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【本系列其他教程正在陆续翻译中,点击分类:spring 4 mvc 进行查看。源码下载地址在文章末尾。】
【翻译 by 明明如月 QQ 605283073】
原文地址:http://websystique.com/springmvc/spring-mvc-4-restful-web-services-crud-example-resttemplate/上一篇:
本文非常好,推荐大家好好看看,很多人理解的restful不对
本文我们将使用Spring
MVC 4实现 CRUD Restful WebService , 通过RestTemplate写一个 REST 客户端,定义这些服务. 我们也可以通过外部的一些客户端来测试这些服务。
它是可以用来设计web services的框架,可以被不同的客户端调用。
核心思想是:使用简单的HTTP协议来实现调用,而不是CORBA, RPC 或者 SOAP等负责的机制。
在Rest 基础设计中,资源使用以下动词进行操作。
尽管没有限制必须返回的类型,但是一般基于Web services的Rest返回JSON或者XML作为响应。
客户端可以指定(使用HTTP Accept header)他们想要的资源类型吗,服务器返回需要的资源。
指明资源的Content-Type。如果想详细的理解 restful可以参考这里:StackOverflow link
我们的 REST API :
package com.websystique.springmvc.controller;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
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 org.springframework.web.util.UriComponentsBuilder;
import com.websystique.springmvc.model.User;
import com.websystique.springmvc.service.UserService;
@RestController
public class HelloWorldRestController {
@Autowired
UserService userService; //Service which will do all data retrieval/manipulation work
//-------------------Retrieve All Users--------------------------------------------------------
@RequestMapping(value = "/user/", method = RequestMethod.GET)
public ResponseEntity<List<User>> listAllUsers() {
List<User> users = userService.findAllUsers();
if(users.isEmpty()){
return new ResponseEntity<List<User>>(HttpStatus.NO_CONTENT);//You many decide to return HttpStatus.NOT_FOUND
}
return new ResponseEntity<List<User>>(users, HttpStatus.OK);
}
//-------------------Retrieve Single User--------------------------------------------------------
@RequestMapping(value = "/user/{id}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<User> getUser(@PathVariable("id") long id) {
System.out.println("Fetching User with id " + id);
User user = userService.findById(id);
if (user == null) {
System.out.println("User with id " + id + " not found");
return new ResponseEntity<User>(HttpStatus.NOT_FOUND);
}
return new ResponseEntity<User>(user, HttpStatus.OK);
}
//-------------------Create a User--------------------------------------------------------
@RequestMapping(value = "/user/", method = RequestMethod.POST)
public ResponseEntity<Void> createUser(@RequestBody User user, UriComponentsBuilder ucBuilder) {
System.out.println("Creating User " + user.getName());
if (userService.isUserExist(user)) {
System.out.println("A User with name " + user.getName() + " already exist");
return new ResponseEntity<Void>(HttpStatus.CONFLICT);
}
userService.saveUser(user);
HttpHeaders headers = new HttpHeaders();
headers.setLocation(ucBuilder.path("/user/{id}").buildAndExpand(user.getId()).toUri());
return new ResponseEntity<Void>(headers, HttpStatus.CREATED);
}
//------------------- Update a User --------------------------------------------------------
@RequestMapping(value = "/user/{id}", method = RequestMethod.PUT)
public ResponseEntity<User> updateUser(@PathVariable("id") long id, @RequestBody User user) {
System.out.println("Updating User " + id);
User currentUser = userService.findById(id);
if (currentUser==null) {
System.out.println("User with id " + id + " not found");
return new ResponseEntity<User>(HttpStatus.NOT_FOUND);
}
currentUser.setName(user.getName());
currentUser.setAge(user.getAge());
currentUser.setSalary(user.getSalary());
userService.updateUser(currentUser);
return new ResponseEntity<User>(currentUser, HttpStatus.OK);
}
//------------------- Delete a User --------------------------------------------------------
@RequestMapping(value = "/user/{id}", method = RequestMethod.DELETE)
public ResponseEntity<User> deleteUser(@PathVariable("id") long id) {
System.out.println("Fetching & Deleting User with id " + id);
User user = userService.findById(id);
if (user == null) {
System.out.println("Unable to delete. User with id " + id + " not found");
return new ResponseEntity<User>(HttpStatus.NOT_FOUND);
}
userService.deleteUserById(id);
return new ResponseEntity<User>(HttpStatus.NO_CONTENT);
}
//------------------- Delete All Users --------------------------------------------------------
@RequestMapping(value = "/user/", method = RequestMethod.DELETE)
public ResponseEntity<User> deleteAllUsers() {
System.out.println("Deleting All Users");
userService.deleteAllUsers();
return new ResponseEntity<User>(HttpStatus.NO_CONTENT);
}
}@RestController :首先我们使用的是Spring 4的新注解 @RestController注解.
