Filter解决POST,GET提交中文乱码问题

中文乱码是一个非常烦人的问题,没有学习Filter之前,每次都要进行转码

request.setCharacterEncoding("UTF-8");get还要进行转码.很是麻烦啊.后来学习到了Filter一下就可以只写一次,再也不用写了.妈妈再也不用担心我的乱码问题了.

另外说一下,tomcat8.0默认是UFT-8不用进行转码...

1.这个是用包装类,也可以用动态代理

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;

/**
 * 解决get和post请求 全部乱码
 */
public class GenericEncodingFilter implements Filter {

	@Override
	public void destroy() {
	}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		// 转型为与协议相关对象
		HttpServletRequest httpServletRequest = (HttpServletRequest) request;
		// 对request包装增强
		HttpServletRequest myrequest = new MyRequest(httpServletRequest);
		chain.doFilter(myrequest, response);
	}

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

}

// 自定义request对象
class MyRequest extends HttpServletRequestWrapper {

	private HttpServletRequest request;

	private boolean hasEncode;

	public MyRequest(HttpServletRequest request) {
		super(request);// super必须写
		this.request = request;
	}

	// 对需要增强方法 进行覆盖
	@Override
	public Map getParameterMap() {
		// 先获得请求方式
		String method = request.getMethod();
		if (method.equalsIgnoreCase("post")) {
			// post请求
			try {
				// 处理post乱码
				request.setCharacterEncoding("utf-8");
				return request.getParameterMap();
			} catch (UnsupportedEncodingException e) {
				e.printStackTrace();
			}
		} else if (method.equalsIgnoreCase("get")) {
			// get请求
			Map<String, String[]> parameterMap = request.getParameterMap();
			if (!hasEncode) { // 确保get手动编码逻辑只运行一次
				for (String parameterName : parameterMap.keySet()) {
					String[] values = parameterMap.get(parameterName);
					if (values != null) {
						for (int i = 0; i < values.length; i++) {
							try {
								// 处理get乱码
								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]; // 取回参数的第一个值
	}

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

}

2.动态代理的代码就少了一些

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);

	}
}