Spring Boot为构建企业应用程序的RESTful Web服务提供了很好的支持,本章将详细说明有关使用Spring Boot构建RESTful Web服务的信息。
如果您是Maven用户,请使用以下代码在您的 pom.xml 文件中添加以下依赖项-
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency>
如果您是Gradle用户,请使用以下代码在您的 build.gradle 文件中添加以下依赖项。
compile('org.springframework.boot:spring-boot-starter-web')
下面给出了完整构建配置文件 Maven构建– pom.xml 的代码-
<?xml version = "1.0" encoding = "UTF-8"?> <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.learnfk</groupId> <artifactId>demo</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>demo</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.8.RELEASE</version> <relativePath/> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <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> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
下面给出了完整构建配置文件 Gradle Build – build.gradle 的代码-
buildscript { ext { springBootVersion = '1.5.8.RELEASE' } repositories { mavenCentral() } dependencies { classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}") } } apply plugin: 'java' apply plugin: 'eclipse' apply plugin: 'org.springframework.boot' group = 'com.learnfk' version = '0.0.1-SNAPSHOT' sourceCompatibility = 1.8 repositories { mavenCentral() } dependencies { compile('org.springframework.boot:spring-boot-starter-web') testCompile('org.springframework.boot:spring-boot-starter-test') }
在继续构建RESTful Web服务之前,建议您了解以下注释-
@RestController批注用于定义RESTful Web服务。它提供JSON,XML和自定义响应。其语法如下所示-
@RestController public class ProductServiceController { }
@RequestMapping批注用于定义请求URI来访问REST方法。默认请求方法是GET。
@RequestMapping(value="/products") public ResponseEntity<Object> getProducts() { }
@RequestBody批注用于定义请求正文内容类型。
public ResponseEntity<Object> createProduct(@RequestBody Product product) { }
@PathVariable批注用于定义自定义或动态请求URI。请求URI中的Path变量定义为大括号{},如下所示-
public ResponseEntity<Object> updateProduct(@PathVariable("id") String id) { }
@RequestParam批注用于从请求URL读取请求参数。默认情况下,它是必需参数。无涯教程还可以为请求参数设置默认值,如下所示:
public ResponseEntity<Object> getProduct( @RequestParam(value="name", required=false, defaultValue="honey") String name) { }
下面显示了定义HTTP GET请求方法的示例代码。在此示例中,使用HashMap来存储产品。请注意使用POJO类作为要存储的产品。
在这里,请求URI为/products ,它将返回HashMap存储库中的产品列表,下面给出了包含GET方法REST Endpoint的控制器类文件。
package com.learnfk.demo.controller; import java.util.HashMap; import java.util.Map; import org.springframework.http.HttpStatus; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import com.learnfk.demo.model.Product; @RestController public class ProductServiceController { private static Map<String, Product> productRepo = new HashMap<>(); static { Product honey = new Product(); honey.setId("1"); honey.setName("Honey"); productRepo.put(honey.getId(), honey); Product almond = new Product(); almond.setId("2"); almond.setName("Almond"); productRepo.put(almond.getId(), almond); } @RequestMapping(value = "/products") public ResponseEntity<Object> getProduct() { return new ResponseEntity<>(productRepo.values(), HttpStatus.OK); } }
以下示例显示了用于定义HTTP POST请求方法的示例代码。在此示例中,使用HashMap来存储产品,其中产品是POJO类。
在这里,请求URI是/products ,在将产品存储到HashMap存储库后,它将返回String字符串。
package com.learnfk.demo.controller; import java.util.HashMap; import java.util.Map; import org.springframework.http.HttpStatus; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController; import com.learnfk.demo.model.Product; @RestController public class ProductServiceController { private static Map<String, Product> productRepo = new HashMap<>(); @RequestMapping(value = "/products", method = RequestMethod.POST) public ResponseEntity<Object> createProduct(@RequestBody Product product) { productRepo.put(product.getId(), product); return new ResponseEntity<>("Product is created successfully", HttpStatus.CREATED); } }
下面给出的示例显示了如何定义HTTP PUT请求方法。在此示例中,使用HashMap来更新现有产品,其中产品是POJO类。
这里的请求URI是/products/{id} ,它将把产品后的String返回到HashMap存储库中。请注意,使用了路径变量 {id} 来定义需要更新的产品ID。
