806      阿裏雲  技術社區[雲棲]

JavaWeb項目的中文亂碼的原因以及Servlet中處理GET請求和POST請求編碼過濾器

一、亂碼原因

①傳輸方和接收方采用的編碼不一致。傳輸方對參數采用的是UTF-8編碼而接收方卻用GBK進行解析，當然是亂碼。

②Tomcat服務器默認采用的ISO8859-1編碼得到參數值。雖然①中采用了同樣的編碼方式，但經過tomcat一處理，也會出現亂碼(GET方式)

二、解決辦法

方法一 每次傳輸都手動設置編碼(GET方式傳輸數據)

傳輸方
String name = URLEncoder.encode("張三","UTF-8");
String path = "https://localhost:8008/xyWeb/xyServlet?name=" + name;

接收方
String name = new String(request.getParameter("name").getBytes("ISO8859-1"),"UTF-8");

若傳輸方默認采用UTF-8編碼就沒有必要每次寫，但接收方每次都寫太煩，可考慮過濾器。

方法二(過濾器)

/**
 * 編碼過濾器
 * 
 * @author xy
 * 
 */
public class EncodingFilter implements Filter
{
	private String encoding;

	public void init(FilterConfig fConfig) throws ServletException
	{
		encoding = fConfig.getInitParameter("encoding");
	}

	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws Exception
	{
		HttpServletRequest httprequest = (HttpServletRequest) request;
		if ("GET".equals(httprequest.getMethod()))
		{
			// 將httpRequest進行包裝
			EncodingHttpServletRequest wrapper = new EncodingHttpServletRequest(httprequest, encoding); 
			chain.doFilter(wrapper, response);
		}
		else
		{
			request.setCharacterEncoding(encoding);
			response.setContentType("text/html;charset=" + encoding);
			chain.doFilter(request, response);
		}
	}

	public void destroy()
	{

	}

}


/**
 * httpRequest進行包裝類
 * 
 * @author xy
 * 
 */
public class EncodingHttpServletRequest extends HttpServletRequestWrapper
{
	private HttpServletRequest request;
	private String encoding;

	public EncodingHttpServletRequest(HttpServletRequest request)
	{
		super(request);
		this.request = request;
	}

	public EncodingHttpServletRequest(HttpServletRequest request,String encoding)
	{
		super(request);
		this.request = request;
		this.encoding = encoding;
		
	}
	@Override
	public String getParameter(String name)
	{
		String value = request.getParameter(name);
		if (null != value)
		{
			try
			{
				// tomcat默認以ISO8859-1處理GET傳來的參數。把tomcat上的值用ISO8859-1獲取字節流，再轉換成UTF-8字符串
				value = new String(value.getBytes("ISO8859-1"), encoding);
			}
			catch (UnsupportedEncodingException e)
			{
				e.printStackTrace();
			}
		}
		return value;
	}

}

  <filter>
    <display-name>EncodingFilter</display-name>
    <filter-name>EncodingFilter</filter-name>
    <filter-class>cn.xy.filter.EncodingFilter</filter-class>
    <init-param>
      <description></description>
      <param-name>encoding</param-name>
      <param-value>UTF-8</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>EncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

最後更新：2017-04-03 20:19:30

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