Spring Boot is a new framework provided by the Pivotal team that is designed to simplify the initial setup and development of new Spring applications. The framework is configured in a way that eliminates the need for developers to define boilerplate configurations. In my words, Spring Boot is not a new framework. It has a default configuration for many frameworks. Just as Maven integrates all jar packages, Spring Boot integrates all frameworks (I don’t know if this metaphor is appropriate).

Said so much, the hand itch is very, immediately to try a round!

• Maven build project

1. Access start.spring. IO /

2, select the build tool Maven Project, Spring Boot version 1.3.6 and some basic Project information, click “Switch to the full version.” Select Java version 1.7, as shown in the following figure:

3. Click Generate Project to download the Project package

Existing Maven Projects -> Next -> Finsh, OK done!

• Introduction to project Structure

As shown in the figure above, the Spring Boot infrastructure consists of three files:

• L SRC /main/ Java program development and main program entry
• L SRC /main/resources configuration file
• L SRC /test/ Java test program

In addition, spingBoot suggests the following directory result:

Root Package structure: com.example.myProject

com +- example +- myproject +- Application.java | +- domain | +- Customer.java | +- CustomerRepository.java | +- service  | +- CustomerService.java | +- controller | +- CustomerController.java |Copy the code

Application. Java is recommended to be placed under the following directory. It is mainly used to do some framework configuration

Domain directory is used for Entity and data access layer.

3. The Service layer is mainly business class code

4. Controller is responsible for page access control

Using the default configuration saves a lot of configuration, but you can also change it as you like

Finally, launch the Application Main method, and a Java project is set up!

• Importing a Web Module

1. Add a web support module to POm. XML:

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
 </dependency> 
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There are two modules in the pom.xml file by default:

Spring-boot-starter: Core module, including automatic configuration support, logging, and YAML;

Spring-boot-starter -test: tests modules, including JUnit, Hamcrest, and Mockito.

2. Write controller content

@RestController public class HelloWorldController { @RequestMapping("/hello") public String index() { return "Hello World"; }}Copy the code

@restController means that all the methods in the controller are output in JSON format, so there is no need to write jackJSON configuration!

3, start the main program, open a browser to http://localhost:8080/hello, you can see the effect, is there a simple!

How to do unit tests

Open the test portal under SRC /test/ and write a simple HTTP request to test; Using mockmvc, using MockMvcResultHandlers. Print () to print out the results.

@RunWith(SpringJUnit4ClassRunner.class) @SpringApplicationConfiguration(classes = MockServletContext.class) @WebAppConfiguration public class HelloWorldControlerTests { private MockMvc mvc; @Before public void setUp() throws Exception { mvc = MockMvcBuilders.standaloneSetup(new HelloWorldController()).build(); } @Test public void getHello() throws Exception { mvc.perform(MockMvcRequestBuilders.get("/hello").accept(MediaType.APPLICATION_JSON)) .andExpect(MockMvcResultMatchers.status().isOk()) .andDo(MockMvcResultHandlers.print()) .andReturn(); }}Copy the code

Debug the development environment

Hot start is very common in normal development projects, although during the development of web projects, changes to the project start and restart always report errors; However, springBoot has good debugging support and changes can take effect in real time. You need to add the following configuration:

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <optional>true</optional>
   </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
                <fork>true</fork>
            </configuration>
        </plugin>
   </plugins>
</build> 
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This module is disabled when running in a fully packaged environment. If you start your application with a Java-jar or with a specific Classloader, it will consider it a “production environment.”