SpringMVC传值

谁借莪１个温暖的怀抱￠ 2022-08-20 10:27 195阅读 0赞

# SpringMVC传值 #

--------------------

## 1 地址栏传值 ##

### **URI Template Patterns**使用@PathVariable ###

将需要传递的数据写在URI 中。

在Spring MVC中

*  首先，通过@RequestMapping表明变量所在URI 的位置和变量名称，像这样
    
        @RequestMapping(path="/owners/{ownerId}", method=RequestMethod.GET)
    
    表明/owners/后面的路径将会别当作变量获取到，变量名称为ownerId
 *  其次，需要使用@PathVariable注解来从uri中的获取变量。像这样
    
    @PathVariable String ownerId

代码如下

@Controller
        @RequestMapping("/mvctest")
        public class MVCController { 
            @RequestMapping(path="/owners/{ownerId}", method=RequestMethod.GET)
                public @ResponseBody String findOwner(@PathVariable String ownerId) {
                    return ownerId;
                }
            }

还有一种写法就是指明变量名称

@PathVariable("ownerId") String ownerId

上面之所以没有指明是因为 Spring MVC 是按照名字匹配的，只要名称一致就可以匹配到。

将数据获取到并直接输出

![这里写图片描述][20160223091504163]

### **@PathVariable续**  ###

A method can have any number of @PathVariable annotations:

*  在方法上可以有很多@PathVariable注解

@RequestMapping(path="/owners/{ownerId}/pets/{petId}", method=RequestMethod.GET)
        public String findPet(@PathVariable String ownerId, @PathVariable String petId, Model model) {
            Owner owner = ownerService.findOwner(ownerId);
            Pet pet = owner.getPet(petId);
            model.addAttribute("pet", pet);
            return "displayPet";
        }

*  还可以获取类上声明的变量
    
    路径：/owners/42/pets/21

@Controller
        @RequestMapping("/owners/{ownerId}")
        public class RelativePathUriTemplateController { 
            @RequestMapping("/pets/{petId}")
            public void findPet(@PathVariable String ownerId, @PathVariable String petId, Model model) {
                // implementation omitted
            }
    
        }

*  还可以使用正则表达式
    
    语法：\{varName:regex\}
    
    路径：/spring-web/spring-web-3.0.5.jar

@RequestMapping("/spring-web/{symbolicName:[a-z-]+}-{version:\\d\\.\\d\\.\\d}{extension:\\.[a-z]+}")
        public void handle(@PathVariable String version, @PathVariable String extension) {
            // ...
        }
    }

*  通配符也可以
    
    /owners/\*/pets/\{petId\}

### **Matrix Variables** 使用@MatrixVariable ###

> In the MVC namespace, the element has an enable-matrix-variables attribute that should be set to true. By default it is set to false.

要使用@MatrixVariable首先需要将配置文件中的

<mvc:annotation-driven />

改为

<mvc:annotation-driven enable-matrix-variables="true" />

@MatrixVariable可以获取到路径中

/cars;color=red;year=2012

color和year的值  
其中color和year也可以是数组

color=red,green,blue

示例：

@RequestMapping(path = "/pets/{petId}", method = RequestMethod.GET)
        public @ResponseBody String findPet(@PathVariable String petId, @MatrixVariable String q) {
            return "petId="+petId+";"+"q="+q;
        }

路径：

http://localhost:8080/testwechat/mvctest/pets/42;q=1;q=2

结果：

![这里写图片描述][20160223114754107]

因为所有路径中都可以携带matrix 变量，所有需要明确指出matrix 变量所在的位置

// GET /owners/42;q=11/pets/21;q=22
    
    @RequestMapping(path = "/owners/{ownerId}/pets/{petId}", method = RequestMethod.GET)
    public void findPet(
            @MatrixVariable(name="q", pathVar="ownerId") int q1,
            @MatrixVariable(name="q", pathVar="petId") int q2) {
    
        // q1 == 11
        // q2 == 22
    }

matrix 变量是可选的，也可以是指默认值

/ GET /pets/42
    
    @RequestMapping(path = "/pets/{petId}", method = RequestMethod.GET)
    public void findPet(@MatrixVariable(required=false, defaultValue="1") int q) {
        // q == 1
    }

所有的matrix 变量都可以通过map获取

// GET /owners/42;q=11;r=12/pets/21;q=22;s=23
    
    @RequestMapping(path = "/owners/{ownerId}/pets/{petId}", method = RequestMethod.GET)
    public void findPet(
            @MatrixVariable Map<String, String> matrixVars,
            @MatrixVariable(pathVar="petId"") Map<String, String> petMatrixVars) { // matrixVars: ["q" : [11,22], "r" : 12, "s" : 23] // petMatrixVars: ["q" : 11, "s" : 23] }

![这里写图片描述][20160223120623068]

