Restful API SpringMVC多版本实现

项目要做多版本控制，于是百度了一下，发现有3种常用的实现方式。
####1.直接在url中添加版本信息，但是不符合restful要求

url : http://localhost:8080/multiversion/v1/print

####2.在content type中添加

url: http://localhost:8080/multiversion/print
Content-Type:application/json; version=2.0

####3.自定义http请求头

url: http://localhost:8080/multiversion/print
version:v2

  第二种没百度到，就选择了第三种，我们可以通过Ajax方法中的beforeSend添加自定义请求头。

$.ajax({
    type:"post",
    url:"http://localhost:8080/multiversion/print,
    dataType:"json",
    data:{},
    beforeSend:function(xhr){
        xhr.setRequestHeader("version", "v2");
    },
    success:function(data) {
        $("#sign").val(data);
    }
})

  这样在controller中的@RequestMapping的属性headers中写明版本即可。

@RequestMapping(headers = "version=v1",value = "print",method = RequestMethod.POST,produces = "application/json;charset=utf-8")
@ResponseBody
public ReturnResultUtil printV1(HttpServletRequest req) throws IOException {
    String version = req.getHeader("version");
    logger.info("this is "+ version);
    
    Map map = new HashMap();
    map.put("info","this is v1");
    return new ReturnResultUtil(1,"打印成功",version);
}
    
@RequestMapping(headers = "version=v2",value = "print",method = RequestMethod.POST,produces = "application/json;charset=utf-8")
@ResponseBody
public ReturnResultUtil printV2(HttpServletRequest req,String data) throws IOException {
    String version = req.getHeader("version");
    logger.info("this is "+ version);

    
    Map map = new HashMap();
    
    if(data == null || "".equals(data)){
         return new ReturnResultUtil(0,"data不能为空");
    }
    map.put("info","this is v2");
    map.put("params",data);
    return new ReturnResultUtil(1,"打印成功",map);
}

  SpringMVC注册request handler时把headers也放进去了(可以看启动日志)。

  虽然这样各自版本分的很清楚，也便于维护管理，但是每个方法都要注明版本号，如果两个版本只有很少的接口是不一样的，就会有大量重复的代码。
  所以也可以通过在方法内部获取请求头信息，然后做不同的处理，对于不同版本执行相同方法的直接不做处理。

   @RequestMapping(value = "print",method = RequestMethod.POST,produces = "application/json;charset=utf-8")
    @ResponseBody
    public ReturnResultUtil printLog(HttpServletRequest req,String data) throws IOException {
        
        Map map = new HashMap();
        String version = req.getHeader("version");
        logger.info("this is "+ version + " and params is " + data);
        //v1
        if("v1".equals(version)){
            map.put("info","this is v1");
            return new ReturnResultUtil(1,"打印成功",map);
        //v2
        }else if("v2".equals(version)){
            if(data == null || "".equals(data)){
                return new ReturnResultUtil(0,"data不能为空");
            }
            map.put("info","this is v2");
            map.put("params",data);
            return new ReturnResultUtil(1,"打印成功",map);
        }
        return new ReturnResultUtil(1,"打印成功",map);
    }