此注解避免了每个方法都要加上@ResponseBody注解。也就是说@RestController 自己戴上了 @ResponseBody注解,看以看作是
@Controller 和 @ResponseBody的结合体。
@RequestBody : 如果方法参数被 @RequestBody注解,Spring将绑定HTTP请求体到那个参数上。如果那样做,Spring将根据请求中的ACCEPT或者 Content-Type header(私下)使用 HTTP Message converters 来将http请求体转化为domain对象。
@ResponseBody : 如果方法加上了@ResponseBody注解,Spring返回值到响应体。如果这样做的话,Spring将根据请求中的 Content-Type header(私下)使用 HTTP Message converters 来将domain对象转换为响应体。
ResponseEntity 是一个真实数据.它代表了整个 HTTP 响应(response). 它的好处是你可以控制任何对象放到它内部。
你可以指定状态码、头信息和响应体。它包含你想要构建HTTP Response 的信息。
@PathVariable 此注解意味着一个方法参数应该绑定到一个url模板变量[在‘{}‘里的一个]中
一般来说你,要实现REST API in Spring 4 需要了解@RestController , @RequestBody, ResponseEntity 和 @PathVariable 这些注解 .另外, spring 也提供了一些支持类帮助你实现一些可定制化的东西。
MediaType : 带着 @RequestMapping 注解,通过特殊的控制器方法你可以额外指定,MediaType来生产或者消耗。
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.5.3</version>
</dependencyRestTemplate随之出现。RestTemplate
提供了高级方法,来响应者6种主要的HTTP方法。
HTTP
方法和对应的 RestTemplate方法:
package com.websystique.springmvc;
import java.net.URI;
import java.util.LinkedHashMap;
import java.util.List;
import org.springframework.web.client.RestTemplate;
import com.websystique.springmvc.model.User;
public class SpringRestTestClient {
public static final String REST_SERVICE_URI = "http://localhost:8080/Spring4MVCCRUDRestService";
/* GET */
@SuppressWarnings("unchecked")
private static void listAllUsers(){
System.out.println("Testing listAllUsers API-----------");
RestTemplate restTemplate = new RestTemplate();
List<LinkedHashMap<String, Object>> usersMap = restTemplate.getForObject(REST_SERVICE_URI+"/user/", List.class);
if(usersMap!=null){
for(LinkedHashMap<String, Object> map : usersMap){
System.out.println("User : id="+map.get("id")+", Name="+map.get("name")+", Age="+map.get("age")+", Salary="+map.get("salary"));;
}
}else{
System.out.println("No user exist----------");
}
}
/* GET */
private static void getUser(){
System.out.println("Testing getUser API----------");
RestTemplate restTemplate = new RestTemplate();
User user = restTemplate.getForObject(REST_SERVICE_URI+"/user/1", User.class);
System.out.println(user);
}
/* POST */
private static void createUser() {
System.out.println("Testing create User API----------");
RestTemplate restTemplate = new RestTemplate();
User user = new User(0,"Sarah",51,134);
URI uri = restTemplate.postForLocation(REST_SERVICE_URI+"/user/", user, User.class);
System.out.println("Location : "+uri.toASCIIString());
}
/* PUT */
private static void updateUser() {
System.out.println("Testing update User API----------");
RestTemplate restTemplate = new RestTemplate();
User user = new User(1,"Tomy",33, 70000);
restTemplate.put(REST_SERVICE_URI+"/user/1", user);
System.out.println(user);
}
/* DELETE */
private static void deleteUser() {
System.out.println("Testing delete User API----------");
RestTemplate restTemplate = new RestTemplate();
restTemplate.delete(REST_SERVICE_URI+"/user/3");
}
/* DELETE */
private static void deleteAllUsers() {
System.out.println("Testing all delete Users API----------");
RestTemplate restTemplate = new RestTemplate();
restTemplate.delete(REST_SERVICE_URI+"/user/");
}
public static void main(String args[]){
listAllUsers();
getUser();
createUser();
listAllUsers();
updateUser();
listAllUsers();
deleteUser();
listAllUsers();
deleteAllUsers();
listAllUsers();
}
