使用Spring MVC 4构建Restful服务
使用Spring MVC 4构建RESTful服务相对于其它框架来说,有很多优势。首先,Spring MVC 4作为Spring的框架之一,可以很好地与Spring进行集成。其次,Spring MVC 4的拦截器是在方法层级上的拦截,相对于其它MVC框架(如Struts2)的拦截器具有更高的效率。再者,Spring MVC 4采用基于注解的配置,入手容易,开发灵活。
Spring MVC 4采用的是jacson解析JSON。jacson一款非常高效强大的JSON工具类,可以轻松地在JAVA对象与json对象和XML文档之间进行序列化和反序列化。本文中的例子采用的是Spring 4.1.1.RELEASE和jacson 2.4.0版本,经测试无任何异常。接下来,上干货:
开发环境准备:
Eclipse Luna
Apache Tomcat 8.0
JDK 1.7
Spring 4.1.1.RELEASE
jackson 2.4.0
工程目录如下:
1. 新建Maven Project,选择在“Archetype类型”中,选择“maven-archetype-webapp”。
2. 在Pom.xml中添加 Maven 依赖,从而可以使用 Spring和jackson中的特性。如果读者使用的是Dynamic Web Project,可以从Maven仓库下载对的Spring Jar和 jacson jar。
Spring的Maven仓库地址:http://repo1.maven.org/maven2/org/springframework/
jackson的Maven仓库地址:http://repo1.maven.org/maven2/com/fasterxml/jackson/core/
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< 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.favccxx.favsoft</ groupId >
< artifactId >favspringmvcrestful</ artifactId >
< packaging >war</ packaging >
< version >0.0.1-SNAPSHOT</ version >
< name >favspringmvcrestful Maven Webapp</ name >
< url >http://maven.apache.org</ url >
< properties >
< spring.version >4.1.1.RELEASE</ spring.version >
< jackson.version >2.4.0</ jackson.version >
</ properties >
< dependencies >
< dependency >
< groupId >junit</ groupId >
< artifactId >junit</ artifactId >
< version >3.8.1</ version >
< scope >test</ scope >
</ dependency >
< dependency >
< groupId >org.springframework</ groupId >
< artifactId >spring-core</ artifactId >
< version >${spring.version}</ version >
</ dependency >
< dependency >
< groupId >org.springframework</ groupId >
< artifactId >spring-webmvc</ artifactId >
< version >${spring.version}</ version >
</ dependency >
< dependency >
< groupId >org.springframework</ groupId >
< artifactId >spring-beans</ artifactId >
< version >${spring.version}</ version >
</ dependency >
< dependency >
< groupId >org.springframework</ groupId >
< artifactId >spring-context</ artifactId >
< version >${spring.version}</ version >
</ dependency >
< dependency >
< groupId >com.fasterxml.jackson.core</ groupId >
< artifactId >jackson-core</ artifactId >
< version >${jackson.version}</ version >
</ dependency >
< dependency >
< groupId >com.fasterxml.jackson.core</ groupId >
< artifactId >jackson-annotations</ artifactId >
< version >${jackson.version}</ version >
</ dependency >
< dependency >
< groupId >com.fasterxml.jackson.core</ groupId >
< artifactId >jackson-databind</ artifactId >
< version >${jackson.version}</ version >
</ dependency >
< dependency >
< groupId >jstl</ groupId >
< artifactId >jstl</ artifactId >
< version >1.2</ version >
</ dependency >
< dependency >
< groupId >taglibs</ groupId >
< artifactId >standard</ artifactId >
< version >1.1.2</ version >
</ dependency >
</ dependencies >
< build >
< finalName >favspringmvcrestful</ finalName >
</ build >
</ project >
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3.在 web.xml中,配置Spring MVC 4 的DispatcherServlet转发和编码。
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<? xml version = "1.0" encoding = "UTF-8" ?>
< web-app version = "2.4" xmlns = "http://java.sun.com/xml/ns/j2ee"
xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
< display-name >favblog</ display-name >
< context-param >
< param-name >contextConfigLocation</ param-name >
< param-value ></ param-value >
</ context-param >
< filter >
< filter-name >encodingFilter</ filter-name >
< filter-class >org.springframework.web.filter.CharacterEncodingFilter</ filter-class >
< init-param >
< param-name >encoding</ param-name >
< param-value >UTF-8</ param-value >
</ init-param >
< init-param >
< param-name >forceEncoding</ param-name >
< param-value >true</ param-value >
