乱码问题

乱码分为请求乱码,响应乱码

请求乱码分为 get请求和post请求

如果是post请求,则简单一点,request.setCharacterEncoding("utf-8");

如果是get 请求  则要麻烦一点,对于获取的值进行编解码  String str2=new String(str.getBytes("iso8859-1"),"utf-8");

如果想解决全站乱码就要用到过滤器了(因为我们从request中获取到值的时候已经是乱码了,所以要想解决乱码就要解决request几个方法的乱码问题,大致是这三个方法,request.getParameters(),getParameterValues(),getParameterMap()).

在这三个方法中解决乱码问题,首先我们想到的是过滤器,当请求进来的时候我们对请求进行过滤拦截,然后对request进行包装,并重写这三个方法,在方法中根据请求类型进行乱码处理

具体看下面代码:

package filter;

import java.io.IOException;

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.HttpServletResponse;

public class MyFilter implements Filter {

@Override
public void destroy() {
// TODO Auto-generated method stub

}

@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest myRequest=(HttpServletRequest)request;     //强转
HttpServletResponse myResponse=(HttpServletResponse)response;//

myRequest.setCharacterEncoding("utf-8");                                     //设置请求编码,只对post有效
myResponse.setCharacterEncoding("utf-8");                                    //设置服务器响应编码格式
myResponse.setContentType("text/html;charset=utf-8");                 //设置响应页面编码格式和编码格式

MyRequest mr=new MyRequest(myRequest);                                  //对request进行包装并继承HttpServletRequestWrapper并重写三个方法;
chain.doFilter(mr, myResponse);                                                     //放行

}

@Override
public void init(FilterConfig filterConfig) throws ServletException {
// TODO Auto-generated method stub

}

}

//重写三个方法,进行重新编码

package filter;

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

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;

public class MyRequest extends HttpServletRequestWrapper {

private HttpServletRequest request;

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


@Override
public String getParameter(String name) {
try {
String type =this.request.getMethod();
String myName = this.request.getParameter(name);
if ("get".equalsIgnoreCase(type)) {

return new String(myName.getBytes("iso8859-1"),"utf-8");
}
return myName;
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
throw new RuntimeException();
}

}

@Override
public Map getParameterMap() {
try {
String type = this.request.getMethod();
Map<String,String[]> map = this.request.getParameterMap();
if(map!=null&&"get".equalsIgnoreCase(type)){
Set<String> keySet = map.keySet();
for (String key : keySet) {
String[] strings = map.get(key);
if (strings!=null&&strings.length!=0) {
for (int i = 0; i < strings.length; i++) {
strings[i]=new String(strings[i].getBytes("iso8859-1"),"utf-8");
}
}
}

}
return map;
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
throw new RuntimeException("getParameterMap出错");
}
}

@Override
public String[] getParameterValues(String name) {

try {
String type = this.request.getMethod();
String[] values = this.request.getParameterValues(name);
if("get".equalsIgnoreCase(type)){
if (values!=null&&values.length!=0) {
for (int i = 0; i < values.length; i++) {
values[i]=new String(values[i].getBytes("iso8859-1"),"utf-8");
}
}
}
return values;
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
throw new RuntimeException("getParameterValues出错");
}
}

}

最后,不要忘记在web.xml中配置过滤器

<filter>
<filter-name>myFilter</filter-name>
<filter-class>filter.MyFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>myFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>