配置方式

public class DemoController implements Controller {
    @Override
    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) {
        // 创建模型视图对象
        ModelAndView mav = new ModelAndView();
        // 设置视图名称
        mav.setViewName("demo");
        // 添加模型数据
        mav.addObject("message", "欢迎");
        // 返回模型视图对象
        return mav;
    }
}

@Controller
public class DemoController {
    @RequestMapping(value = "/demo")
    public ModelAndView demo() {
        // 创建模型视图对象
        ModelAndView mav = new ModelAndView();
        // 设置视图名称
        mav.setViewName("demo");
        // 添加模型数据
        mav.addObject("message", "欢迎");
        // 返回模型视图对象
        return mav;
    }
}

@Controller
public class DemoController {
    @RequestMapping(value = "/demo")
    public ModelAndView demo() {
        // 创建模型视图对象
        ModelAndView mav = new ModelAndView();
        // 设置视图名称
        mav.setViewName("demo");
        // 添加模型数据
        mav.addObject("message", "欢迎");
        // 返回模型视图对象
        return mav;
    }
}

public class WebInitializer implements WebApplicationInitializer {
    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {
        // 创建AnnotationConfigWebApplicationContext容器，支持在Web环境中使用注解的方式获取配置
        AnnotationConfigWebApplicationContext webContext = new AnnotationConfigWebApplicationContext();
        // 注册Web配置类，比如Controller控制器类
        webContext.register(WebConfig.class);

        // 配置前端控制器
        DispatcherServlet dispatcherServlet = new DispatcherServlet(webContext);
        ServletRegistration.Dynamic registration = servletContext.addServlet("dispatcher", dispatcherServlet);
        // 配置DispatcherServlet映射URL
        registration.addMapping("/");
        // 在应用启动时立即加载
        registration.setLoadOnStartup(1);

        // 注册字符编码过滤器
        FilterRegistration.Dynamic encodingFilter = servletContext.addFilter("encodingFilter", CharacterEncodingFilter.class);
        encodingFilter.setInitParameter("encoding", "UTF-8");
        encodingFilter.setInitParameter("forceEncoding", "true");
        encodingFilter.addMappingForUrlPatterns(null, true, "/*");
    }
}

@Configuration
@EnableWebMvc
@ComponentScan("com.example.controller")
public class WebConfig implements WebMvcConfigurer {
    // 配置视图解析器
    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("/WEB-INF/views/");
        resolver.setSuffix(".jsp");
        resolver.setContentType("text/html;charset=UTF-8");
        return resolver;
    }
}

public class WebInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
    // 指定根配置类，在核心容器中创建，具有唯一性
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[0];
    }
    // 指定Web配置类，在MVC容器中创建，可以有多个
    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[] {WebConfig.class};
    }
    // 指定映射路径
    @Override
    protected String[] getServletMappings() {
        // 设置DispatcherServlet的映射路径
        return new String[] {"/"};
    }
    // 指定过滤器
    @Override
    protected Filter[] getServletFilters() {
        // 注册字符编码过滤器
        CharacterEncodingFilter encodingFilter = new CharacterEncodingFilter();
        encodingFilter.setEncoding("UTF-8");
        encodingFilter.setForceEncoding(true);
        return new Filter[] {encodingFilter};
    }
}

@Configuration
@EnableWebMvc
@ComponentScan("com.example.controller")
public class WebConfig implements WebMvcConfigurer {
    // 配置静态资源映射
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/static/**").addResourceLocations("/static/");
    }
    // ...
}

@Configuration
@EnableWebMvc
@ComponentScan("com.example.controller")
public class WebConfig implements WebMvcConfigurer {
    // 配置消息转换器，设置编码格式，处理返回String类型的响应
    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
        // 遍历消息转换器列表
        for (int i = 0; i < converters.size(); i++) {
            // 修改原始StringHttpMessageConverter转换器
            if (converters.get(i) instanceof StringHttpMessageConverter) {
                // 设置UTF-8编码
                StringHttpMessageConverter custom = new StringHttpMessageConverter(StandardCharsets.UTF_8);
                // 设置为false可以避免响应头过大
                custom.setWriteAcceptCharset(false);
                // 替换原始StringHttpMessageConverter转换器
                converters.set(i, custom);
                break;
            }
        }
    }
    // ...
}

public class DemoMessageConverter implements HttpMessageConverter {
    @Override
    public boolean canRead(Class clazz, MediaType mediaType) {
        return User.class.isAssignableFrom(clazz);
    }
    @Override
    public boolean canWrite(Class clazz, MediaType mediaType) {
        return User.class.isAssignableFrom(clazz);
    }
    @Override
    public List<MediaType> getSupportedMediaTypes() {
        return Collections.singletonList(new MediaType("application", "x-demo"));
    }
    @Override
    public Object read(Class clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
        String body = StreamUtils.copyToString(inputMessage.getBody(), StandardCharsets.UTF_8);
        Map<String, String> param = Arrays.stream(body.split(";"))
                .map(data -> data.split(":"))
                .collect(Collectors.toMap(data -> data[0], data -> data[1]));
        User user = new User();
        user.setId(Integer.parseInt(param.get("id")));
        user.setName(param.get("name"));
        return user;
    }
    @Override
    public void write(Object o, MediaType contentType, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException {
        User user = (User) o;
        String body = String.format("id:%d;name:%s", user.getId(), user.getName());
        StreamUtils.copy(body.getBytes(StandardCharsets.UTF_8), outputMessage.getBody());
    }
}

@Configuration
@EnableWebMvc
@ComponentScan("com.example.controller")
public class WebConfig implements WebMvcConfigurer {
    // 配置消息转换器
    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(new DemoMessageConverter());
    }
    // ...
}

@Controller
public class DemoController {
    @PostMapping("/demo")
    @ResponseBody
    public User demo(@RequestBody User user) {
        return user;
    }
}

@Configuration
@EnableWebMvc
@ComponentScan("com.example.controller")
public class WebConfig implements WebMvcConfigurer {
    // 配置内容协商策略
    @Override
    public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
        // 注册自定义媒体类型
        MediaType APPLICATION_X_DEMO = new MediaType("application", "x-demo");
        // 配置支持的媒体类型
        Map<String, MediaType> mediaTypes = new HashMap<>();
        mediaTypes.put("json", MediaType.APPLICATION_JSON);
        mediaTypes.put("xml", MediaType.APPLICATION_XML);
        mediaTypes.put("x-demo", APPLICATION_X_DEMO);
        // 开启路径参数
        configurer.favorParameter(true);
        // 配置路径参数名，默认将format作为参数名
        configurer.parameterName("content");
        // 配置默认媒体类型
        configurer.defaultContentType(APPLICATION_X_DEMO);
        // 配置支持的媒体类型
        configurer.mediaTypes(mediaTypes);
    }
    // ...
}