** 利用动态代理解决中英文乱码的问题**
**目的：无论是get方式还是post方式都不会出现中英文乱码的问题
思路：
-
新建一个web工程，然后新建一个HTML文件
-
新建一个Servlet
-
新建一个过滤器，在这个过滤器上对request上的getParameter（）进行增强
思路： 3.1 首先需要判断是get方式还是post方式。利用request.getMethod()方法 3.2如果是get方式，调用原先的request.getParameter(),返回的是一个字符串，对该字符串进行转码 3.3如果是post方式就设置request.setCharaterEncoding("utf-8")**
代码实现
html文件
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>gepost方式提交</h1>
<form action="/DynamicProxy/ServletDemo" method="post" >
User:<input type="" name="username"/><br/>
<input type="submit"/>
</form>
<h1>get方式提交</h1>
<form action="/DynamicProxy/ServletDemo" method="get" >
User:<input type="" name="username"/><br/>
<input type="submit"/>
</form></body>
</html>
新建一个Servlet
package com.it.test00;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class ServletDemo
*/
public class ServletDemo extends HttpServlet {
private static final long serialVersionUID = 1L;
public ServletDemo() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String um =request.getParameter("username");
System.out.println(request.hashCode()+" "+um);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String um =request.getParameter("username");
System.out.println(request.hashCode()+" "+um);
}
}
创建过滤器
package com.it.test00;
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;
import com.sun.xml.internal.bind.v2.runtime.reflect.opt.MethodAccessor_Short;
public class EncodingFilter implements Filter {
public EncodingFilter() {
}
public void destroy() {
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
//将request对象转换成HttpServletRequest
final HttpServletRequest req = (HttpServletRequest)request;
//让JDK在内存中生成代理对象：增强了req对象上的getParameter(name);
HttpServletRequest myReq = (HttpServletRequest)Proxy.newProxyInstance(EncodingFilter.class.getClassLoader(), req.getClass().getInterfaces(), new InvocationHandler() {
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
Object obj = null;
if(method.getName().equals("getParameter")) {
//获取本次请求的方式
String md = req.getMethod();
if("get".equalsIgnoreCase(md)) {
//get方式
String v =(String)method.invoke(req, args);
//转码
String vv = new String(v.getBytes("iso-8859-1"), "UTF-8");
return vv;
}else {
//post方式
req.setCharacterEncoding("UTF-8");
obj=method.invoke(req, args);
}
}else {
obj = method.invoke(req, args);
}
return obj;
}
});
//打印代理对象的哈希码，确保是同一个对象
System.out.println(myReq.hashCode());
//将代理对象放行
chain.doFilter(myReq, response);
}
public void init(FilterConfig fConfig) throws ServletException {
}
}
最终结果：
