不对应
The alias 'xxx' is already mapped to the value '..xxx'.
报错原因：xxx实体的类名冲突了
The port may already be in use or the connector may be misconfigured.
Description:
The Tomcat connector configured to listen on port 8082 failed to start. The port may already be in use or the connector may be misconfigured.
Action:
Verify the connector's configuration, identify and stop any process that's listening on port 8082, or configure this application to listen on another port.
报错原因：8082端口占用
解决办法：
netstat -ano|findstr 8005(端口号)
taskkill /pid 22376 /f (22376为对应的pid)SprngBoot引用外部jar包和本身日志接口冲突问题解决办法
If you are using WebLogic you will need to add 'org.slf4j' to prefer-application-packages in WEB-INF/weblogic.xml: org.slf4j.impl.SimpleLoggerFactory解决办法：
starter-web 启动依赖中剔除slf4j
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
</exclusion>
</exclusions>或者添加依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>Caused by: java.lang.ClassNotFoundException: Cannot find class: com.dxjy.pcr.entity.SysLogEntity
原因：SysLogEntity 类找不到
Caused by: java.lang.IllegalArgumentException: Property 'sqlSessionFactory' or 'sqlSessionTemplate' are required
在配置springboot+mysql时，会出现"Property 'sqlSessionFactory' or 'sqlSessionTemplate' are required"显示需要需要将sqlSessionFactory依赖注入。
解决方案：在pom.xml文件内添加如下依赖，然后重新刷新一下maven库即可。
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.1</version>
</dependency>