anchor.diff:          String result = httpGet(urlString);
           result = result.replace("<", "&lt;");
           result = result.replace(">", "&gt;");
  -        out.println(result);
  +        out.println("<pre>" +result+ "</pre>");
       }
   %>
   <p>okhttp 调用方式: </p>
  
positive.code:             Response response = client.newCall(request).execute();
              result = response.body().string();
          } catch (Exception e) {
              result = "<pre>"+ Arrays.toString(e.getStackTrace()) +"<pre>";
          }
          return result;
      }
  
negative.code: <%@ page import="com.squareup.okhttp.OkHttpClient"%>
  <%@ page import="com.squareup.okhttp.Request"%>
  <%@ page import="com.squareup.okhttp.Response"%>
  <%@ page import="org.apache.commons.lang.StringUtils" %>
  <%@ page import="org.apache.commons.lang.exception.ExceptionUtils" %>
  <%@ page import="net.bytebuddy.implementation.bytecode.Throw" %>
  
  <%--
    Created by IntelliJ IDEA.
  