服务端开发(2) Web MVC
2023-08-09 14:53:19 # NJU # 服务端开发

Taco示例

1. lombok

编译期后就不需要了，要排除

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<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    <configuration>
      <excludes>
        <exclude>
          <groupId>org.projectlombok</groupId>
          <artifactId>lombok</artifactId>
        </exclude>
      </excludes>
    </configuration>
</plugin>

2. DesignTacoController控制器实现

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@Slf4j
@Controller
@RequestMapping("/design")
@SessionAttributes("tacoOrder")
public class DesignTacoController {
    ...
    /** @Slf4j 可替代 
     *	private static final org.slf4j.Logger log = 
     *  	org.slf4j.LoggerFactory.getLogger(DesignTacoController.class);
   	 */ 
}

3. Spring MVC的请求映射注解

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@RequestMapping
@GetMapping
@PostMapping
@PutMapping
@DeleteMapping
@PatchMapping

4. 设计视图

使用 thymeleaf

5. 处理表单提交

5.1 Converter

前端返回的是String, 后端需要的是 Ingredient, 如何解决

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<input th:field="*{ingredients}" type="checkbox" 
               th:value="${ingredient.id}"/>
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@NotNull
@Size(min=1, message="You must choose at least 1 ingredient")
private List<Ingredient> ingredients;

使用 Spring 提供的 Converter 来解决

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@Component
public class IngredientByIdConverter implements Converter<String, Ingredient> {

  private Map<String, Ingredient> ingredientMap = new HashMap<>();
  
  @Override
  public Ingredient convert(String id) {
    return ingredientMap.get(id);
  }
}

5.2 rediect重定向

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return "redirect:/orders/current";

image-20230302210339075

6. 校验表单输入

  • JavaBean Validation API
  • spring-boot-starter-validation
  • 领域类上添加校验规则
  • 控制器中声明校验：@Valid
  • 修改表单视图以展现校验错误
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@Data
public class Taco {

  @NotNull
  @Size(min=5, message="Name must be at least 5 characters long")
  private String name;

  @NotNull
  @Size(min=1, message="You must choose at least 1 ingredient")
  private List<Ingredient> ingredients;

}
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@PostMapping
public String processTaco(@Valid Taco taco,
                          Errors errors,
                          @ModelAttribute TacoOrder tacoOrder) {
	...
}

7. 使用视图控制器

  • 接口 WebMvcConfigurer，用于配置
  • 简单的从请求URL到视图
    • registry.addViewController("/").setViewName("home");
    • 如果路径是 “/“, 直接返回 home 视图
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2023-08-09 14:53:19 # NJU # 服务端开发
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