[bigdata-081] 用spring实现一个json返回值的api并部署到tomcat

1. 用eclipse创建一个maven项目

2. 目录结构如下

.
├── pom.xml
├── src
│ ? ├── main
│ ? │ ? ├── java
│ ? │ ? │ ? └── com
│ ? │ ? │ ? ? ? └── tts
│ ? │ ? │ ? ? ? ? ? └── demo
│ ? │ ? │ ? ? ? ? ? ? ? └── restdemo
│ ? │ ? │ ? ? ? ? ? ? ? ? ? ├── App.java
│ ? │ ? │ ? ? ? ? ? ? ? ? ? ├── GreetingController.java
│ ? │ ? │ ? ? ? ? ? ? ? ? ? └── Greeting.java
│ ? │ ? └── webapp

3. pom.xml文件内容如下

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.tts.demo</groupId>
  <artifactId>restdemo</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>restdemo</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <java.version>1.8</java.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <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>
    <dependency>
    	<groupId>com.jayway.jsonpath</groupId>
    	<artifactId>json-path</artifactId>
    	<scope>test</scope>
    </dependency>
    <dependency>
    	<groupId>org.springframework.boot</groupId>
    	<artifactId>spring-boot-starter-tomcat</artifactId>
    	<scope>provided</scope>
    </dependency>
  </dependencies>
  <parent>
  	<groupId>org.springframework.boot</groupId>
  	<artifactId>spring-boot-starter-parent</artifactId>
  	<version>1.5.2.RELEASE</version>
  </parent>
  <build>
  	<plugins>
  		<plugin>
  			<groupId>org.springframework.boot</groupId>
  			<artifactId>spring-boot-maven-plugin</artifactId>
  		</plugin>
  	</plugins>
  </build>
</project>

4.?App.java

package com.tts.demo.restdemo;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.support.SpringBootServletInitializer;  

@SpringBootApplication
public class App extends SpringBootServletInitializer{
	
	@Override
	protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
		// 注意这里要指向原先用main方法执行的Application启动类
		return builder.sources(App.class);
	}
	
}

package com.tts.demo.restdemo;

public class Greeting {
	
	private final long id;
    private final String content;

    public Greeting(long id,String content) {
        this.id = id;
        this.content = content;
    }

    public long getId() {
        return id;
    }

    public String getContent() {
        return content;
    }

}

package com.tts.demo.restdemo;

import java.util.concurrent.atomic.AtomicLong;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class GreetingController {

	private static final String template = "Hello,%s!";
    private final AtomicLong counter = new AtomicLong();

    @RequestMapping("/greeting")
    public Greeting greeting(@RequestParam(value="name",defaultValue="World") String name) {
        return new Greeting(counter.incrementAndGet(),String.format(template,name));
    }
    
}

7. 在项目上点击右键，执行export成war包，比如xx.war

8. 本地测试：启动tomcat; 将xx.war放入到tomcat的webapps目录。

9. 在浏览器地址栏输入 https://localhost:8080/xx/greeting

能看到json字符串，形如

{"id":5,"content":"Hello,World!"}