jsp必须为gbk编码时候，java代码中getParameter获得中文出现乱码解决方案

本人对java,jsp等相关网页只是很不熟悉，今日为了修改别人留下来的java后台html中嵌套jsp做界面的项目中的一些内容受尽了折磨。在text或者textarea中传入中文的时候，getParameter方法总是得到一堆？，无人可问，只好在网上盲目的找。网上有好多更改jsp编码的方法，也有很多在java中对编码进行各种转换的，试了又试，没什么用。或许可以成功吧，但是我的情况是，当前jsp引用了别的jsp，然而别的jsp从gbk变成utf-8之后就报了html-500的错误，为了不引起更多的未知错误，我放弃了修改界面编码的方向的尝试。而后在CSDN的一帖子中高分的18楼的解决方法帮助了我，为了避免忘记，本人将该帖子引用至此，地址http://bbs.csdn.net/topics/390360298。我们再来看一看这个神奇的类：

public class HttpRequestReader {

    Hashtable pairs = new Hashtable();

    /**
     * RawParameterReader constructor comment.
     */
    public HttpRequestReader(HttpServletRequest request, String encoding)
            throws IOException {
        super();
        parse(request.getQueryString(), encoding);
        parse(request.getReader().readLine(), encoding);
    }

    public static String decode(String s, String encoding) throws Exception {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            switch (c) {
            case '+':
                sb.append(' ');
                break;
            case '%':
                try {
                    sb.append((char) Integer.parseInt(
                            s.substring(i + 1, i + 3), 16));
                } catch (NumberFormatException e) {
                    throw new IllegalArgumentException();
                }
                i += 2;
                break;
            default:
                sb.append(c);
                break;
            }
        }
        // Undo conversion to external encoding
        String result = sb.toString();
        byte[] inputBytes = result.getBytes("8859_1");
        return new String(inputBytes, encoding);
    }

    /**
     * Insert the method's description here. Creation date: (2001-2-4 17:30:59)
     * 
     * @return java.lang.String
     * @param name
     *            java.lang.String
     */
    public String getParameter(String name) {
        if (pairs == null || !pairs.containsKey(name))
            return null;
        return (String) (((ArrayList) pairs.get(name)).get(0));
    }

    /**
     * Insert the method's description here. Creation date: (2001-2-4 17:28:17)
     * 
     * @return java.util.Enumeration
     */
    public Enumeration getParameterNames() {
        if (pairs == null)
            return null;
        return pairs.keys();
    }

    /**
     * Insert the method's description here. Creation date: (2001-2-4 17:33:40)
     * 
     * @return java.lang.String[]
     * @param name
     *            java.lang.String
     */
    public String[] getParameterValues(String name) {
        if (pairs == null || !pairs.containsKey(name))
            return null;
        ArrayList al = (ArrayList) pairs.get(name);
        String[] values = new String[al.size()];
        for (int i = 0; i < values.length; i++)
            values[i] = (String) al.get(i);
        return values;
    }

    /**
     * Insert the method's description here. Creation date: (2001-2-4 20:34:37)
     * 
     * @param urlenc
     *            java.lang.String
     */
    private void parse(String urlenc, String encoding)
            throws java.io.IOException {
        if (urlenc == null)
            return;
        StringTokenizer tok = new StringTokenizer(urlenc, "&");
        try {
            while (tok.hasMoreTokens()) {
                String aPair = tok.nextToken();
                int pos = aPair.indexOf("=");
                String name = null;
                String value = null;
                if (pos != -1) {
                    name = decode(aPair.substring(0, pos), encoding);
                    value = decode(aPair.substring(pos + 1), encoding);
                } else {
                    name = aPair;
                    value = "";
                }
                if (pairs.containsKey(name)) {
                    ArrayList values = (ArrayList) pairs.get(name);
                    values.add(value);
                } else {
                    ArrayList values = new ArrayList();
                    values.add(value);
                    pairs.put(name, values);
                }
            }
        } catch (Exception e) {
            throw new java.io.IOException(e.getMessage());
        }
    }
}

在我引入到我的java工程之后又添加了已下的包：

import java.io.IOException;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.StringTokenizer;

import javax.servlet.http.HttpServletRequest;

以便可以使用。

在需要的地方做已下应用：

public void save(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        try {
            HttpRequestReader paramReader = new HttpRequestReader(req, "gbk");
            String strAlertMsg = paramReader.getParameter("device.AlertMsg");
        } catch (Exception e) {
            this.findForward("/device-details.jsp", true, req, resp);
            return;
        }
        this.findForward("/device-details.jsp", true, req, resp);
        return;
}

然后就OK啦！