一、如何传递参数
使用 @RequestParam 可以传递查询参数。例如：http://localhost:8092/category/detail?id=1
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@RequestMapping
(
"/detail"
)
public
String detail(
@RequestParam
(
"id"
)
int
id,Model model){
Category category=
new
Category();
category.setCateId(id);
category.setCateName(
"测试分类"
+id);
model.addAttribute(
"cate"
,category);
return
"detail.html"
;
}
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使用 @PathVariable可以传递路径参数。例如：http://localhost:8092/category/edit/1
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@RequestMapping
(value =
"/edit/{id}"
,method = RequestMethod.GET)
public
String edit(
@PathVariable
(
"id"
)
int
id,Model model) {
//todo:get category from db
Category category=
new
Category();
category.setCateId(id);
category.setCateName(
"测试分类"
+id);
model.addAttribute(
"cate"
,category);
return
"edit.html"
;
}
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二、校验表单
1.首先定义实体类。
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public
class
Category{
public
Category(){}
@NotNull
@Min
(
1
)
private
int
cateId;
@NotNull
private
String cateName;
public
int
getCateId() {
return
cateId;
}
public
void
setCateId(
int
cateId) {
this
.cateId = cateId;
}
public
String getCateName() {
return
cateName;
}
public
void
setCateName(String cateName) {
this
.cateName = cateName;
}
}
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2.表单edit.html
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<form method=
"post"
th:object=
"${cate}"
th:action=
"@{/category/save}"
enctype=
"multipart/form-data"
>
<table>
<tr>
<td>id:</td>
<td><input type=
"text"
th:field=
"*{cateId}"
></td>
</tr>
<tr>
<td>name:</td>
<td><input type=
"text"
th:field=
"*{cateName}"
></td>
</tr>
<tr>
<td colspan=
"2"
>
<input type=
"submit"
value=
"提交"
>
</td>
</tr>
</table>
</form>
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3.通过给action方法的参数添加@Valid注解，这会告知Spring，需要确保这个对象满足校验限制
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@RequestMapping
(value =
"/save"
,method = RequestMethod.POST)
public
String save(
@Valid
Category category, Errors errors)
throws
IOException {...}
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错误可以通过Errors对象进行访问，现在这个对象已作为processRegistration()方法的参数。（很重要一点需要注意，Errors参数要紧跟在带有@Valid注解的参数后面，@Valid注解所标注的就是要检验的参数。
三、上传图片
1.设置web.xml配置
web.xml配置multipart-config
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<servlet>
<servlet-name>springmvc</servlet-name>
<servlet-
class
>org.springframework.web.servlet.DispatcherServlet</servlet-
class
>
<load-on-startup>
1
</load-on-startup>
<multipart-config>
<location></location>
<max-file-size>
2097152
</max-file-size>
<max-request-size>
4194304
</max-request-size>
</multipart-config>
</servlet>
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2.from表单
form要将enctype属性设置为multipart/form-data，这就告诉浏览器以multipart数据的形式提交表单
input标签要把type设置为file，这能够让用户选择要上传的图片文件。accept属性用来将文件类型限制为JPEG、PNG以及GIF图片。根据其name属性，图片数据将会发送到multipart请求中的profilePicture part之中
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<form method=
"post"
th:object=
"${cate}"
th:action=
"@{/category/save}"
enctype=
"multipart/form-data"
>
<table>
<tr>
<td>id:</td>
<td><input type=
"text"
th:field=
"*{cateId}"
></td>
</tr>
<tr>
<td>name:</td>
<td><input type=
"text"
th:field=
"*{cateName}"
></td>
</tr>
<tr>
<td>file:</td>
<td>
<input type=
"file"
accept=
"image/jpeg,image/png,image/jpg"
name=
"picture"
>
</td>
</tr>
<tr>
<td colspan=
"2"
>
<input type=
"submit"
value=
"提交"
>
</td>
</tr>
</table>
</form>
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3.controller:
@RequestPart ：图片对应的参数要添加该注解
spring提供了Multipart MultipartFile对象，它为处理multipart数据提供了内容更为丰富的对象
transferTo() ，它能够帮助我们将上传的文件写入到文件系统中
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@RequestMapping
(value =
"/save"
,method = RequestMethod.POST)
public
String save(
@RequestPart
(
"picture"
) MultipartFile picture,
@Valid
Category category, Errors errors)
throws
IOException {
//todo:save file to image server
String filepath=request.getRealPath(
"/"
)+
"upload/"
+picture.getOriginalFilename();
picture.transferTo(
new
File(filepath));
if
(errors.hasErrors()){
return
"edit.html"
;
}
//todo:save category to db
return
"redirect:/category/detail?id="
+category.getCateId();
}
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本文转自 陈敬（Cathy） 博客园博客，原文链接：http://www.cnblogs.com/janes/p/6933723.html，如需转载请自行联系原作者
