SpringMVC中解决POST请求和GET请求中文乱码问题，以及直接访问返回前台的字符串中文乱码问题（json格式）

解决POST请求中文乱码问题

encoding是设置的request乱码问题，forceEncoding是设置的response乱码问题

<filter>
    <filter-name>CharacterEncodingFilter</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>
	<!--spring5之后就不需要配置forceEncoding了-->
    <init-param>
        <param-name>forceEncoding</param-name>
        <param-value>true</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>CharacterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

解决GET请求中文乱码问题解决GET请求中文乱码问题

狂老板推荐的大神过滤器

package com.zhang.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 init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
        //处理response的字符编码
        HttpServletResponse myResponse = (HttpServletResponse)response;
        //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);
        filterChain.doFilter(myRequest,myResponse);
    }

    @Override
    public void destroy() {

    }
}

class MyRequest extends HttpServletRequestWrapper {

    private HttpServletRequest request;
    private boolean hasEncode;

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

    @Override
    public Map getParameterMap() {
        String method = request.getMethod();
        if(method.equalsIgnoreCase("post")){
            try{
                request.setCharacterEncoding("utf-8");
                return request.getParameterMap();
            }catch (UnsupportedEncodingException e){
                e.printStackTrace();
            }
        }else if(method.equalsIgnoreCase("get")){
            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];
    }

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

怎么配置

<filter>
    <filter-name>encoding</filter-name>
    <filter-class>com.zhang.filter.GenericEncodingFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>encoding</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

JSON乱码问题（两种解决办法）

• 先看现象
  
  
• 办法一，@RequestMapping(value = "/j1",produces = "application/json;charset=utf-8")，这样的话，每个方法都得加，很麻烦；
  
• 办法二，在springmvc-servlet.xml中添加如下配置（需要导入jackson）

<!-- JSON乱码问题配置 -->
<mvc:annotation-driven>
    <mvc:message-converters register-defaults="true">
        <bean class="org.springframework.http.converter.StringHttpMessageConverter">
            <constructor-arg value="UTF-8"/>
        </bean>
        <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
            <property name="objectMapper">
                <bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
                    <property name="failOnEmptyBeans" value="false"/>
                </bean>
            </property>
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

再次访问，也可以解决；