spring boot（三）web模块

版权声明：版权没有，盗用不究 https://blog.csdn.net/liman65727/article/details/81949472

前言

这一篇总结一下spring boot中web模块中常用的东西。

构建Restful风格的简单CRUD

Restful风格，现在我还暂时解释不清楚，只能意会。具体参考这篇博客——restful风格介绍

URL	请求类型	接口功能
/users	GET	查询用户列表
/users	POST	创建一个用户
/users/id	GET	根据id查询一个用户
/users/id	PUT	根据id更新一个用户信息
/users/id	DELETE	根据id删除一个用户信息

准备domain对象

package com.learn.springbootresuful.domain;

/**
 * 
 * @author liman
 * @createtime 2018年8月22日
 * @contract 15528212893
 * @comment:
 *
 */
public class User {
	private Long id;
	private String name;
	private Integer age;

	public Long getId() {
		return id;
	}

	public void setId(Long id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Integer getAge() {
		return age;
	}

	public void setAge(Integer age) {
		this.age = age;
	}

}

 完成controller

其中用到的一些注解需要注意的就是@ModelAttribute和@PathVariable即可，第一个是spring mvc中常用的模型视图对象标签。

package com.learn.springbootresuful.web;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.learn.springbootresuful.domain.User;

@RestController
@RequestMapping(value = "/users")
public class UserController {
	
	static Map<Long, User> users = Collections.synchronizedMap(new HashMap<Long, User>());

	@RequestMapping(value = "/", method = RequestMethod.GET)
	public List<User> getUserList() {
		List<User> allUser = new ArrayList<User>(users.values());
		return allUser;
	}

	@RequestMapping(value = "/", method = RequestMethod.POST)
	public String postUser(@ModelAttribute User user) {
		// 处理/users/的post请求
		// 除了@ModelAttribute绑定之外，还可以通过@RequestParam从页面中传参
		users.put(user.getId(), user);
		return "success";
	}

	@RequestMapping(value = "/{id}", method = RequestMethod.GET)
	public User getUser(@PathVariable Long id) {
		return users.get(id);
	}

	@RequestMapping(value = "/{id}", method = RequestMethod.PUT)
	public String putUser(@PathVariable Long id, @ModelAttribute User user) {
		User u = users.get(id);
		u.setName(user.getName());
		u.setAge(user.getAge());
		users.put(id, u);
		return "success";
	}

	@RequestMapping(value = "/{id}", method = RequestMethod.DELETE)
	public String deleteUser(@PathVariable Long id) {
		users.remove(id);
		return "success";
	}
}

controller的测试代码

package com.learn.springbootresuful;

import static org.hamcrest.Matchers.equalTo;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.delete;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.put;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.http.MediaType;
import org.springframework.mock.web.MockServletContext;
import org.springframework.test.context.junit.jupiter.web.SpringJUnitWebConfig;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.WebAppConfiguration;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.RequestBuilder;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;

import com.learn.springbootresuful.web.HelloController;
import com.learn.springbootresuful.web.UserController;

/**
 * 
 * @author liman
 * @createtime 2018年8月22日
 * @contract 15528212893
 * @comment:
 *
 */

@RunWith(SpringJUnit4ClassRunner.class)
@SpringJUnitWebConfig(classes = MockServletContext.class)
@SpringBootConfiguration
@WebAppConfiguration
public class UserControllerTests {

	private MockMvc mvc;

	@Before
	public void setUp() throws Exception {
		mvc = MockMvcBuilders.standaloneSetup(new HelloController(), new UserController()).build();
	}

	/**
	 * 测试获取用户信息列表，应该为空
	 * 
	 * @throws Exception
	 */
	 @Test
	 public void getHello() throws Exception {
	 mvc.perform(MockMvcRequestBuilders.get("/").accept(MediaType.APPLICATION_JSON))
	 .andExpect(status().isOk()).andExpect(status().isOk());
	