### **Request parameters** 使用@RequestParam ###

最常见的请求参数的一般在?后面携带，参数与参数之间用&连接格式如下

https://www.baidu.com/s?ie=UTF-8&wd=springmvc

这种参数的获取可以采用@RequestParam

//需要一个petId的参数
    @RequestMapping(path="useRequestParam",method = RequestMethod.GET)
        public @ResponseBody String requestParam(@RequestParam("petId") int petId) {
            return "petId:"+petId;
        }

![这里写图片描述][20160223150633047]

如果传递的参数是可选的需要将@RequestParam的required设为false

@RequestMapping(path="useRequestParam",method = RequestMethod.GET)
        public @ResponseBody String requestParam(@RequestParam(value="petId",required=false) int petId) {
            return "petId:"+petId;
        }

多个参数

@RequestMapping(path="useRequestParam1",method = RequestMethod.GET)
        public @ResponseBody String requestParam1(@RequestParam("petId") int petId,@RequestParam(value="petName",required=false) String petName) {
            return "petId:"+petId+"+petName:"+petName;
        }

![这里写图片描述][20160223152307959]

多个参数还可以用map来接收

@RequestMapping(path="useRequestParam3",method = RequestMethod.GET)
        public @ResponseBody String requestParam3(@RequestParam Map<String,String> map) {
            return map.toString();
        }

![这里写图片描述][20160223152403210]

## 2 表单传值 ##

表单传值分可为带文件上传的（需要将enctype设为multipart/form-data）和不带文件上传的（默认enctype为application/x-www-form-urlencoded）

### **不带文件的表单** ###

不带文件的表单和上面介绍的uri传值中的Request parameters用法一样，  
使用@RequestParam接收参数

@RequestMapping(path="postForm",method = RequestMethod.POST)
        public @ResponseBody String postForm(@RequestParam("username") String username,@RequestParam("password") String password) {
           return "username:"+username+"+password:"+password; 
        }

enctype为application/x-www-form-urlencoded

![这里写图片描述][20160223153542952]

enctype为multipart/form-data

![这里写图片描述][20160223153555542]

### **带文件上传的表单** ###

springmvc对文件上传的支持是通过multipartResolver来实现的，multipartResolver需要依赖commons-fileupload-x.x.jar和commons-io-x.x.jar

处理上传文件需要在springmvc的配置文件中加入如下bean

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
            <property name="maxUploadSize" value="10485760"></property>
            <property name="defaultEncoding" value="UTF-8"></property>
            <property name="resolveLazily" value="true"></property>
        </bean>

Controller  
springmvc会将参数中的变量自动绑定到对象中，如果对象的属性和参数的名称一致就可以绑定，在这个示例中，将参数绑定到一个User对象上，User对象如下

package com.wechat.controller.entiry;
    
    import javax.xml.bind.annotation.XmlElement;
    import javax.xml.bind.annotation.XmlRootElement;
    
    @XmlRootElement(name = "user")
    public class User { 
    
        private String username;
        private String password;
        private int age;
        @XmlElement
        public String getUsername() {
            return username;
        }
        public void setUsername(String username) {
            this.username = username;
        }
        @XmlElement
        public String getPassword() {
            return password;
        }
        public void setPassword(String password) {
            this.password = password;
        }
        @XmlElement
        public int getAge() {
            return age;
        }
        public void setAge(int age) {
            this.age = age;
        }
        @Override
        public String toString() {
            return "User [username=" + username + ", password=" + password + ", age=" + age + "]";
        }
    }

对象上的注解可以先不管，它是用来输出xml用的

Controller如下：

// 带文件的表单提交
        @RequestMapping(value = "postFile", method = RequestMethod.POST)
        @ResponseBody
        public String postFile(User user, @RequestParam MultipartFile[] myfiles, HttpServletRequest request)
                throws IOException {
    
            System.out.println(user.toString());
            for (MultipartFile myfile : myfiles) {
                if (myfile.isEmpty()) {
                    System.out.println("文件未上传");
                } else {
                    System.out.println("文件长度: " + myfile.getSize());
                    System.out.println("文件类型: " + myfile.getContentType());
                    System.out.println("表单名称: " + myfile.getName());
                    System.out.println("文件原名: " + myfile.getOriginalFilename());
                    System.out.println("========================================");
                    // 如果用的是Tomcat服务器，则文件会上传到\\%TOMCAT_HOME%\\webapps\\YourWebProject\\WEB-INF\\upload\\文件夹中
                    String realPath = request.getSession().getServletContext().getRealPath("/WEB-INF/upload");
                    // 这里不必处理IO流关闭的问题，因为FileUtils.copyInputStreamToFile()方法内部会自动把用到的IO流关掉
                    FileUtils.copyInputStreamToFile(myfile.getInputStream(),
                            new File(realPath, myfile.getOriginalFilename()));
                }
            }
            return "ok";
    
        }

![这里写图片描述][20160223161305760]

![这里写图片描述][20160223161413042]

可以同时上传多个文件

![myfiles][]

![myfiles][myfiles 1]

