SpringBoot整合web、Mybatis

Web整合

RestController更加激进的前后端分离

所有的requestMapping返回的都是json数据

package com.bamzhy.controller;

@RestController
public class MyController {
    @Autowired
    MyConfig config;

    @RequestMapping("/haha")
    public MyConfig test(){
        return config;
    }
}

注册Servlet,Filter,Listener

因为web组件都被spring接管了，你自己要单独编写configuration告诉spring我要用这些组件

• configuration

package com.bamzhy.config;

@Configuration
public class MyWebConfig extends WebMvcConfigurationSupport {
    @Autowired
    MyServlet servlet;
    @Bean
    public ServletRegistrationBean getServletRegistrationBean(){
        return new ServletRegistrationBean(servlet,"/myservlet");
    }
}

• servlet

package com.bamzhy.servlet;

@Component
public class MyServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    }
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.getWriter().println("Hello,springBoot Servlet!");
    }
}

• configuration

package com.bamzhy.config;
@Configuration
public class MyWebConfig extends WebMvcConfigurationSupport {
    @Autowired
    MyFilter filter;
    @Bean
    public FilterRegistrationBean getFilterRegistrationBean(){
        FilterRegistrationBean filterFilterRegistrationBean = new FilterRegistrationBean();
        filterFilterRegistrationBean.setFilter(filter);
        filterFilterRegistrationBean.addUrlPatterns("/myservlet/*");
        return filterFilterRegistrationBean;
    }
}

• Filter

package com.bamzhy.filter;

@Component
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("before");
        filterChain.doFilter(servletRequest,servletResponse);
        System.out.println("after");
    }

    @Override
    public void destroy() {
    }
}

• listener

package com.bamzhy.listener;

@Component
public class MyListener implements ServletContextListener {
    @Override
    public void contextInitialized(ServletContextEvent servletContextEvent) {
        System.out.println("this is listener");
    }

    @Override
    public void contextDestroyed(ServletContextEvent servletContextEvent) {
    }
}

    @Bean
    public ServletListenerRegistrationBean getServletListenerRegistrationBean(){
        return new ServletListenerRegistrationBean(listener);
    }

• tip
  Spring2.0之后 Filter listener 不需要配置，只要定义了就默认生效。

注册拦截器interceptor

@Component
public class MyInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        System.out.println("My Interceptor");
        return true;
    }
}

@Configuration
public class MyWebConfig2  implements WebMvcConfigurer {
    @Autowired
    MyInterceptor interceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(interceptor).addPathPatterns("/*");
    }
}

模板引擎

• 先增加FreeMarker的依赖

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>

• 模板文件和控制器
  
  
• Volecity
• Thymelea
  这俩模板技术可以自己参考文档，我是不想看了^_^

Mybatis整合

• 如果一开始没有配置jdbc的连接信息，就运行程序会报错
• applicationproperties

spring.datasource.url=jdbc:mysql://localhost:3306/mybatis
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=12345

• bean类

public class User {
    int id ;
    String username;
    String password;
    String email;
    int  age;

• 接口类（mapper）

package com.bamzhy.ssmdemo.dao;

import com.bamzhy.ssmdemo.bean.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
@Mapper
public interface UserDao {
    @Select("select * from user where id =#{id}")
    User findUserById(int id );
}

• service类

package com.bamzhy.ssmdemo.service;

@Service
public class UserService {
    @Autowired
    UserDao dao;
    public User findUserById(int id) {
        return  dao.findUserById(id);
    }
}

• controller

package com.bamzhy.ssmdemo.controller;
@RestController
public class MyController  {
    @Autowired
    UserService service;
    @RequestMapping("/user/{id}")
    public User getUserById(@PathVariable("id") int id){
        User userById = service.findUserById(id);
        return userById;
    }
}

• 如果使用test方法
  记得加上@SpringBootTest(classes = SsmdemoApplication.class)
• 可以使用注解或者xml的方法
  而xml的位置如下
  

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.bamzhy.ssmdemo.dao.UserDao">

    <select id="findUserById" parameterType="int" resultType="com.bamzhy.ssmdemo.bean.User">
        SELECT *FROM user WHERE id = #{xx}
    </select>


    <select id="findUserByName" parameterType="string" resultType="com.bamzhy.ssmdemo.bean.User">

        SELECT *FROM user WHERE username = #{xx}

    </select>
</mapper>

注解和xml可以同时存在

• @Param注解
  可以让接口里传入多个参数
  在userdao(mapper)里边定义

@Mapper
public interface UserDao {
    @Select("select * from user where id =#{id} and username=#{username}")
    User findUserById(@Param("id")int id, @Param("username") String username);
}

• 引入Mybatis配置文件
  在application.properties中加入
  mybatis.config-location=mybatis.xml
  mybatis的相关配置与之前无异

• 开启事务
  在SsmdemoApplication上边加@EnableTransactionManagement
  在需要加事务的接口上加@Transaction(readOnly = true)，该操作只读，要是发生修改则报错。
  如果操作不成功则回滚。