Web 页面和Controller
有了Book entity， 我们需要为Book写一个Controller，主要做增删改查的操作，如下所示：
@RestController @RequestMapping("/api/books") public class BookController { @Autowired private BookRepository bookRepository; @GetMapping public Iterable findAll() { return bookRepository.findAll(); } @GetMapping("/title/{bookTitle}") public List findByTitle(@PathVariable String bookTitle) { return bookRepository.findByTitle(bookTitle); } @GetMapping("/{id}") public Book findOne(@PathVariable Long id) { return bookRepository.findById(id) .orElseThrow(BookNotFoundException::new); } @PostMapping @ResponseStatus(HttpStatus.CREATED) public Book create(@RequestBody Book book) { return bookRepository.save(book); } @DeleteMapping("/{id}") public void delete(@PathVariable Long id) { bookRepository.findById(id) .orElseThrow(BookNotFoundException::new); bookRepository.deleteById(id); } @PutMapping("/{id}") public Book updateBook(@RequestBody Book book, @PathVariable Long id) { if (book.getId() != id) { throw new BookIdMismatchException("ID mismatch!"); } bookRepository.findById(id) .orElseThrow(BookNotFoundException::new); return bookRepository.save(book); } }
这里我们使用@RestController 注解，表示这个Controller是一个API，不涉及到页面的跳转。
@RestController是@Controller 和 @ResponseBody 的集合。
异常处理
基本上我们的程序已经完成了，但是在Controller中，我们定义了一些自定义的异常：
public class BookNotFoundException extends RuntimeException { public BookNotFoundException(String message, Throwable cause) { super(message, cause); } // ... }
那么怎么处理这些异常呢？我们可以使用@ControllerAdvice来拦截这些异常：
@ControllerAdvice public class RestExceptionHandler extends ResponseEntityExceptionHandler { @ExceptionHandler({ BookNotFoundException.class }) protected ResponseEntity<Object> handleNotFound( Exception ex, WebRequest request) { return handleExceptionInternal(ex, "Book not found", new HttpHeaders(), HttpStatus.NOT_FOUND, request); } @ExceptionHandler({ BookIdMismatchException.class, ConstraintViolationException.class, DataIntegrityViolationException.class }) public ResponseEntity<Object> handleBadRequest( Exception ex, WebRequest request) { return handleExceptionInternal(ex, ex.getLocalizedMessage(), new HttpHeaders(), HttpStatus.BAD_REQUEST, request); } }
这种异常捕获也叫做全局异常捕获。
测试
我们的Book API已经写好了，接下来我们需要写一个测试程序来测试一下。
这里我们使用@SpringBootTest ：
@Slf4j @RunWith(SpringRunner.class) @SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT) public class SpringContextTest { @Test public void contextLoads() { log.info("contextLoads"); } }
webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT的作用是表示测试时候使用的Spring boot应用程序端口使用自定义在application.properties中的端口。
接下来我们使用RestAssured来测试BookController：
@RunWith(SpringRunner.class) @SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT) public class SpringBootBootstrapTest { private static final String API_ROOT = "http://localhost:8081/api/books"; private Book createRandomBook() { Book book = new Book(); book.setTitle(randomAlphabetic(10)); book.setAuthor(randomAlphabetic(15)); return book; } private String createBookAsUri(Book book) { Response response = RestAssured.given() .contentType(MediaType.APPLICATION_JSON_VALUE) .body(book) .post(API_ROOT); return API_ROOT + "/" + response.jsonPath().get("id"); } @Test public void whenGetAllBooks_thenOK() { Response response = RestAssured.get(API_ROOT); assertEquals(HttpStatus.OK.value(), response.getStatusCode()); } @Test public void whenGetBooksByTitle_thenOK() { Book book = createRandomBook(); createBookAsUri(book); Response response = RestAssured.get( API_ROOT + "/title/" + book.getTitle()); assertEquals(HttpStatus.OK.value(), response.getStatusCode()); assertTrue(response.as(List.class) .size() > 0); } @Test public void whenGetCreatedBookById_thenOK() { Book book = createRandomBook(); String location = createBookAsUri(book); Response response = RestAssured.get(location); assertEquals(HttpStatus.OK.value(), response.getStatusCode()); assertEquals(book.getTitle(), response.jsonPath() .get("title")); } @Test public void whenGetNotExistBookById_thenNotFound() { Response response = RestAssured.get(API_ROOT + "/" + randomNumeric(4)); assertEquals(HttpStatus.NOT_FOUND.value(), response.getStatusCode()); } @Test public void whenCreateNewBook_thenCreated() { Book book = createRandomBook(); Response response = RestAssured.given() .contentType(MediaType.APPLICATION_JSON_VALUE) .body(book) .post(API_ROOT); assertEquals(HttpStatus.CREATED.value(), response.getStatusCode()); } @Test public void whenInvalidBook_thenError() { Book book = createRandomBook(); book.setAuthor(null); Response response = RestAssured.given() .contentType(MediaType.APPLICATION_JSON_VALUE) .body(book) .post(API_ROOT); assertEquals(HttpStatus.BAD_REQUEST.value(), response.getStatusCode()); } @Test public void whenUpdateCreatedBook_thenUpdated() { Book book = createRandomBook(); String location = createBookAsUri(book); book.setId(Long.parseLong(location.split("api/books/")[1])); book.setAuthor("newAuthor"); Response response = RestAssured.given() .contentType(MediaType.APPLICATION_JSON_VALUE) .body(book) .put(location); assertEquals(HttpStatus.OK.value(), response.getStatusCode()); response = RestAssured.get(location); assertEquals(HttpStatus.OK.value(), response.getStatusCode()); assertEquals("newAuthor", response.jsonPath() .get("author")); } @Test public void whenDeleteCreatedBook_thenOk() { Book book = createRandomBook(); String location = createBookAsUri(book); Response response = RestAssured.delete(location); assertEquals(HttpStatus.OK.value(), response.getStatusCode()); response = RestAssured.get(location); assertEquals(HttpStatus.NOT_FOUND.value(), response.getStatusCode()); } }
写好了测试类，运行就行了。
结论
你的第一个Spring Boot程序就完成了，后面的文章我们会继续丰富和改善这个基本框架，欢迎继续关注。
本文章的例子代码可以参考github： bootstrap-sample-app
