Spring in Action 5th edition Chapter 1 & 2

技术2022-07-11 70

Chapter I & II

How to write a controllerHow to write a templateHow to add attributes to Model objectHow to perform validationHow to write a “controller” which does simple things

How to write a controller

@Controller @RequestMapping("/path") public class MyCOntroller { @GetRequest public String getMapping(Model model) { model.addAttribute("...", ...); //How to add attributes to Model object ... return "templateName"; } @PostRequest public String getMapping(@Valid @ModelAttribute('attrName') MyClass onject, Errors errors) { if (errors.hasErrors()) { // Perform validation //do something for the error } //do something (business logic) return "templateName"; } }

How to write a template

Example.

<!DOCTYPE html> <html lang="en" xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Post Course</title> </head> <body> <form method="post" th:object="${course}"> <h3>Enter course name: </h3> <input type="text" th:field="*{name}"/>  <span th:if="${#fields.hasErrors('name')}" th:errors="*{name}">Name Error</span> <h3>Enter lecture sections</h3> <textarea th:field="*{lecs}"></textarea> <h3>Enter tutorial sections</h3> <textarea th:field="*{tuts}"></textarea> <h3>Enter lab sections</h3> <textarea th:field="*{labs}"></textarea> <button>Submit your course</button> </form> </body> </html>

Key points

How to perform validation

Combine with the previous code, in model class add annotations:

@Data //@Data is lombok annotation which auto generates constructor, getters, and setters for the fields. public class MyClass { @Size(min=3, message="error message") // there are other constrains, such as @Pattern... private String someInfo; ... }

How to write a “controller” which does simple things.

@Configuration public class WebConfig implements WebMvcConfigurer { @Override public void addViewControllers(ViewControllerRegistry registry) { registry.addViewController("/path").setViewName("viewName"); } }

Other

@Slf4j: is in lombok which provides a logger. (Simply log.info("info");)

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Spring in Action 5th edition Chapter 1 &amp; 2