springmvc 11 json与HttpMessageCon

返回json格式数据

1. 新加入jar包
去官网下载

http://wiki.fasterxml.com/JacksonDownload

2. 编写目标方法，使其返回json对应的对象或集合
3. 在方法上加入@ResponseBody

    @ResponseBody
    @RequestMapping("/testJson")
    public Collection testJson(){
        return deptDao.getAll();
    }

HttpMessageConverter

HttpMessageConverter的原理

https://my.oschina.net/lichhao/blog/172562

@ResponseBody,@RequestBody的使用

Paste_Image.png

    <form action="testHttpMessageConverter" method="post" enctype="multipart/form-data">
        File:<input type="file" name="file"/><br>
        Desc:<input type="text" name="desc"/><br>
        <input type="submit" value="Submit"/>
    </form>

    @ResponseBody
    @RequestMapping("/testHttpMessageConverter")
    public String testHttpMessageConverter(@RequestBody String body){
        /* 参数类型为String
         * 那么springmvc会使用StringHttpMessageConverter
         * 把传入的参数的信息转换为String类型*/

        System.out.println("参数为："+body);
        return "hello"+new Date();
        /* 返回类型为String
         * 那么springmvc会使用StringHttpMessageConverter
         * 把返回的信息转换为String类型*/
    }

后台打印:

参数为：------WebKitFormBoundaryyBSL9T1T2Yqc5tDY
Content-Disposition: form-data; name="file"; filename="dd.txt"
Content-Type: text/plain

I love china
------WebKitFormBoundaryyBSL9T1T2Yqc5tDY
Content-Disposition: form-data; name="desc"

abcd
------WebKitFormBoundaryyBSL9T1T2Yqc5tDY--

response.gif

@ResponseEntity的使用(文件下载)

<a href="testResponseEntity">testResponseEntity</a>

    @RequestMapping("/testResponseEntity")
    public ResponseEntity<byte[]> testResponseEntity(HttpSession session){
        byte[] body = null;
        ServletContext servletContext = session.getServletContext();
        InputStream in = servletContext.getResourceAsStream("WEB-INF/files/dd.txt");
        
        try {
            body = new byte[in.available()];
            in.read(body);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        HttpHeaders httpHeader = new HttpHeaders();
        httpHeader.add("Content-Disposition", "attachment;filename=dd.txt");
        
        HttpStatus httpStatus = HttpStatus.OK;
        
        ResponseEntity<byte[]> responseEntity = new ResponseEntity<byte[]>(body,httpHeader,httpStatus);
        return responseEntity;
    }
}