## 3 提交数据json或xml等 ##

通常在开发中会将数据以json或xml的形式提交到服务器端，这个时候需要采用@RequestBody来接收

可以提交任意字符串

@RequestMapping(value = "postJson", method = RequestMethod.POST)
        @ResponseBody
        public String postJson(@RequestBody String body) {
            System.out.println(body);
            return body;
        }

![这里写图片描述][20160223162810594]

需要提交json，只需要将提交的字符串按照json的格式提交即可，如果服务器的pojo能与之对应，则会自动绑定

![这里写图片描述][20160223163541886]

json需要classpath中有json相应的jar包，我的classpath中采用的是gson-2.4.jar

springmvc可以根据视图协商，为客户端提供不同的视图，可以通过后缀来告诉springmvc需要输出的数据格式为json还是xml

> By default Spring MVC performs “.*” suffix pattern matching so that a controller mapped to /person is also implicitly mapped to /person.*. This makes it easy to request different representations of a resource through the URL path (e.g. /person.pdf, /person.xml).

示例：

输出用户对象，根据客户端需求进行格式化，json需要引入的jar包采用gson就可以了，xml需要两个jar包，
    分别是xmlpull-1.1.3.1.jar和xstream-1.4.8.jar，同时需要在user对象上添加注解，注解已经添加在上面的程序中。

Controller

@RequestMapping(value = "postJsonBindUserNe", method = RequestMethod.POST)
                    @ResponseBody
                    public User postJsonBindUserNe(@RequestBody User user,@RequestHeader("Accept") String accept,@RequestHeader("Content-Type") String contentType) {
    
                        System.out.println("Accept:"+accept);
                        System.out.println("Content-Type:"+contentType);
                        return user;
    
                    }

返回json

![这里写图片描述][20160223165148415]

返回xml

![这里写图片描述][20160223165201822]

## 4 读取http头中的数据 ##

通常用户发往服务器的请求信息中除了数据本身，协议中也会携带非常有价值的内容，springmvc提供了强大的注解可以读取http头中的信息，使用的注解为@RequestHeader

示例仍然采用上面的请求用户示例，这次不用后缀名，将需要接收的类型包含在http头中

接受参数为json

![这里写图片描述][20160223170026888]

![这里写图片描述][20160223170036258]

提交的报文和返回的数据

![这里写图片描述][20160223170145150]

xml如下

![这里写图片描述][20160223170250123]

![这里写图片描述][20160223170258685]

报文和数据

![这里写图片描述][20160223170346309]

## 中文乱码 ##

上面的所有示例中均没有处理中文乱码，下面说一下乱码的处理方式

首先需要判断乱码出现的位置，以第一个示例为例

/owners/张学友

![这里写图片描述][20160223172658445]

断点，发现提交到Controller时并没有乱码，而是Controller输出的时候出现的乱码

原来

一切出自StringHttpMessageConverter

> By default, this converter supports all media types (\*/\*), and writes with a Content-  
> Type of text/plain. This can be overridden by setting the supportedMediaTypes property.

而它的编码方式为“ISO-8859-1”

![这里写图片描述][20160223173943100]

解决方法

<mvc:annotation-driven enable-matrix-variables="true"/>

改为如下

<mvc:annotation-driven enable-matrix-variables="true">
            
            <mvc:message-converters register-defaults="true">
                <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                    <property name="supportedMediaTypes" value="text/html;charset=UTF-8" />
                </bean>
            </mvc:message-converters>
        </mvc:annotation-driven>

或者在路径上添加如下参数

@RequestMapping(path="/owners/{ownerId}", method=RequestMethod.GET,produces = "text/html;charset=UTF-8")
        public @ResponseBody String findOwner(@PathVariable String ownerId) {
            return ownerId;
        }

参考

> [http://my.oschina.net/u/140421/blog/176625][http_my.oschina.net_u_140421_blog_176625]
> 
> [http://www.360doc.com/content/14/1024/23/18637323\_419613562.shtml][http_www.360doc.com_content_14_1024_23_18637323_419613562.shtml]

![这里写图片描述][20160223173229540]

springMVC传值就写到这里

参考文献

> [http://docs.spring.io/spring/docs/current/spring-framework-reference/htmlsingle/][http_docs.spring.io_spring_docs_current_spring-framework-reference_htmlsingle]  
> Spring官方文档

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[myfiles]: /images/20220731/dcc612c4ba654212afa40ea98d5bee2e.png
[myfiles 1]: /images/20220731/075ce365d7c84c05b876a53044fe788b.png
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[20160223173943100]: /images/20220731/9718cd571700437e830499336595b28c.png
[http_my.oschina.net_u_140421_blog_176625]: http://my.oschina.net/u/140421/blog/176625
[http_www.360doc.com_content_14_1024_23_18637323_419613562.shtml]: http://www.360doc.com/content/14/1024/23/18637323_419613562.shtml
[20160223173229540]: /images/20220731/974329dcaeba497d94c865ead4307e3a.png
[http_docs.spring.io_spring_docs_current_spring-framework-reference_htmlsingle]: http://docs.spring.io/spring/docs/current/spring-framework-reference/htmlsingle/