更改Request Parameters中的值

1. 定义ParameterRequestWrapper 继承HttpServletRequestWrapper

 

public class ParameterRequestWrapper extends HttpServletRequestWrapper {

	private Map<String,String[]> params;

	public ParameterRequestWrapper(HttpServletRequest request, Map<String,String[]> newParams) {
		super(request);
		this.params = newParams;
	}

	@Override
	public String getParameter(String name) {
		Object v = params.get(name);
		if (v == null) {
			return null;
		} else if (v instanceof String[]) {
			String[] strArr = (String[]) v;
			if (strArr.length > 0) {
				return strArr[0];
			} else {
				return null;
			}
		} else if (v instanceof String) {
			return (String) v;
		} else {
			return v.toString();
		}
	}

	@Override
	public Map getParameterMap() {
		return params;
	}

	@Override
	public Enumeration getParameterNames() {
		return new Vector(params.keySet()).elements();
	}

	@Override
	public String[] getParameterValues(String name) {
		Object v = params.get(name);
		if (v == null) {
			return null;
		} else if (v instanceof String[]) {
			return (String[]) v;
		} else if (v instanceof String) {
			return new String[] { (String) v };
		} else {
			return new String[] { v.toString() };
		}
	}

}

 

2. 在filter 中编写如下代码：

 

public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		HttpServletRequest httpRequest = (HttpServletRequest) request;
		Map<String, String[]> parametersMap = DataFormat
				.formatRequestParameters(httpRequest);
		ParameterRequestWrapper requestWrapper = new ParameterRequestWrapper(
				httpRequest, parametersMap);
		chain.doFilter(requestWrapper, response);
	}