乱码问题
我们经常在web的开发中遇到许多的乱码问题,比如请求参数乱码和响应乱码等,在这里列举了在开发中乱码解决的三种方式:
方式一、自定义Filter过滤器
Filter过滤器的作用:拦截请求,对符合条件的请求放行,对不符合条件的请求进行拦截,并可以对请求进行处理。
**第一步:**这种方式首先要将自定义类实现javax.servlet.Filter接口,重写三个方法,并在doFilter()方法中设置服务器编码servletRequest.setCharacterEncoding("UTF-8");
和浏览器编码servletResponse.setContentType("text/html;charset=UTF-8");
最后不要忘记了放行请求,filterChain.doFilter(servletRequest, servletResponse);
package com.monster.Filter;
import javax.servlet.*;
import java.io.IOException;
/**
* @author Monster
* @version v1.0
* @time 02-28-2021 15:11:24
* @description:
*/
public class MyFilter implements Filter {
public void init(FilterConfig filterConfig) throws ServletException {
}
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
servletRequest.setCharacterEncoding("UTF-8");
servletResponse.setContentType("text/html;charset=UTF-8");
filterChain.doFilter(servletRequest, servletResponse);
}
public void destroy() {
}
}
**第二步:**在web.xml中配置
/ 和 /的区别:
/ 只会对我们自己编写的请求进行拦截,并不会拦截到 .jsp结尾的文件的请求。
/ 拦截所有的请求。
<filter>
<filter-name>MyFilter</filter-name>
<filter-class>com.monster.Filter.MyFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>MyFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
方式二:使用spring为我们提供的过滤器
直接在web.xml文件中配置一下内容即可:
<filter>
<filter-name>encoding</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encoding</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
但有时这种处理方式对get请求不是太好,我们可以修改Tomcat中的配置文件
<Connector URIEncoding="utf-8" port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
方式三:通用的过滤器
package com.monster.filter;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Map;
/**
* 解决get和post请求 全部乱码的过滤器
*/
public class GenericEncodingFilter implements Filter {
@Override
public void destroy() {
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
//处理response的字符编码
HttpServletResponse myResponse=(HttpServletResponse) response;
myResponse.setContentType("text/html;charset=UTF-8");
// 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,HttpServletRequest的包装类
class MyRequest extends HttpServletRequestWrapper {
private HttpServletRequest request;
//是否编码的标记
private boolean hasEncode;
//定义一个可以传入HttpServletRequest对象的构造函数,以便对其进行装饰
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();
}
//取一个值
@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
}
//取所有值
@Override
public String[] getParameterValues(String name) {
Map<String, String[]> parameterMap = getParameterMap();
String[] values = parameterMap.get(name);
return values;
}
}
这个是网上某位大神写的,这里只是借鉴,基本上spring自带的处理乱码的方式几乎就可以解决所有的乱码问题,而我们平时在写代码的时候能设置编码的地方尽量写成UTF-8。