</ init-param >
</ filter >
< filter-mapping >
< filter-name >encodingFilter</ filter-name >
< url-pattern >/*</ url-pattern >
</ filter-mapping >
< listener >
< listener-class >org.springframework.web.context.ContextLoaderListener</ listener-class >
</ listener >
< servlet >
< servlet-name >springMVC</ servlet-name >
< servlet-class >org.springframework.web.servlet.DispatcherServlet</ servlet-class >
< init-param >
< param-name >contextConfigLocation</ param-name >
< param-value >classpath*:spring-context.xml</ param-value >
</ init-param >
< load-on-startup >1</ load-on-startup >
</ servlet >
< servlet-mapping >
< servlet-name >springMVC</ servlet-name >
< url-pattern >/</ url-pattern >
</ servlet-mapping >
</ web-app >
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<? xml version = "1.0" encoding = "UTF-8" ?>
< beans xmlns = "http://www.springframework.org/schema/beans"
xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
xmlns:context = "http://www.springframework.org/schema/context"
xmlns:mvc = "http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">
< context:component-scan base-package = "com.favccxx.favsoft.favjson.controller" ></ context:component-scan >
< mvc:annotation-driven ></ mvc:annotation-driven >
< bean id = "viewResolver" class = "org.springframework.web.servlet.view.UrlBasedViewResolver" >
< property name = "viewClass"
value = "org.springframework.web.servlet.view.JstlView" />
< property name = "prefix" value = "/WEB-INF/views" />
< property name = "suffix" value = ".jsp" />
</ bean >
</ beans >
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4.新建 FavUser.java 类,测试JSON与Object之间的映射。需要注意的是,如果想对日期进行格式化,在其Getter方法上,使用 @JsonFormat 即可,这样就能输出符合pattern类型的日期,但是这同时也要求输入的日期参数也必须是pattern类型的。
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package com.favccxx.favsoft.favjson.pojo;
import java.util.Date;
import com.fasterxml.jackson.annotation.JsonFormat;
public class FavUser {
private String userId;
private String userName;
private int userAge;
private Date createDate;
public String getUserId() {
return userId;
}
public void setUserId(String userId) {
this .userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this .userName = userName;
}
public int getUserAge() {
return userAge;
}
public void setUserAge( int userAge) {
this .userAge = userAge;
}
@JsonFormat (pattern= "yyyy-MM-dd HH:mm:ss" )
public Date getCreateDate() {
return createDate;
}
public void setCreateDate(Date createDate) {
this .createDate = createDate;
}
} |
5. 新建FavRestfulController,通过不同的方法测试Spring MVC 4 返回String、Object类型的JSON。
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package com.favccxx.favsoft.favjson.controller;
import java.io.IOException;
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.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.favccxx.favsoft.favjson.pojo.FavUser;
@RestController public class FavRestfulController {
@RequestMapping (value= "/getUserName" ,method=RequestMethod.POST)
public String getUserName( @RequestParam (value= "name" ) String name){
return name;
}
@RequestMapping ( "getFavUser" )
public FavUser getFavUser( @RequestParam ( "userName" ) String userName,String userId, int userAge){
FavUser favUser = new FavUser();
favUser.setUserId(userId);
favUser.setUserName(userName);
favUser.setUserAge(userAge);
return favUser;
}
@RequestMapping ( "getFavUserBody" )
public FavUser getFavUserBody( @RequestBody String body){
ObjectMapper mapper = new ObjectMapper();
FavUser favUser = null ;
try {
favUser = mapper.readValue(body, FavUser. class );
} catch (JsonParseException e) {
e.printStackTrace();
} catch (JsonMappingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return favUser;
}
} |
6.运行结果如下: