中文亂碼是一個非常煩人的問題,沒有學習Filter之前,每次都要進行轉碼

request.setCharacterEncoding("UTF-8");get還要進行轉碼.很是麻煩啊.後來學習到了Filter一下就可以只寫一次,再也不用寫了.媽媽再也不用擔心我的亂碼問題了.

另外說一下,tomcat8.0預設是UFT-8不用進行轉碼...

1.這個是用包裝類,也可以用動態代理

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Map;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

/**
 * 解決get和post請求 全部亂碼
 */
public class GenericEncodingFilter implements Filter {

	@Override
	public void destroy() {
	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		// 轉型為與協議相關物件
		HttpServletRequest httpServletRequest = (HttpServletRequest) request;
		// 對request包裝增強
		HttpServletRequest myrequest = new MyRequest(httpServletRequest);
		chain.doFilter(myrequest, response);
	}

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
	}

}

// 自定義request物件
class MyRequest extends HttpServletRequestWrapper {

	private HttpServletRequest request;

	private boolean hasEncode;

	public MyRequest(HttpServletRequest request) {
		super(request);// super必須寫
		this.request = request;
	}

	// 對需要增強方法 進行覆蓋
	@Override
	public Map getParameterMap() {
		// 先獲得請求方式
		String method = request.getMethod();
		if (method.equalsIgnoreCase("post")) {
			// post請求
			try {
				// 處理post亂碼
				request.setCharacterEncoding("utf-8");
				return request.getParameterMap();
			} catch (UnsupportedEncodingException e) {
				e.printStackTrace();
			}
		} else if (method.equalsIgnoreCase("get")) {
			// get請求
			Map<String, String[]> parameterMap = request.getParameterMap();
			if (!hasEncode) { // 確保get手動編碼邏輯只執行一次
				for (String parameterName : parameterMap.keySet()) {
					String[] values = parameterMap.get(parameterName);
					if (values != null) {
						for (int i = 0; i < values.length; i++) {
							try {
								// 處理get亂碼
								values[i] = new String(values[i]
										.getBytes("ISO-8859-1"), "utf-8");
							} catch (UnsupportedEncodingException e) {
								e.printStackTrace();
							}
						}
					}
				}
				hasEncode = true;
			}
			return parameterMap;
		}

		return super.getParameterMap();
	}

	@Override
	public String getParameter(String name) {
		Map<String, String[]> parameterMap = getParameterMap();
		String[] values = parameterMap.get(name);
		if (values == null) {
			return null;
		}
		return values[0]; // 取回引數的第一個值
	}

	@Override
	public String[] getParameterValues(String name) {
		Map<String, String[]> parameterMap = getParameterMap();
		String[] values = parameterMap.get(name);
		return values;
	}

}
 

2.動態代理的程式碼就少了一些

import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

public class EncodingFilter implements Filter {
	public EncodingFilter() {
	}

	public void destroy() {
	}

	public void init(FilterConfig fConfig) throws ServletException {
	}

	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		
		final HttpServletRequest req = (HttpServletRequest) request;
		
		HttpServletRequest myReq = (HttpServletRequest) Proxy.newProxyInstance(
			EncodingFilter.class.getClassLoader(),req.getClass().getInterfaces(),
			new InvocationHandler() {	
				
				public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
					Object obj = null;
					
					if(method.getName().equalsIgnoreCase("getParameter")) {
						String reqMethod = req.getMethod();
						if("get".equalsIgnoreCase(reqMethod)) {
							
							String str = (String) method.invoke(req, args);
							System.out.println("GET "+str);
							String strUTF = new String(str.getBytes("ISO-8859-1"),"UTF-8");
							System.out.println("GET "+strUTF);
							return strUTF;						
							
						}else {
							req.setCharacterEncoding("UTF-8");
							obj = method.invoke(obj, args);
						}	
						
					}else {
						obj = method.invoke(req , args);
					}
		
					return obj;
				}
			});
		
		
		chain.doFilter(myReq, response);

	}
}