request:
//1.把乱码的数据打成iso-8859-1的字节数组
//2.把字节数组使用utf-8的编码方式重新组装成字符串
new String(字符串.getBytes("iso8859-1"), "utf-8");
response:二选一
response.setHeader("content-type","text/html;charset=utf-8")
response.setContentType("text/html;charset=utf-8")//比较常用的