Spring Boot-构建一个复杂的RESTful API及单元测试

在前面的快速入门教程中，我们利用5分钟构建了一个非常简单的RESTful Webservice，现在我们来利用Spring Boot来构建一个复杂一点的RestFul API。

关于RESTful API如何设计，大家可以自行去阮一峰的博客学习一下。话说阮老师真是一个全才，感觉他都懂，程序猿楷模啊！

我们来设计一个Book的RESTful API，如下所示：

请求类型	URL	功能说明
GET	/books	查询书籍列表
POST	/books	创建书籍
GET	/books/id	根据ID查询一本书籍
PUT	/books/id	根据ID更新一本书籍
DELETE	/books/id	根据ID删除一本书籍

##Book的实体类定义如下：

public class Book {

private Long bookId;
private String titile;
private String author;

//getter/setter方法省略
}

##针对Book资源操作的RESTful接口实现如下：

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

// 创建线程安全的Map
static Map<Long, Book> books = Collections.synchronizedMap(new HashMap<Long, Book>());

@RequestMapping(value="/", method= RequestMethod.GET)
public List<Book> getUserList() {
// 处理"/books/"的GET请求，用来获取图书列表
// 还可以通过@RequestParam传递参数来进行查询条件或者翻页信息的传递
List<Book> r = new ArrayList<Book>(books.values());
return r;
}

@RequestMapping(value="/", method=RequestMethod.POST,produces = "application/json")
public String createBook(@RequestBody Book book) {
// 处理"/books/"的POST请求，用来创建User
// 除了@ModelAttribute绑定参数之外，还可以通过@RequestParam从页面中传递参数
books.put(book.getBookId(), book);
return "success";
}

@RequestMapping(value="/{bookId}", method=RequestMethod.GET)
public Book getBook(@PathVariable Long bookId) {
// 处理"/books/{id}"的GET请求，用来获取url中id值的Book信息
// url中的id可通过@PathVariable绑定到函数的参数中
return books.get(bookId);
}

@RequestMapping(value="/{bookId}", method=RequestMethod.PUT)
public String putBook(@PathVariable Long bookId, @RequestBody Book book) {
// 处理"/books/{bookId}"的PUT请求，用来更新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) {
// 处理"/books/{bookId}"的DELETE请求，用来删除Book
books.remove(bookId);
return "success";
}
}

##单元测试
之前我们在入门教程中使用了Postman来进行测试，现在我们使用Spring自家的MockMvc框架来写单元测试，MockMvc的使用很简单，更详细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学习教程");
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();//获取一本书籍
this.testPost();//创建一本书籍
this.testPut();//更新一本书籍
this.testDelete();//删除一本书籍
}
}

##小结
在这次教程里面，我们仅引入Spring Boot的web模块，并且没有引入任何配置文件，就构建了一个较完整的RESTful API，文中还简要介绍了@PathVariable,@RequestBody,@RequestParam等参数绑定注解的用法，更多的用法大家可以自行去网上查询资料。

完整代码戳这里: Chapter 3-1-1 - 构建复杂RESTful API及单元测试