Mybatis整合Spring(Maven) 可难死宝宝了

先上结构图们，为了小伙伴们方便

1：首先配置pom.xml(也就是导包)

  4.0.0

  org.example
  Login
  1.0-SNAPSHOT
  war

  Login Maven Webapp
  
  http://www.example.com

  
    UTF-8
    1.7
    1.7
  

  
    
      junit
      junit
      4.11
      test
    
    
      org.springframework
      spring-context
      5.0.5.RELEASE
    
    
      org.springframework
      spring-test
      5.0.5.RELEASE
    
    
      org.springframework
      spring-web
      5.0.5.RELEASE
    
    
      org.springframework
      spring-webmvc
      5.0.5.RELEASE
    
    
      com.fasterxml.jackson.core
      jackson-core
      2.9.0
    
    
      com.fasterxml.jackson.core
      jackson-databind
      2.9.0
    
    
      com.fasterxml.jackson.core
      jackson-annotations
      2.9.0
    
    
      org.springframework
      spring-tx
      5.3.0
    
    
      org.aspectj
      aspectjweaver
      1.7.4
    
    
      org.springframework
      spring-jdbc
      5.3.0
    
    
      org.projectlombok
      lombok
      1.18.12
    
    
    
      org.mybatis
      mybatis
      3.3.0
    
    
      org.mybatis
      mybatis-spring
      1.3.1
    
    
      mysql
      mysql-connector-java
      8.0.25
    
    
      log4j
      log4j
      1.2.13
    
    
      c3p0
      c3p0
      0.9.1.2
    
  

2：配置web.xml

    
    
        CharacterEncodingFilter
        org.springframework.web.filter.CharacterEncodingFilter
        
            encoding
            UTF-8
        
    
    
        CharacterEncodingFilter
        /*
    

    
    
        contextConfigLocation
        classpath:applicationContext.xml
    
    
    
        org.springframework.web.context.ContextLoaderListener
    


    
    
        DispatcherServlet
        org.springframework.web.servlet.DispatcherServlet
        
            contextConfigLocation
            classpath:spring-mvc.xml
        
        2
    
    
        DispatcherServlet
        /
    

 3:开始配置jdbc.properties log4j.properties Spring  SpringMVC  Mybatis 配置文件（都是在resources中配置） 4:配置jdbc.properties

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test?characterEncoding=utf-8
jdbc.username=root
jdbc.password=010429

5:log4j.properties

# Global logging configuration
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

6：配置applicationContext.xml

在该xml中配置出现了解决了五个小时得bug(难死宝宝了)

在配置MyBatis核心文件时必须要加上

如果没有该行代码，在tomcat运行完之后访问接口将会出现500错误

7:配置spring-mvc.xml

8:配置sqlMapConfig.xml

9：在resources中建立一个mapper包，在mapper包下面写配置sql文件，起名为UserMapper.xml(当然，也可以给namespace中起别名)

    
        select count(*) from Student;
    

10：上mapper，service，controller代码。

（1）：mapper层

@Component
public interface UserMapper {
    Integer  query();
}

（2）：service层（在该层中在Impl中加入@Service注解和 @Autowired自动注入）

     接口

public interface UserService {

    int queryAll();
}

具体实现类

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public int queryAll() {
       return userMapper.query();
    }
}

 （3）Controller层（根据自己需要去实现）11

@Controller
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping("/find")
    @ResponseBody
    public Integer queryAll(){
        int i =userService.queryAll();
        System.out.println("从后台中查到了"+i+"条记录");
        return i;
    }
}

11：上结果图