java Tomcat的JspWriter编码不正确

Question

我有一个Tomcat 7的默认设置，所有与java相关的东西都配置为使用utf-8

这不起作用（utf-8字符被损坏）：

<%@ page language="java" pageEncoding="utf-8" contentType="text/html; charset=utf-8"%>
<%@ page import="java.net.*" %>
<%@ page import="java.io.*" %>
<%
    URL target = new URL("http://en.wikipedia.org/wiki/Main_Page");
    Reader input = new BufferedReader(new InputStreamReader(target.openStream()));
    StringWriter buffer = new StringWriter();
    char[] chrs = new char[1024 * 4];
    int n = 0;
    while (-1 != (n = input.read(chrs)))
    {
        buffer.write(chrs, 0, n);
    }
    StringReader reader = new StringReader(buffer.toString());
    n = 0;
    while (-1 != (n = reader.read(chrs)))
    {
        out.write(chrs, 0, n);
    } 
%>

确实如此，但会记录非法状态例外：

<%@ page language="java" pageEncoding="utf-8" contentType="text/html; charset=utf-8"%>
<%@ page import="java.net.*" %>
<%@ page import="java.io.*" %>
<%
    URL target = new URL("http://en.wikipedia.org/wiki/Main_Page");
    Reader input = new BufferedReader(new InputStreamReader(target.openStream()));
    StringWriter buffer = new StringWriter();
    char[] chrs = new char[1024 * 4];
    int n = 0;
    while (-1 != (n = input.read(chrs)))
    {
        buffer.write(chrs, 0, n);
    }
    StringReader reader = new StringReader(buffer.toString());
    OutputStreamWriter output = new OutputStreamWriter(response.getOutputStream());
    n = 0;
    while (-1 != (n = reader.read(chrs)))
    {
        output.write(chrs, 0, n);
    }
%>

我一直在寻找，但没有找到答案。这是Tomcat里的一只虫子，还是我遗漏了什么

Answer 1

当您构造^{}而不将字符集指定为第二个参数时，将使用平台默认编码，通常是ISO-8859-1。您需要指定与目标URL的响应头中指定的字符集相同的字符集，即UTF-8

input = new BufferedReader(new InputStreamReader(target.openStream(), "UTF-8"));

之所以产生IllegalStateException，是因为您是在JSP而不是Servlet中执行此操作的。JSP在内部使用^{}，但您在JSPscriptlet中调用^{}。这不能像javadoc中解释的那样同时完成