springboot整合mybatis+jetty笔记以及遇到的问题

1. 图文创建一个springboot Demo(IDEA创建)+目录图+返回json

   springboot创建参考

   

   

2. pom.xml　

   1.   <dependencies>
               <!--<dependency>-->
                   <!--<groupId>org.springframework.boot</groupId>-->
                   <!--<artifactId>spring-boot-starter-data-jpa</artifactId>-->
               <!--</dependency>-->
               <dependency>
                   <groupId>org.springframework.boot</groupId>
                   <artifactId>spring-boot-starter-web</artifactId>
                   <exclusions>
                       <exclusion>
                           <groupId>org.springframework.boot</groupId>
                           <artifactId>spring-boot-starter-tomcat</artifactId>
                       </exclusion>
                   </exclusions>
               </dependency>
      
               <dependency>
                   <groupId>org.springframework.boot</groupId>
                   <artifactId>spring-boot-starter-jetty</artifactId>
               </dependency>
      
               <dependency>
                   <groupId>org.mybatis.spring.boot</groupId>
                   <artifactId>mybatis-spring-boot-starter</artifactId>
                   <version>1.3.2</version>
               </dependency>
      
               <dependency>
                   <groupId>mysql</groupId>
                   <artifactId>mysql-connector-java</artifactId>
                   <!--<scope>runtime</scope>-->
               </dependency>
      
               <dependency>
                   <groupId>org.projectlombok</groupId>
                   <artifactId>lombok</artifactId>
                   <optional>true</optional>
               </dependency>
      
               <dependency>
                   <groupId>org.springframework.boot</groupId>
                   <artifactId>spring-boot-starter-test</artifactId>
                   <scope>test</scope>
               </dependency>
      
               <dependency>
                   <groupId>org.springframework.boot</groupId>
                   <artifactId>spring-boot-autoconfigure</artifactId>
                   <version>2.1.0.RELEASE</version>
               </dependency>
      
               <dependency>
                   <groupId>javax.servlet</groupId>
                   <artifactId>javax.servlet-api</artifactId>
                   <version>3.1.0</version>
               </dependency>
      
               <dependency>
                   <groupId>com.google.guava</groupId>
                   <artifactId>guava</artifactId>
                   <version>19.0</version>
                   <!--<version>1.1.9</version>-->
               </dependency>
      
               <!--阿里巴巴用来监控mysql线程池-->
               <dependency>
                   <groupId>com.alibaba</groupId>
                   <artifactId>druid</artifactId>
                   <version>1.1.9</version>
               </dependency>
      
           </dependencies>
      
           <build>
               <plugins>
                   <plugin>
                       <groupId>org.springframework.boot</groupId>
                       <artifactId>spring-boot-maven-plugin</artifactId>
                   </plugin>
               </plugins>
           </build>

3. application.properties配置数据库　

   1.  server.port=8090
       ## 数据源配置
       spring.datasource.url=jdbc:mysql://localhost:3306/xxx?characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2b8
       spring.datasource.username=root
       spring.datasource.password=123456
       #spring.datasource.driver-class-name=com.mysql.jdbc.Driver
       spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
       mybatis.config-location=classpath:/mybatis/mybatis-config.xml

   2. 有时候url只是配置characterEncoding=utf-8参数 会报错

4. mybaits.xml的配置

   1.  <?xml version="1.0" encoding="UTF-8"?>
       <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
               "http://mybatis.org/dtd/mybatis-3-config.dtd">
       <configuration>
           <settings>
               <!--配置关闭缓存-->
               <!--缓存开关-->
               <setting name="cacheEnabled" value="false"/>
               <!--自动启动驼峰原则-->
               <setting name="mapUnderscoreToCamelCase" value="true"/>
               <!-- 允许 JDBC 支持自动生成主键，需要驱动兼容。 如果设置为 true 则这个设置强制使用自动生成主键，尽管一些驱动不能兼容但仍可正常工作（比如 Derby）。 默认值false  -->
               <setting name="useGeneratedKeys" value="true"/>
               <!--  配置默认的执行器。SIMPLE 就是普通的执行器；REUSE 执行器会重用预处理语句（prepared statements）； BATCH 执行器将重用语句并执行批量更新。默认SIMPLE  -->
               <setting name="defaultExecutorType" value="REUSE"/>
               <!-- 设置超时时间，它决定驱动等待数据库响应的秒数。 -->
               <setting name="defaultStatementTimeout" value="600"/>
      
           </settings>
      
           <typeAliases >
               <typeAlias type="com.mooc.house.common.model.User" alias="user"></typeAlias>
           </typeAliases>
      
           <mappers>
               <mapper resource="mapper/myUser.xml"/>
           </mappers>
      
       </configuration>

5. mapper xml的配置

   1.  <?xml version="1.0" encoding="UTF-8" ?>
       <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
       <mapper
        namespace="com.xx.xx.mapper.UserMapper">
           <select id="xxx" resultType="user">
               select xxx from user
           </select>
       </mapper>

6. controller层

   1.  @RestController
       public class UserController {
           @Autowired
           private Userservice userservice;
      
           @RequestMapping("get")
           public List<User> getUsers(){
               return userservice.getUsers();
           }
      
       }

7. service层

   1.  @Service
       public class Userservice {
           @Resource
           private UserMapper userMapper;
      
           public List<User> getUsers(){
               return userMapper.findAllUsers();
           }
       }

8. mapper 接口层　

   1.  @Mapper
       public interface UserMapper {
       //    查询用户
           public List<User> findAllUsers();
       }

9. 启动jetty

10. 返回json