	 }
	@Test
	public void testUserController() throws Exception {
		RequestBuilder request = null;
		// 1、get查一下user列表，应该为空
		request = get("/users/");
		mvc.perform(request).andExpect(status().isOk()).andExpect(content().string(equalTo("[]")));

		// 2、post提交一个user
		request = post("/users/").param("id", "1").param("name", "测试大师").param("age", "20");
		mvc.perform(request)
				// .andDo(MockMvcResultHandlers.print())
				.andExpect(content().string(equalTo("success")));

		// 3、get获取user列表，应该有刚才插入的数据
		request = get("/users/");
		mvc.perform(request).andExpect(status().isOk())
				.andExpect(content().string(equalTo("[{\"id\":1,\"name\":\"测试大师\",\"age\":20}]")));

		// 4、put修改id为1的user
		request = put("/users/1").param("name", "测试终极大师").param("age", "30");
		mvc.perform(request).andExpect(content().string(equalTo("success")));

		// 5、get一个id为1的user
		request = get("/users/1");
		mvc.perform(request).andExpect(content().string(equalTo("{\"id\":1,\"name\":\"测试终极大师\",\"age\":30}")));

		// 6、del删除id为1的user
		request = delete("/users/1");
		mvc.perform(request).andExpect(content().string(equalTo("success")));

		// 7、get查一下user列表，应该为空
		request = get("/users/");
		mvc.perform(request).andExpect(status().isOk()).andExpect(content().string(equalTo("[]")));
	}
}

 静态资源的访问（Thymeleaf）

spring boot 中默认的静态资源存放在classpath下

 spring boot提供了一些模板用于渲染html页面常见的有Thymeleaf、FreeMarker、Velocity、Groovy、Mustache。这里对这些也不做详细介绍

引入Thymeleaf 依赖

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

Controller代码

@Controller
@RequestMapping(value="/hello")
public class HelloController {
	
	@RequestMapping("/")
	public String index(ModelMap map) {
		map.addAttribute("host","http://www.baidu.com");
		return "index";
	}
	
}

index.html模板页

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8" />
    <title></title>
</head>
<body>
<h1 th:text="${host}">Hello World</h1>
</body>
</html>

测试结果

全局异常的处理

spring boot中提供了一个默认的异常处理请求/error，如果业务代码中抛出异常了，spring boot会去请求这个路径，然后跳转到spring boot默认的异常页面，这个非常不友好。了解全局的异常处理，另一方面对以后养成良好的开发习惯也有一些帮助。

1、定义统一的异常处理类

@ControllerAdvice
public class GlobalExceptionHandler {
	public static final String DEFAULT_ERROR_VIEW="error";
	
	//这里注解中需要指定异常类型，根据不同的异常，会有不同的处理函数
	@ExceptionHandler(value = Exception.class)
	public ModelAndView defaultErrorHandler(HttpServletRequest request,Exception exception) {
		ModelAndView mav = new ModelAndView();
		mav.addObject("exception",exception);
		mav.addObject("url",request.getRequestURL());
		mav.setViewName(DEFAULT_ERROR_VIEW);
		return mav;
	}
}

@ControllerAdvice定义统一的异常处理类，@ExceptionHandler(value=[异常类型])，上述代码中的DEFAULT_ERROR_VIEW只是错误页面的路径。

2、error.html页面

<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8" />
    <title>异常页面</title>
</head>
<body>
    <h1>Error Handler</h1>
    <div th:text="${url}"></div>
    <div th:text="${exception.message}"></div>
</body>
</html>

3、测试结果

针对如何将错误信息以json格式返回，在做实验的时候出现了异常问题，这个后面会补上

To be continued......（未完待续......） 

集成Swagger2

To be continued ......

总结

其实写到这里，spring boot中常用的web模块的东西都已经做了一个简单的总结了，但是都只是一些helloworld，并没有实际深入。