【Spring】SpringMVC之REST编程风格

REST架构是一个抽象的概念，目前主要是基于HTTP协议实现，其目的是为了提高系统的可伸缩性、降低应用之间的耦合度、便于架构分布式处理程序。当使用多种语言进行开发的时候，每一种语言对URL的处理不同，这时候就需要统一处理，那么使用REST编程风格就很有必要了。REST只是一种设计模式，如果需要对安全性有要求，就是额外的功能代码了。

使用方式

在URL中设置使用如下方式: /{变量名1}/{变量名2}

在代码中向Controller方法注入参数:  (@PathVariable("变量名1") String str1,@PathVariable("变量名2") String str2) 
例如：

        @RequestMapping(value="/book/{bookid}",method=RequestMethod.POST)
        @ResponseBody
        public Object getBook(@PathVariable("bookid") String bookid){

            return new Book();
        }

Demo

bean类：

package cn.xdl.bean;

public class Book {

    private int bid;
    private String bname;
    public int getBid() {
        return bid;
    }
    public void setBid(int bid) {
        this.bid = bid;
    }
    public String getBname() {
        return bname;
    }
    public void setBname(String bname) {
        this.bname = bname;
    }
    public Book(int bid, String bname) {
        super();
        this.bid = bid;
        this.bname = bname;
    }
    public Book() {
        super();
        // TODO Auto-generated constructor stub
    }
    @Override
    public String toString() {
        return "Book [bid=" + bid + ", bname=" + bname + "]";
    }
    
}

Controller类：

package cn.xdl.c;

import java.util.HashMap;
import java.util.Map;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import cn.xdl.bean.Book;

@Controller
public class BookController {

    /**
     * VALUE :请求的地址模版 (模版中使用大括号括住的部分, 属于变量)
     * method: 请求的方式
     * @return
     */
    @RequestMapping(value="/book/{bookid}",method=RequestMethod.GET)
    @ResponseBody
    public Object insertBook(@PathVariable("bookid") String bookId) {
        System.out.println("正在查询图书 , 请求的图书的编号为:"+bookId);
        return new Book(Integer.parseInt(bookId), "欢乐颂");
    }
    @RequestMapping(value="book/{bookid}",method=RequestMethod.DELETE)
    @ResponseBody
    public Object deleteBook(@PathVariable("bookid")String bookid) {
        System.out.println("正在删除图书:id:"+bookid);
        Map<String,String> map = new HashMap<String,String>();
        map.put("errorCode0", "0");
        map.put("msg", "删除成功");
        return map;
    }
    @RequestMapping(value="book/{bookid}/{bookname}",method=RequestMethod.PUT)
    @ResponseBody
    public Object updateBook(@PathVariable("bookid") String bookId,@PathVariable("bookname") String bookName) {
        System.out.println("正在修改图书:id:"+bookId+", 要修改的新书名:"+bookName);
        Map<String,String> map = new HashMap<String,String>();
        map.put("errorCode0", "0");
        map.put("msg", "修改成功");
        return map;
    }
    
    @RequestMapping(value="book/{bookid}/{bookname}",method=RequestMethod.POST)
    @ResponseBody
    public Object insertBook(@PathVariable("bookid") String bookId,@PathVariable("bookname") String bookName) {
        System.out.println("正在添加图书:id:"+bookId+", 要添加的新书名:"+bookName);
        Map<String,String> map = new HashMap<String,String>();
        map.put("errorCode0", "0");
        map.put("msg", "添加成功");
        return map;
    }
    
    
}

这里的通信方式返回的结果是Object对象。在这个笔者使用了注解 @ResponseBody ，需要导入包 jackson-annotations.jar 、 jackson-core.jar 和 jackson-databind.jar包。

bean.xml文件

<?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:jdbc="http://www.springframework.org/schema/jdbc"  
    xmlns:jee="http://www.springframework.org/schema/jee" 
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:aop="http://www.springframework.org/schema/aop" 
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:util="http://www.springframework.org/schema/util"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-4.1.xsd
        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-4.1.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.1.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.1.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.1.xsd">
        <!-- 
            开启注解扫描
         -->
         <context:component-scan base-package="cn"></context:component-scan>
         <!-- 
             开启mvc注解扫描
          -->
        <mvc:annotation-driven/>
        
        <mvc:default-servlet-handler/>
        
        
</beans>

在配置文件中一定需要指出：

<mvc:default-servlet-handler/>

否则会出现静态资源（如js、css等资源）拦截404的错误。

web.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">

    <servlet>
        <servlet-name>webmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:bean.xml</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>webmvc</servlet-name>
        <url-pattern>/</url-pattern>
        
    </servlet-mapping>


</web-app>

web.xml文件过滤的url必须写成 <url-pattern>/</url-pattern> ,因为采用REST编程风格，在url地址中只会出现/分割符号，所以只能写成这样 <url-pattern>/</url-pattern> ，以匹配所有的路径。

restTest.jsp文件

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript">
    function insertClick(){
        $.ajax({
            url:"book/10003/hahaha",
            dataType:"JSON",
            type:"POST",
            success:function(data){
                alert( JSON.stringify(data));
            },
            error:function(){
                
            }
        });
        
    }
    function deleteClick(){
        $.ajax({
            url:"book/10003",
            dataType:"JSON",
            type:"DELETE",
            success:function(data){
                alert( JSON.stringify(data));
            },
            error:function(){
                
            }
        });
        
        
    }
    function updateClick(){
        $.ajax({
            url:"book/10003/hahaha",
            dataType:"JSON",
            type:"PUT",
            success:function(data){
                alert( JSON.stringify(data));
            },
            error:function(){
                
            }
        });
        
    }
    function findClick(){
        $.ajax({
            url:"book/10003",
            dataType:"JSON",
            type:"GET",
            success:function(data){
                alert( JSON.stringify(data));
            },
            error:function(){
                
            }
        });
        
    }

</script>
</head>
<body>
    <input onclick="insertClick()" type="button" value="增加"/><br><br>
    <input onclick="deleteClick()" type="button" value="删除"/><br><br>
    <input onclick="updateClick()" type="button" value="修改"/><br><br>
    <input onclick="findClick()" type="button" value="查询"/><br><br>
</body>
</html>

这里通信方式是采用Ajax请求。

Rest请求地址中带有中文的处理

如果在Rest风格的请求中，请求的参数带有中文，就会出现映射错误。这时候需要进行如下的配置：

在SpringMVC的配置文件中将 <mvc:annotation-driven/> 改为：

<!--开始注解-->
    <mvc:annotation-driven>  
        <mvc:message-converters>  
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">  
                <property name="supportedMediaTypes">  
                    <list>  
                        <value>text/html;charset=UTF-8</value>  
                    </list>  
                </property>  
            </bean>  
        </mvc:message-converters>  
    </mvc:annotation-driven>

除此之外还需要在tomcat 的 server.xml中，加入URIEncoding="UTF-8":

    <Connector connectionTimeout="20000" port="8081" URIEncoding="UTF-8" protocol="HTTP/1.1" redirectPort="8443"/>

这样就可以解决Rest请求中中文乱码的问题了。