SpringBoot2.0实战 | 第四章：配置Interceptor拦截器

目标

学会在 SpringBoot 的项目中怎么配置拦截器

操作步骤

添加依赖

引入 Spring Boot Starter 父工程

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.5.RELEASE</version>
</parent>

整体依赖如下所示

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

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

编码

编写拦截器

public class TraceInterceptor implements HandlerInterceptor {

    private static final Logger log = LoggerFactory.getLogger(TraceInterceptor.class);

    /**
     * 预处理回调函数
     * 进入Controller之前执行
     * 如果返回 true，则进入下一个拦截器，所有拦截器全部通过，则进入 Controller 相应的方法
     * 如果返回 false，则请求被拦截。
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String uri = request.getRequestURI();
        log.info("<-----------------------------------");
        log.info("request uri: {}", uri);
        log.info("----------------------------------->");
        return true;
    }

    /**
     * 后处理回调方法
     * 经过Controller处理之后执行
     * 在此处可以对模型数据进行处理或对视图进行处理
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("entry postHandler");

    }

    /**
     * 整个请求处理完毕回调方法，即在视图渲染完毕时回调
     * 在此处可以进行一些资源清理
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    }
}

注册拦截器

WebMvcConfigurer 接口提供了对 SpringMVC 的个性化配置。
实现 WebMvcConfigurer 接口的 addInterceptors 方法进行拦截器的注册。

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(traceInterceptor());
    }

    @Bean
    public TraceInterceptor traceInterceptor() {
        return new TraceInterceptor();
    }

}

Controller 层代码

@RestController
public class HelloController {

    @GetMapping("/hello")
    public String hello() {
        return "hello world";
    }

}

启动类

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

验证结果

编写测试用例

@RunWith(SpringRunner.class)
@WebAppConfiguration
@SpringBootTest(classes = Application.class)
public class TraceInterceptorTest {

    private MockMvc mvc;

    @Autowired
    private WebApplicationContext webApplicationContext;

    @Before
    public void setUp() {
        mvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
    }

    @Test
    public void testInsert() throws Exception {
        MvcResult mvcResult = mvc.perform(
                MockMvcRequestBuilders
                        .get("/hello")
        )
        .andDo(MockMvcResultHandlers.print())
        .andReturn();

        Assert.assertEquals(200, mvcResult.getResponse().getStatus());
    }

}