在前面的快速入門教程中，我們利用5分鐘構建了一個非常簡單的RESTful Webservice，現在我們來利用Spring Boot來構建一個復雜一點的RestFul API。

關于RESTful API如何設計，大家可以自行去阮一峰的博客學習一下。話說阮老師真是一個全才，感覺他都懂，程序猿楷模啊！

我們來設計一個Book的RESTful API，如下所示：

Book的實體類定義如下：

public class Book {

    private Long bookId;
    private String title;
    private String author;

    //getter/setter方法省略
}

針對Book資源操作的RESTful接口實現如下：

@RestController
@RequestMapping(value="/books")
public class BookController {

    // 創建線程安全的Map
    static Map<Long, Book> books = Collections.synchronizedMap(new HashMap<Long, Book>());

    @RequestMapping(value="/", method= RequestMethod.GET)
    public List<Book> getUserList() {
        // 處理"/books/"的GET請求，用來獲取圖書列表
        // 還可以通過@RequestParam傳遞參數來進行查詢條件或者翻頁信息的傳遞
        List<Book> r = new ArrayList<Book>(books.values());
        return r;
    }

    @RequestMapping(value="/", method=RequestMethod.POST,produces = "application/json")
    public String createBook(@RequestBody Book book) {
        // 處理"/books/"的POST請求，用來創建User
        // 除了@ModelAttribute綁定參數之外，還可以通過@RequestParam從頁面中傳遞參數
        books.put(book.getBookId(), book);
        return "success";
    }

    @RequestMapping(value="/{bookId}", method=RequestMethod.GET)
    public Book getBook(@PathVariable Long bookId) {
        // 處理"/books/{id}"的GET請求，用來獲取url中id值的Book信息
        // url中的id可通過@PathVariable綁定到函數的參數中
        return books.get(bookId);
    }

    @RequestMapping(value="/{bookId}", method=RequestMethod.PUT)
    public String putBook(@PathVariable Long bookId, @RequestBody Book book) {
        // 處理"/books/{bookId}"的PUT請求，用來更新Book信息
        Book b = books.get(bookId);
        b.setTitile(book.getTitile());
        b.setAuthor(book.getAuthor());
        books.put(bookId, b);
        return "success";
    }

    @RequestMapping(value="/{bookId}", method=RequestMethod.DELETE)
    public String deleteBook(@PathVariable Long bookId) {
        // 處理"/books/{bookId}"的DELETE請求，用來刪除Book
        books.remove(bookId);
        return "success";
    }
}

單元測試

之前我們在入門教程中使用了Postman來進行測試，現在我們使用Spring自家的MockMvc框架來寫單元測試，MockMvc的使用很簡單，更詳細的用法大家可以自行Google或百度。

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = MockServletContext.class)
@WebAppConfiguration
public class TestBookController {

    private MockMvc mvc;

    private RequestBuilder request = null;


    @Before
    public void setUp() throws Exception {
        mvc = MockMvcBuilders.standaloneSetup(new BookController()).build();
        request = null;
    }

    public void testGet() throws Exception{
        request = get("/books/");
        mvc.perform(request)
                .andExpect(status().isOk())
                .andExpect(content().string(equalTo("[]")));
    }

    public void testPost() throws Exception{
        Book book = new Book();
        book.setBookId(Long.parseLong("1"));
        book.setTitile("Spring Boot Tutorial");
        book.setAuthor("bluecoffee");
        ObjectMapper objectMapper = new ObjectMapper();
        String jsonBook = objectMapper.writeValueAsString(book);

        request = post("/books/")
                .contentType(MediaType.APPLICATION_JSON)
                .content(jsonBook.getBytes());

        mvc.perform(request)
                .andExpect(status().isOk())
                .andExpect(content().string(equalTo("success")));

        String respStr = mvc.perform(get("/books/"))
                .andExpect(status().isOk())
                .andExpect(content().string(equalTo("[" + jsonBook + "]")))
                .andReturn().getResponse().getContentAsString();
        System.out.println("testPost.resp:"+respStr);
    }

    public void testPut() throws Exception{
        Book book = new Book();
        book.setBookId(Long.parseLong("1"));
        book.setTitile("Spring Boot學習教程");
        book.setAuthor("Alex Qian");
        ObjectMapper objectMapper = new ObjectMapper();
        String jsonBook = objectMapper.writeValueAsString(book);

        request = put("/books/" + book.getBookId())
                .contentType(MediaType.APPLICATION_JSON)
                .content(jsonBook.getBytes());

        mvc.perform(request)
                .andExpect(status().isOk())
                .andExpect(content().string(equalTo("success")));

        String respStr = mvc.perform(get("/books/"+book.getBookId()))
                .andExpect(status().isOk())
                .andExpect(content().string(equalTo(jsonBook)))
                .andReturn().getResponse().getContentAsString();
        System.out.println("testPut.resp:"+respStr);
    }

    public void testDelete() throws Exception{
        request = delete("/books/1");
        mvc.perform(request)
                .andExpect(status().isOk())
                .andExpect(content().string(equalTo("success")));

        String respStr = mvc.perform(get("/books/"))
                .andExpect(status().isOk())
                .andExpect(content().string(equalTo("[]")))
                .andReturn().getResponse().getContentAsString();
        System.out.println("testDelete.resp:"+respStr);

    }

    @Test
    public void testSuite() throws Exception{
        this.testGet();//獲取一本書籍
        this.testPost();//創建一本書籍
        this.testPut();//更新一本書籍
        this.testDelete();//刪除一本書籍
    }
}

小結

在這次教程里面，我們僅引入Spring Boot的web模塊，并且沒有引入任何配置文件，就構建了一個較完整的RESTful API，文中還簡要介紹了@PathVariable,@RequestBody,@RequestParam等參數綁定注解的用法，更多的用法大家可以自行去網上查詢資料。

完整代碼戳這里: Chapter 3-1-1 - 構建復雜RESTful API及單元測試