Spring RestController 请求参数详解

在阅读之前，最好先了解http请求的get,post,以及各种head头类型，请求参数类型。

无参数，设置RestController请求路径
查询字符串参数，可选和必选参数
json参数，RestController用实体类型接受
路径参数
body参数
文件流参数

1 无参数，设置RestController请求路径

下面是一个例子，例子无请求参数，通过@RequestMapping设置了请求的路由路径和请求方法。路由路由由类的mapping和方法的mapping组成，在后面的例子中，我就不再写出RestApiRequestDemoController类的mapping了。记住，url里面有个demo在前面。

@RestController
@RequestMapping("/demo")
public class RestApiRequestDemoController {
<span class="c1">///方法说明: 普通查询</span>
<span class="c1">///示例请求：http://localhost:8091/demo/list</span>
<span class="nd">@RequestMapping</span><span class="o">(</span><span class="n">value</span><span class="o">=</span><span class="s">"/searchList"</span><span class="o">,</span><span class="n">method</span> <span class="o">=</span> <span class="n">RequestMethod</span><span class="o">.</span><span class="na">POST</span><span class="o">)</span>
<span class="nd">@ResponseBody</span>
<span class="kd">public</span> <span class="n">List</span><span class="o">&lt;</span><span class="n">UserModel</span><span class="o">&gt;</span> <span class="nf">searchList</span><span class="o">()</span> <span class="o">{</span>
    <span class="n">List</span> <span class="n">list</span> <span class="o">=</span> <span class="k">new</span> <span class="n">list</span><span class="o">();</span>
    <span class="k">return</span> <span class="n">list</span><span class="o">;</span>
<span class="o">}</span>

}

2 查询字符串参数，可选和必选参数2. 查询字符串参数，可选和必选参数

下面是使用查询字符串的例子，required可以设置请求的字符串是否必填

///方法说明：url参数的使用-查询字符串 ,且name必填
///示例请求：http://localhost:8091/demo/searchListByName?name=liuyanwei
@RequestMapping(value="/listByName",method = RequestMethod.POST)
@ResponseBody
public List<TbUserModel> searchList(@RequestParam(value="name",required = true) String name) {
<span class="n">Session</span> <span class="n">context</span> <span class="o">=</span> <span class="n">DatabaseHelper</span><span class="o">.</span><span class="na">context</span><span class="o">();</span>
<span class="n">String</span> <span class="n">sql</span> <span class="o">=</span> <span class="s">"select * from tb_user where name ='"</span><span class="o">+</span> <span class="n">name</span><span class="o">+</span><span class="s">"'"</span> <span class="o">;</span>
<span class="n">List</span> <span class="n">list</span> <span class="o">=</span> <span class="n">context</span><span class="o">.</span><span class="na">createSQLQuery</span><span class="o">(</span><span class="n">sql</span><span class="o">)</span>
        <span class="o">.</span><span class="na">setResultTransformer</span><span class="o">(</span><span class="n">Transformers</span><span class="o">.</span><span class="na">aliasToBean</span><span class="o">(</span><span class="n">TbUserModel</span><span class="o">.</span><span class="na">class</span><span class="o">))</span>
        <span class="o">.</span><span class="na">list</span><span class="o">();</span>
<span class="k">return</span> <span class="n">list</span><span class="o">;</span>

}

3 json参数，RestController用实体类型接受

注意，需要设置application/json 否则数据库会返回。hibernate操作数据库代码暂时可以不用去管他。

/*
* 方法说明：添加数据
* 1:使用json数据提交，直接使用实体对象接收
* 2:hibernate 添加数据
* 请求参数： {"id":1,"userId":1,"pwd":"123","name":"123","pwd":"123","headPortait":"123","isEnable":"123","createDate":"2015-05-12","lastLogin":"2015-05-12"}
* 请求头：Content-Type : application/json
* 请求ur：http://localhost:8091/demo/addUser
* */
@RequestMapping(value="/addUser",method = RequestMethod.POST)
@ResponseBody
public TbUserModel addUser(@RequestBody TbUserModel user) {
<span class="n">Session</span> <span class="n">context</span> <span class="o">=</span> <span class="n">DatabaseHelper</span><span class="o">.</span><span class="na">context</span><span class="o">();</span>
<span class="n">Transaction</span> <span class="n">tran</span> <span class="o">=</span> <span class="n">context</span><span class="o">.</span><span class="na">beginTransaction</span><span class="o">();</span>
<span class="n">context</span><span class="o">.</span><span class="na">save</span><span class="o">(</span><span class="n">user</span><span class="o">);</span>
<span class="n">tran</span><span class="o">.</span><span class="na">commit</span><span class="o">();</span>
<span class="n">user</span><span class="o">.</span><span class="na">setId</span><span class="o">(</span><span class="n">user</span><span class="o">.</span><span class="na">getId</span><span class="o">());</span>
<span class="n">context</span><span class="o">.</span><span class="na">close</span><span class="o">();</span>
<span class="k">return</span> <span class="n">user</span><span class="o">;</span>

