使用mybatis+SpringBoot完成第一个查询demo

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使用mybatis+SpringBoot完成第一个查询demo

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>Chapter</artifactId>
        <groupId>com.course.code</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>Chapter13</artifactId>
    <packaging>pom</packaging>
    <build>

            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <configuration>
                        <source>1.8</source>
                        <target>1.8</target>
                    </configuration>
                </plugin>
            </plugins>

    </build>
    <properties>
        <swagger.version>2.6.1</swagger.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.1.2</version>
        </dependency>
        <dependency>
            <groupId>org.testng</groupId>
            <artifactId>testng</artifactId>
            <version>6.10</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>${swagger.version}</version>
        </dependency>
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>${swagger.version}</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.47</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.14</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <!--把 mysql mybatis spring 这三个结合在一起的 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
        </dependency>
        <!--引入测试报告相关包-->
        <dependency>
            <groupId>com.relevantcodes</groupId>
            <artifactId>extentreports</artifactId>
            <version>2.41.1</version>
            <exclusions>
                <exclusion>
                    <artifactId>mongodb-driver</artifactId>
                    <groupId>org.mongodb</groupId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>com.vimalselvam</groupId>
            <artifactId>testng-extentsreport</artifactId>
            <version>1.3.1</version>
        </dependency>
        <dependency>
            <groupId>com.aventstack</groupId>
            <artifactId>extentreports</artifactId>
            <version>3.0.6</version>
            <exclusions>
                <exclusion>
                    <artifactId>mongodb-driver</artifactId>
                    <groupId>org.mongodb</groupId>
                </exclusion>
            </exclusions>
        </dependency>
  
    </dependencies>
</project>

<?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.course">
    <select id="getUserCount" parameterType="com.course.model.User" resultType="Integer">
        select count(*) from user;
    </select>

</mapper>

当引入了包，但是报错说没有这个方法，说明是引入的包有问题，那就是这个包的版本不对，包冲突导致的，引入这个包

spring-boot-starter-web的时候不带版本号，这里面没有mybatis，所以还要引入mybatis-spring-boot-starter，需要带版本号，一般springboot1.5.3, mybatis1.3.1就可以支持

@EnableScheduling
@SpringBootApplication
public class Application {
    private  static ConfigurableApplicationContext context;
    public static void main(String[] args) {
        Application.context = SpringApplication.run(Application.class,args);
    }
    @PreDestroy
    public void close(){
        Application.context.close();
    }
}

public class Demo {
    /**
     * 首先获取一个执行sql语句的对象
     * @Autowired这个注解的含义是启动及加载，
     * 启动这个Demo类，
     * 这个对象就被加载了
     */
    @Autowired
    private SqlSessionTemplate template;
    
    @RequestMapping(value = "getUserList",method = RequestMethod.GET)
    @ApiOperation(value = "可以获取到用户数",httpMethod = "GET")
    public int getUserCount(){
      return template.selectOne("getUserCount");
    }
}