HandlerMethodArgumentResolver

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概念

自定义HandlerMethodArgumentResolver可以理解为用一个对象封装需要查询的参数到后台查询相关值。

1.自定义注解

@Target({ElementType.PARAMETER, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface PropertyNaming {

}

---

2.实现方法

package cn.edu.xidian.see.ext;
//这里省略导入的包文件
...
//在编写之前应该实现此解决入参问题的接口
public class DataTableArgumentResolver implements HandlerMethodArgumentResolver {

    //1.首先需要实现的方法是：supportsParameter()方法
    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        // 仅作用于添加了注解DataTableArgument的参数
        return parameter.hasParameterAnnotation(DataTableArgument.class);
    }

    //2.然后重写resolveArgument方法
    @Override
    public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
            NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {

        DataTableRequest dtRequest = new DataTableRequest();

        if (webRequest.getParameter("draw") != null) {
            dtRequest.setDraw(Integer.valueOf(webRequest.getParameter("draw")));
        }
        if (webRequest.getParameter("start") != null) {
            dtRequest.setStart(Integer.valueOf(webRequest.getParameter("start")));
        }
        if (webRequest.getParameter("length") != null) {
            dtRequest.setLength(Integer.valueOf(webRequest.getParameter("length")));
        }

        Map<String, String[]> parameterMap = webRequest.getParameterMap();

        if (parameterMap.containsKey("search[value]")) {
            Search search = new Search();
            search.setValue(parameterMap.get("search[value]")[0]);
            search.setRegex(Boolean.valueOf(parameterMap.get("search[regex]")[0]));
            dtRequest.setSearch(search);
        }

        List<Order> orders = new ArrayList<>();
        int i = 0;
        String ockey = "order[" + i + "][column]", odkey;
        while (parameterMap.containsKey(ockey)) {

            odkey = "order[" + i + "][dir]";

            Order order = new Order();
            order.setColumn(Integer.valueOf(parameterMap.get(ockey)[0]));
            order.setDir(parameterMap.get(odkey)[0]);
            orders.add(order);

            ockey = "order[" + (++i) + "][column]";
        }
        dtRequest.setOrder(orders);

        List<Column> columns = new ArrayList<>();
        i = 0;
        String cdkey, cnkey, cskey, cokey, csvkey, csrkey;
        cdkey = "columns[" + i + "][data]";
        while (parameterMap.containsKey(cdkey)) {

            cnkey = "columns[" + i + "][name]";
            cskey = "columns[" + i + "][searchable]";
            cokey = "columns[" + i + "][orderable]";
            csvkey = "columns[" + i + "][search][value]";
            csrkey = "columns[" + i + "][search][regex]";

            Column column = new Column();
            column.setData(parameterMap.get(cdkey)[0]);
            column.setName(parameterMap.get(cnkey)[0]);
            column.setSearchable(Boolean.valueOf(parameterMap.get(cskey)[0]));
            column.setOrderable(Boolean.valueOf(parameterMap.get(cokey)[0]));
            Search search = new Search();
            search.setValue(parameterMap.get(csvkey)[0]);
            search.setRegex(Boolean.valueOf(parameterMap.get(csrkey)[0]));
            column.setSearch(search);
            columns.add(column);

            cdkey = "columns[" + (++i) + "][data]";
        }
        dtRequest.setColumns(columns);

        return dtRequest;
    }

}

---

3.使用方法

@RequestMapping(value = "/teacher/process", produces = {"application/json;charset=UTF-8"})
@ResponseBody
public String teacher_process(HttpSession session,
                                @DataTableArgument DataTableRequest dtRequest,
                                @RequestParam(value = "showColumns[]", required = false) String[] showColumns) throws Exception{
                                //controller程序实现  
                              }