package com.learnfk.demo.controller; import java.util.HashMap; import java.util.Map; import org.springframework.http.HttpStatus; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController; import com.learnfk.demo.model.Product; @RestController public class ProductServiceController { private static Map<String, Product> productRepo = new HashMap<>(); @RequestMapping(value = "/products/{id}", method = RequestMethod.PUT) public ResponseEntity<Object> updateProduct(@PathVariable("id") String id, @RequestBody Product product) { productRepo.remove(id); product.setId(id); productRepo.put(id, product); return new ResponseEntity<>("Product is updated successsfully", HttpStatus.OK); } }
下面给出的示例显示了如何定义HTTP DELETE请求方法。在此示例中,使用HashMap删除了现有产品,即POJO类。
请求URI为/products/{id} ,从HashMap存储库删除产品后,它将返回String。使用了路径变量 {id} ,该变量定义了需要删除的产品ID。
package com.learnfk.demo.controller; import java.util.HashMap; import java.util.Map; import org.springframework.http.HttpStatus; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController; import com.learnfk.demo.model.Product; @RestController public class ProductServiceController { private static Map<String, Product> productRepo = new HashMap<>(); @RequestMapping(value = "/products/{id}", method = RequestMethod.DELETE) public ResponseEntity<Object> delete(@PathVariable("id") String id) { productRepo.remove(id); return new ResponseEntity<>("Product is deleted successsfully", HttpStatus.OK); } }
本节为您提供完整的源代码集。请遵守以下代码以了解其各自的功能-
Spring Boot 主应用类 – DemoApplication.java
package com.learnfk.demo; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class DemoApplication { public static void main(String[] args) { SpringApplication.run(DemoApplication.class, args); } }
POJO类– Product.java
package com.learnfk.demo.model; public class Product { private String id; private String name; public String getId() { return id; } public void setId(String id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } }
Rest Controller 类 – ProductServiceController.java
package com.learnfk.demo.controller; import java.util.HashMap; import java.util.Map; import org.springframework.http.HttpStatus; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController; import com.learnfk.demo.model.Product; @RestController public class ProductServiceController { private static Map<String, Product> productRepo = new HashMap<>(); static { Product honey = new Product(); honey.setId("1"); honey.setName("Honey"); productRepo.put(honey.getId(), honey); Product almond = new Product(); almond.setId("2"); almond.setName("Almond"); productRepo.put(almond.getId(), almond); } @RequestMapping(value = "/products/{id}", method = RequestMethod.DELETE) public ResponseEntity<Object> delete(@PathVariable("id") String id) { productRepo.remove(id); return new ResponseEntity<>("Product is deleted successsfully", HttpStatus.OK); } @RequestMapping(value = "/products/{id}", method = RequestMethod.PUT) public ResponseEntity<Object> updateProduct(@PathVariable("id") String id, @RequestBody Product product) { productRepo.remove(id); product.setId(id); productRepo.put(id, product); return new ResponseEntity<>("Product is updated successsfully", HttpStatus.OK); } @RequestMapping(value = "/products", method = RequestMethod.POST) public ResponseEntity<Object> createProduct(@RequestBody Product product) { productRepo.put(product.getId(), product); return new ResponseEntity<>("Product is created successfully", HttpStatus.CREATED); } @RequestMapping(value = "/products") public ResponseEntity<Object> getProduct() { return new ResponseEntity<>(productRepo.values(), HttpStatus.OK); } }
您可以创建一个可执行的JAR文件,并使用下面的Maven或Gradle命令运行spring boot应用程序,如下所示-
对于Maven,请使用下面显示的命令-
mvn clean install
在" BUILD SUCCESS"之后,您可以在目标目录下找到JAR文件。
对于Gradle,请使用下面显示的命令-
gradle clean build
在" BUILD SUCCESSFUL"之后,您可以在build/libs目录下找到JAR文件。
您可以使用下面显示的命令来运行JAR文件-
java –jar <JARFILE>
这将在Tomcat端口8080上启动应用程序,如下所示-
现在,在POSTMAN应用程序中单击下面显示的URL,然后查看输出。
GET API URL为: http:// localhost:8080/products
POST API URL为: http:// localhost:8080/products
PUT API URL为: http:// localhost:8080/products/3
删除API URL is: http://localhost:8080/products/3
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