java - Spring MVC + 数据表 : bind array[] parameter

Question

简短的问题描述

我无法将 ...?name=John&sports[]=Volleyball&sports[]=Volleyball 之类的 url 参数转换为 Spring MVC 中的以下 Java 类。

class PersonFilter {       
    String name;
    List<String> sports; 
}

我需要在 sports[] 参数名称中使用括号。

长问题描述

我使用 DataTables 框架和 Spring MVC。 我需要向数据表 ajax 请求添加一些复杂的过滤器属性，如下所示:

$('#table').DataTable({
    serverSide: true,
    ajax: {
        url: "https://server/some/path",
        data: function (data) {
            data.name = "John",
            data.sports = ["Football", "Volleyball"]
        }
    }
});

创建了具有排序功能的 DataTables 请求(参数 order 和 columns)和自定义过滤器(参数 name 和 sports[])看起来像:

https://server/some/path?name=John&sports[]=Volleyball&sports[]=Football&columns[0][name]=name&order[0][column]=0&order[0][dir]=asc

我需要将 URL 参数绑定(bind)到包含 java.util.List 的 PersonFilter 类。

class PersonFilter {       
    String name;
    List<String> sports; 
}

Controller 看起来像:

@Controller
class PersonController {

    @RequestMapping(path = "/search")
    public List<Person> search(PersonFilter personFilter) {
       ...
    }
}

Spring 允许使用以下语法进行列表绑定(bind) ( http://docs.spring.io/spring/docs/current/spring-framework-reference/html/validation.html#beans-beans-conventions ):

1) sports=Volleyball&sports=Football -> OK
2) sports[0]=Volleyball&sports[1]=Football -> OK

但是 Spring 无法将名为 sports[] 的属性转换为 List。

sports[]=Volleyball&sports[]=Football -> FAILs (expects index in brackets)

java.lang.NumberFormatException: For input string: ""
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) ~[na:1.8.0_121]
    at java.lang.Integer.parseInt(Integer.java:592) ~[na:1.8.0_121]
    at java.lang.Integer.parseInt(Integer.java:615) ~[na:1.8.0_121]
    at org.springframework.beans.AbstractNestablePropertyAccessor.setPropertyValue(AbstractNestablePropertyAccessor.java:354) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.AbstractNestablePropertyAccessor.setPropertyValue(AbstractNestablePropertyAccessor.java:280) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:95) ~[spring-beans-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.validation.DataBinder.applyPropertyValues(DataBinder.java:859) ~[spring-context-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.validation.DataBinder.doBind(DataBinder.java:755) ~[spring-context-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.bind.WebDataBinder.doBind(WebDataBinder.java:192) ~[spring-web-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.bind.ServletRequestDataBinder.bind(ServletRequestDataBinder.java:106) ~[spring-web-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletModelAttributeMethodProcessor.bindRequestParameters(ServletModelAttributeMethodProcessor.java:150) ~[spring-webmvc-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.method.annotation.ModelAttributeMethodProcessor.resolveArgument(ModelAttributeMethodProcessor.java:114) ~[spring-web-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121) ~[spring-web-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:160) ~[spring-web-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:129) ~[spring-web-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) ~[spring-webmvc-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) ~[spring-webmvc-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) ~[spring-webmvc-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:622) ~[tomcat-embed-core-8.5.6.jar:8.5.6]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.5.RELEASE.jar:4.3.5.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) ~[tomcat-embed-core-8.5.6.jar:8.5.6]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) ~[tomcat-embed-core-8.5.6.jar:8.5.6]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) ~[tomcat-embed-core-8.5.6.jar:8.5.6]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.6.jar:8.5.6]

我尝试过的:

使用 JQuery ajax 设置 jQuery.ajaxSettings.traditional = true 。 但在这种情况下，用于排序(顺序、列)的 DataTables 参数会导致 [Object]，因此我无法解析排序参数。

https://server/some/path?name=John&sports=Volleyball&sports=Football&columns=[object Object]&order=[object Object]

谢谢您的建议!

Answer 1

最后我决定修改过滤器中请求的参数。

我创建了HttpServletRequestWrapper它从请求参数中删除括号 []。

public class JQueryArrayParameterRequestWrapper extends HttpServletRequestWrapper {
    public static final String BRACKETS_SUFFIX = "[]";

    private Map<String, String[]> _parameterMap;

    public JQueryArrayParameterRequestWrapper(HttpServletRequest request) {
        super(request);
    }

    @Override
    public Map<String, String[]> getParameterMap() {
        if (_parameterMap == null) {
            _parameterMap = modifyParameterMap(super.getParameterMap());
        }
        return _parameterMap;
    }

    @Override
    public Enumeration<String> getParameterNames() {
        return Collections.enumeration(getParameterMap().keySet());
    }

    @Override
    public String[] getParameterValues(String name) {
        return getParameterMap().get(name);
    }

    @Override
    public String getParameter(String name) {
        return getParameterValues(name) != null && getParameterValues(name).length > 0 ? getParameterValues(name)[0] : null;
    }

    private Map<String, String[]> modifyParameterMap(Map<String, String[]> oldParameterMap) {
        Map<String, String[]> newParameterMap = new HashMap<>(oldParameterMap.size());
        for (Map.Entry<String, String[]> entry : oldParameterMap.entrySet()) {
            String key = entry.getKey();
            if (key.endsWith(BRACKETS_SUFFIX)) {
                // remove brackets from parameter name
                String newKey = key.substring(0, key.length() - BRACKETS_SUFFIX.length());
                newParameterMap.put(newKey, entry.getValue());
            } else {
                // leave parameter unmodified
                newParameterMap.put(key, entry.getValue());
            }
        }
        return newParameterMap;
    }
}

然后我创建了过滤器:

public class JQueryArrayParameterFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        /* empty */
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        chain.doFilter(new JQueryArrayParameterRequestWrapper((HttpServletRequest) request), response);
    }

    @Override
    public void destroy() {
        /* empty */
    }
}

最后，我为 DataTables 请求注册了过滤器。

@Configuration
public class AppConfiguration { 
    @Bean
    public JQueryArrayParameterFilter jQueryArrayParameterFilter() {
        return new JQueryArrayParameterFilter();
    }

    @Bean
    public FilterRegistrationBean filterRegistrationBean(JQueryArrayParameterFilter filter) {
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(filter);
        filterRegistrationBean.addUrlPatterns( "/datatables/*");
        return filterRegistrationBean;
    }
}