Spring Boot简单介绍

Contents

1. 1. Spring: the source for modern java
2. 2. 特点：
3. 3. 快速入门
   1. 3.1. 先决条件
   2. 3.2. 使用maven构建项目
      1. 3.2.1. 1 访问https://start.spring.io/
      2. 3.2.2. 2 选择Maven Project、Spring Boot版本2.0.7选择依赖，这里选择web，可参考下图所示
      3. 3.2.3. 3 点击Generate Project下载demo压缩包
4. 4. 将zip包解压缩导入IntelliJ IDEA中
5. 5. 项目结构解析
6. 6. 添加web模块以及单元测试模块的maven依赖
7. 7. 编写controller
8. 8. 编写单元测试

Spring: the source for modern java

摘自官网https://spring.io/

Spring Boot可以让我们轻松的创建独立的，生产级的应用程序，使程序变得更加轻量化。你可以 “just run”。你可以依靠一个Java的main函数来运行一个Spring应用。你也可以把你的应用打包为一个jar文件，通过java -jar来运行你的Spring程序。大多数Spring Boot应用程序只需要很少的Spring配置。

特点：

• 创建独立的Spring应用程序
• 内嵌Tomcat、Jetty或者Undertow（无需单独部署war文件）
• 开箱即用，提供各种默认配置来简化项目配置
• 没有冗余的代码生成也不需要XML配置
• 尽可能的自动化配置Spring以及第三方库
• 提供生产监控功能，例如metrics（指标）、health checks（运行状况检查）和externalized configuration（外部配置）

快速入门

先决条件

jdk 1.8

spring framework 5.x以上

使用maven构建项目

1 访问https://start.spring.io/

2 选择Maven Project、Spring Boot版本2.0.7选择依赖，这里选择web，可参考下图所示

3 点击Generate Project下载demo压缩包

将zip包解压缩导入IntelliJ IDEA中

项目结构解析

通过上面一系列的操作，我们已经成功的创建了一个Spring Boot程序。Spring Boot的基础结构共三个文件

• src/main/java程序入口：DemoApplicatio
• src/main/resources下的配置文件：application.properties
• src/test/测试入口：DemoApplicationTests

生成的DemoApplicatio和DemoApplicationTests类可以直接运行来启动当前创建的项目，由于目前该项目未配合Web模块，所以程序会在加载完Spring之后结束运行。

添加web模块以及单元测试模块的maven依赖

在pom.xml文件中仅需要引入两个模块就行

• spring-boot-starter-web：核心模块，包括自动配置支持、日志和YAML
• spring-boot-starter-test：测试模块，包括JUnit、Hamcrest、Mockito

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

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

编写controller

• 创建cn.com.bmsmart.controller包
• 创建HelloController类

package cn.com.bmsmart.demo.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * <p>Description: </p>
 * Created by wusong on 2019-01-07 6:55.
 */
@RestController
public class HelloController {

    @GetMapping(value = "/")
    public String sayHello() {
        return "Hello Spring Boot";
    }
}

右键DemoApplication启动main方法，然后打开浏览器，输入http://localhost:8080/可以看到输出了Hello Spring Boot

编写单元测试

打开的工程的src/test/下的测试入口DemoApplicationTests类。然后编写一个单元测试来mock http请求

package cn.com.bmsmart.demo;

import cn.com.bmsmart.demo.controller.HelloController;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.MediaType;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;

import static org.hamcrest.Matchers.equalTo;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = DemoApplication.class)
public class DemoApplicationTests {

    @Autowired
    private HelloController helloController;

    private MockMvc mvc;


    @Before
    public void setUp() throws Exception {
        mvc = MockMvcBuilders.standaloneSetup(helloController).build();
    }

    @Test
    public void contextLoads() throws Exception {
        mvc.perform(MockMvcRequestBuilders.get("/").accept(MediaType.APPLICATION_JSON))
           .andExpect(status().isOk())
           .andExpect(content().string(equalTo("Hello Spring Boot")));
    }

}

通过注入HelloController然后在@Before函数中把mock的对象HelloController传递到MockMvcBuilders.standaloneSetup(helloController).build()中，这样就可以构建我们的单元测试了。

• 注意引入静态类，让status、content、equalTo函数可用

import static org.hamcrest.Matchers.equalTo;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

测试结果

另外一种用法

package cn.com.bmsmart.demo;

import cn.com.bmsmart.demo.controller.HelloController;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.MediaType;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.test.web.servlet.MvcResult;
import org.springframework.test.web.servlet.result.MockMvcResultHandlers;
import org.springframework.test.web.servlet.result.MockMvcResultMatchers;

import static org.hamcrest.Matchers.equalTo;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = DemoApplication.class)
public class DemoApplicationTests {

    @Autowired
    private HelloController helloController;

    private MockMvc mvc;


    @Before
    public void setUp() throws Exception {
        mvc = MockMvcBuilders.standaloneSetup(helloController).build();
    }

    @Test
    public void contextLoads() throws Exception {
//        mvc.perform(MockMvcRequestBuilders.get("/").accept(MediaType.APPLICATION_JSON))
//           .andExpect(status().isOk())
//           .andExpect(content().string(equalTo("Hello Spring Boot")));

        MvcResult mvcResult = mvc.perform(
                MockMvcRequestBuilders.get("/")
                                      .accept(MediaType.APPLICATION_JSON)
        )
                                     .andExpect(MockMvcResultMatchers.status().isOk())
                                     .andDo(MockMvcResultHandlers.print())
                                     .andReturn();
        String content = mvcResult.getResponse().getContentAsString();
        System.out.println(content);
    }
}

测试结果

2019-01-07 07:29:31.555  INFO 7284 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/],methods=[GET]}" onto public java.lang.String cn.com.bmsmart.demo.controller.HelloController.sayHello()
2019-01-07 07:29:31.595  INFO 7284 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.test.web.servlet.setup.StubWebApplicationContext@623ebac7
2019-01-07 07:29:31.616  INFO 7284 --- [           main] o.s.mock.web.MockServletContext          : Initializing Spring FrameworkServlet ''
2019-01-07 07:29:31.616  INFO 7284 --- [           main] o.s.t.web.servlet.TestDispatcherServlet  : FrameworkServlet '': initialization started
2019-01-07 07:29:31.617  INFO 7284 --- [           main] o.s.t.web.servlet.TestDispatcherServlet  : FrameworkServlet '': initialization completed in 1 ms

MockHttpServletRequest:
      HTTP Method = GET
      Request URI = /
       Parameters = {}
          Headers = {Accept=[application/json]}
             Body = <no character encoding set>
    Session Attrs = {}

Handler:
             Type = cn.com.bmsmart.demo.controller.HelloController
           Method = public java.lang.String cn.com.bmsmart.demo.controller.HelloController.sayHello()

Async:
    Async started = false
     Async result = null

Resolved Exception:
             Type = null

ModelAndView:
        View name = null
             View = null
            Model = null

FlashMap:
       Attributes = null

MockHttpServletResponse:
           Status = 200
    Error message = null
          Headers = {Content-Type=[application/json;charset=ISO-8859-1], Content-Length=[17]}
     Content type = application/json;charset=ISO-8859-1
             Body = Hello Spring Boot
    Forwarded URL = null
   Redirected URL = null
          Cookies = []
Hello Spring Boot