}Testing listAllUsers API----------- User : id=1, Name=Sam, Age=30, Salary=70000.0 User : id=2, Name=Tom, Age=40, Salary=50000.0 User : id=3, Name=Jerome, Age=45, Salary=30000.0 User : id=4, Name=Silvia, Age=50, Salary=40000.0 Testing getUser API---------- User [id=1, name=Sam, age=30, salary=70000.0] Testing create User API---------- Location : http://localhost:8080/Spring4MVCCRUDRestService/user/5 Testing listAllUsers API----------- User : id=1, Name=Sam, Age=30, Salary=70000.0 User : id=2, Name=Tom, Age=40, Salary=50000.0 User : id=3, Name=Jerome, Age=45, Salary=30000.0 User : id=4, Name=Silvia, Age=50, Salary=40000.0 User : id=5, Name=Sarah, Age=51, Salary=134.0 Testing update User API---------- User [id=1, name=Tomy, age=33, salary=70000.0] Testing listAllUsers API----------- User : id=1, Name=Tomy, Age=33, Salary=70000.0 User : id=2, Name=Tom, Age=40, Salary=50000.0 User : id=3, Name=Jerome, Age=45, Salary=30000.0 User : id=4, Name=Silvia, Age=50, Salary=40000.0 User : id=5, Name=Sarah, Age=51, Salary=134.0 Testing delete User API---------- Testing listAllUsers API----------- User : id=1, Name=Tomy, Age=33, Salary=70000.0 User : id=2, Name=Tom, Age=40, Salary=50000.0 User : id=4, Name=Silvia, Age=50, Salary=40000.0 User : id=5, Name=Sarah, Age=51, Salary=134.0 Testing all delete Users API---------- Testing listAllUsers API----------- No user exist----------
<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.websystique.springmvc</groupId>
<artifactId>Spring4MVCCRUDRestService</artifactId>
<packaging>war</packaging>
<version>1.0.0</version>
<name>Spring4MVCCRUDRestService Maven Webapp</name>
<properties>
<springframework.version>4.2.0.RELEASE</springframework.version>
<jackson.version>2.5.3</jackson.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${springframework.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>${springframework.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
</dependencies>
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.2</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.4</version>
<configuration>
<warSourceDirectory>src/main/webapp</warSourceDirectory>
<warName>Spring4MVCCRUDRestService</warName>
<failOnMissingWebXml>false</failOnMissingWebXml>
</configuration>
</plugin>
</plugins>
</pluginManagement>
<finalName>Spring4MVCCRUDRestService</finalName>
</build>
</project>package com.websystique.springmvc.service;
import java.util.List;
import com.websystique.springmvc.model.User;
public interface UserService {
User findById(long id);
User findByName(String name);
void saveUser(User user);
void updateUser(User user);
void deleteUserById(long id);
List<User> findAllUsers();
void deleteAllUsers();
public boolean isUserExist(User user);
}package com.websystique.springmvc.service;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.atomic.AtomicLong;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.websystique.springmvc.model.User;
@Service("userService")
@Transactional
public class UserServiceImpl implements UserService{
private static final AtomicLong counter = new AtomicLong();
private static List<User> users;
static{
users= populateDummyUsers();
}
public List<User> findAllUsers() {
return users;
}
public User findById(long id) {
for(User user : users){
if(user.getId() == id){
return user;
}
}
return null;
}
public User findByName(String name) {
for(User user : users){
if(user.getName().equalsIgnoreCase(name)){
return user;
}
}
return null;
}
public void saveUser(User user) {
user.setId(counter.incrementAndGet());
users.add(user);
}
public void updateUser(User user) {
int index = users.indexOf(user);
