rname = new String(rname.getBytes("iso-8859-1"),"utf-8");此代码报错

问题遇到的现象和发生背景

在学习黑马旅游网的代码时，加上一行代码就会报错，而去掉就正常

package cn.itcast.travel.web.servlet;

import cn.itcast.travel.domain.PageBean;
import cn.itcast.travel.domain.Route;
import cn.itcast.travel.service.impl.RouteService;
import cn.itcast.travel.service.impl.RouteServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/route/*")
public class RouteServlet extends BaseServlet {

    private RouteService routeService = new RouteServiceImpl();

    /**
     * 分页查询
     * @param request
     * @param response
     * @throws ServletException
     * @throws IOException
     */
    public void pageQuery(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.接受参数
        String currentPageStr = request.getParameter("currentPage");
        String pageSizeStr = request.getParameter("pageSize");
        String cidStr = request.getParameter("cid");

        //接受rname 线路名称
        String rname = request.getParameter("rname");
        rname = new String(rname.getBytes("iso-8859-1"),"utf-8");


        int cid = 0;//类别id
        //2.处理参数
        if(cidStr != null && cidStr.length() > 0 && !"null".equals(cidStr)){
            cid = Integer.parseInt(cidStr);
        }
        int currentPage = 0;//当前页码，如果不传递，则默认为第一页
        if(currentPageStr != null && currentPageStr.length() > 0){
            currentPage = Integer.parseInt(currentPageStr);
        }else{
            currentPage = 1;
        }

        int pageSize = 0;//每页显示条数，如果不传递，默认每页显示5条记录
        if(pageSizeStr != null && pageSizeStr.length() > 0){
            pageSize = Integer.parseInt(pageSizeStr);
        }else{
            pageSize = 5;
        }

        //3. 调用service查询PageBean对象
        PageBean<Route> pb = routeService.pageQuery(cid, currentPage, pageSize,rname);

        //4. 将pageBean对象序列化为json，返回
        writeValue(pb,response);

    }

}

问题相关代码，请勿粘贴截图

    rname = new String(rname.getBytes("iso-8859-1"),"utf-8");

只要加上这行，就会报错

运行结果及报错内容

java.lang.reflect.InvocationTargetException
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at cn.itcast.travel.web.servlet.BaseServlet.service(BaseServlet.java:36)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at cn.itcast.travel.web.filter.CharchaterFilter.doFilter(CharchaterFilter.java:32)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.base/java.lang.Thread.run(Thread.java:844)

应该不是这行，你把控制台错误的截图全部贴上来看看