}

4 路径参数

路径参数不能设置是否必填，全部都是必须填，不能省略的

///方法说明：url参数的使用
///示例请求：http://localhost:8091/demo/searchListById/2
@RequestMapping(value="/searchListById/{id}",method = RequestMethod.POST)
@ResponseBody
public List<TbUserModel> searchList(@PathVariable("id") int id) {
 <span class="n">Session</span> <span class="n">context</span> <span class="o">=</span> <span class="n">DatabaseHelper</span><span class="o">.</span><span class="na">context</span><span class="o">();</span>
<span class="c1">//        String sql = "select * from tb_user where id ="+ id ;</span>
 <span class="n">String</span> <span class="n">sql</span> <span class="o">=</span> <span class="s">"select * from tb_user where tb_user.id = :id"</span><span class="o">;</span>
 <span class="n">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="n">sql</span><span class="o">);</span>
 <span class="n">List</span> <span class="n">list</span> <span class="o">=</span> <span class="n">context</span><span class="o">.</span><span class="na">createSQLQuery</span><span class="o">(</span><span class="n">sql</span><span class="o">).</span><span class="na">setInteger</span><span class="o">(</span><span class="s">"id"</span><span class="o">,</span> <span class="n">id</span><span class="o">)</span>
         <span class="o">.</span><span class="na">setResultTransformer</span><span class="o">(</span><span class="n">Transformers</span><span class="o">.</span><span class="na">aliasToBean</span><span class="o">(</span><span class="n">TbUserModel</span><span class="o">.</span><span class="na">class</span><span class="o">))</span>
         <span class="o">.</span><span class="na">list</span><span class="o">();</span>
 <span class="k">return</span> <span class="n">list</span><span class="o">;</span>

}

高级用法：路径参数可以自由设置自己的规则，比如，你有个请求需要两个参数，月和日，你可以写成{month}-{day}

///方法说明：url参数的使用
///示例请求：http://localhost:8091/demo/searchListByDate/2-10
@RequestMapping(value="/searchListByDate/{month}-{day}",method = RequestMethod.POST)
@ResponseBody
public List<TbUserModel> searchList(@PathVariable("month") int month,
                                    @PathVariable("day") int day) {
}

5. 表单参数参数

注意，

这种方式传参数不能设置参数选填
注意，参数写在boby中，相当于表单参数，必须设置请求头为：application/x-www-form-urlencoded
若参数不正确，是无法进入控制器的。

    /*
    * 方法说明：使用表单方式提交数据
    * 请求参数:isEnable=1&name=cool
    * 配置
    * 请求头：Content-Type : application/x-www-form-urlencoded
    * 请求url：http://localhost:8091/demo/findUsersByName
    * */
    @RequestMapping(value="/findUsersByName",method = RequestMethod.POST)
    @ResponseBody
    public void findUsersByName(boolean isEnable , String name)
    {
        System.out.println(isEnable);
        System.out.println(name);
    }

6. 文件流参数

单个文件通过这种方式 @RequestParam(“file”) MultipartFile file获得，这里是简单的写法,相当于 MultipartFile file = ((MultipartHttpServletRequest) request).getFile(“file”); 多个文件使用@RequestParam(“files”) MultipartFile[] files)
表单中文件的name属性必须设置file（注意，不是文件名），例如，html中 <input type="files" name="file" > </li>
这个是简单获取文件的方式，若不知道表单中文件的name属性,可以通过request获取文件

例子：

@RequestMapping("upload")
public Resp upload(HttpServletRequest request,
                   HttpServletResponse response, @RequestParam("file") MultipartFile file){
<span class="k">try</span> <span class="o">{</span>
    <span class="c1">//MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;</span>
    <span class="n">String</span> <span class="n">filePath</span> <span class="o">=</span> <span class="n">FilesService</span><span class="o">.</span><span class="na">uploadFile</span><span class="o">(</span><span class="n">file</span><span class="o">,</span> <span class="n">request</span><span class="o">);</span>
    <span class="k">return</span> <span class="n">Resp</span><span class="o">.</span><span class="na">succeedResp</span><span class="o">(</span><span class="n">filePath</span><span class="o">);</span>
<span class="o">}</span>
<span class="k">catch</span> <span class="o">(</span><span class="n">Exception</span> <span class="n">e</span><span class="o">){</span>
    <span class="n">e</span><span class="o">.</span><span class="na">printStackTrace</span><span class="o">();</span>
<span class="o">}</span>

<span class="k">return</span> <span class="n">Resp</span><span class="o">.</span><span class="na">failureResp</span><span class="o">(</span><span class="s">"图片上传失败"</span><span class="o">);</span>

}
@RequestMapping("batchUpload")

public Resp batchUpload(HttpServletRequest request,

HttpServletResponse response,

@RequestParam("files") MultipartFile[] files) throws IOException {

List<String> list = new ArrayList<String>();

try {

for (MultipartFile file :files) {

String filePath = FilesService.uploadFile(file, request);

list.add(filePath);

System.out.println("filePath:" + filePath);

}

return Resp.succeedResp(list);

}

catch (Exception e){

e.printStackTrace();

}

return  Resp.failureResp("文件上传失败");

}

总结

想要把Rest风格的api用好，合理利用参数是必须的。不同功能的api使用不同类型的参数接收方式。每个人有不同的习惯，我的习惯是：

一般获取内容，不涉及加密的用get方法，设计加密的用post
提交内容，例如添加，删除，修改，使用post、delete、put方法
通过主键获取内容的，我习惯用url参数，例如:/news/details/1,参数不是很多，组合起来有意义的也会用url路径组合，例如前面的日期:/demo/searchListByDate/2-10
有时候接收参数组合起来用比较好，有的内容通过url参数，有的部分用表单内容。
所有的设计接收参数的原则就是，然你的api的url能读通，看起来合理。

好了，就到这了，后面有时间我会再写一些hibernate 数据操作的例子和hibernate获取实体参数验证的内容，有的问题我也还没完全搞清楚，后面在研究看看。

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