users.set(index, user);
}
public void deleteUserById(long id) {
for (Iterator<User> iterator = users.iterator(); iterator.hasNext(); ) {
User user = iterator.next();
if (user.getId() == id) {
iterator.remove();
}
}
}
public boolean isUserExist(User user) {
return findByName(user.getName())!=null;
}
private static List<User> populateDummyUsers(){
List<User> users = new ArrayList<User>();
users.add(new User(counter.incrementAndGet(),"Sam",30, 70000));
users.add(new User(counter.incrementAndGet(),"Tom",40, 50000));
users.add(new User(counter.incrementAndGet(),"Jerome",45, 30000));
users.add(new User(counter.incrementAndGet(),"Silvia",50, 40000));
return users;
}
public void deleteAllUsers() {
users.clear();
}
}package com.websystique.springmvc.model;
public class User {
private long id;
private String name;
private int age;
private double salary;
public User(){
id=0;
}
public User(long id, String name, int age, double salary){
this.id = id;
this.name = name;
this.age = age;
this.salary = salary;
}
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 int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + (int) (id ^ (id >>> 32));
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
User other = (User) obj;
if (id != other.id)
return false;
return true;
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", age=" + age
+ ", salary=" + salary + "]";
}
}package com.websystique.springmvc.configuration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.websystique.springmvc")
public class HelloWorldConfiguration {
}
package com.websystique.springmvc.configuration;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
public class HelloWorldInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
@Override
protected Class<?>[] getRootConfigClasses() {
return new Class[] { HelloWorldConfiguration.class };
}
@Override
protected Class<?>[] getServletConfigClasses() {
return null;
}
@Override
protected String[] getServletMappings() {
return new String[] { "/" };
}
}package com.websystique.springmvc.configuration;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;
public class CORSFilter implements Filter {
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
System.out.println("Filtering on...........................................................");
HttpServletResponse response = (HttpServletResponse) res;
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Allow-Methods", "POST, GET, PUT, OPTIONS, DELETE");
response.setHeader("Access-Control-Max-Age", "3600");
response.setHeader("Access-Control-Allow-Headers", "x-requested-with");
chain.doFilter(req, res);
}
public void init(FilterConfig filterConfig) {}
public void destroy() {}
}package com.websystique.springmvc.configuration;
import javax.servlet.Filter;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
public class HelloWorldInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
@Override
protected Class<?>[] getRootConfigClasses() {
return new Class[] { HelloWorldConfiguration.class };
}
@Override
protected Class<?>[] getServletConfigClasses() {
return null;
}
@Override
protected String[] getServletMappings() {
return new String[] { "/" };
}
@Override
protected Filter[] getServletFilters() {
Filter [] singleton = { new CORSFilter()};
return singleton;
}
}Spring MVC 4 RESTFul Web Services CRUD例子(带源码)【这才是restful,超经典】
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原文地址:http://blog.csdn.net/w605283073/article/details/51338765