Weblogic下Servlet异常java.lang.IllegalStateException

最新推荐文章于 2021-07-23 18:59:05 发布

原创最新推荐文章于 2021-07-23 18:59:05 发布 · 2.1k 阅读

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本文介绍了一种在WebLogic环境中解决Servlet出现java.lang.IllegalStateException异常的方法，通过自定义过滤器ContentTypePatchFilter允许在调用getWriter()之后更改ContentType。

Weblogic下Servlet异常java.lang.IllegalStateException

程序在tomcat环境下运行正常，但到weblogic下报以下错误：

Servlet failed with Exception java.lang.IllegalStateException: Attempt to change ContentType after calling getWriter() (cannot change charset from 'ISO-8859-1' to 'UTF-8')

经过网上到处搜索，问题主要是在weblogic本身

我们通过在web.xml中加一个过滤器来解决此问题

<filter>
<filter-name>ContentTypePatchFilter</filter-name>
<filter-class>com.fit.ContentTypePatchFilter</filter-class>
</filter>

<filter-mapping>
<filter-name>ContentTypePatchFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

ContentTypePatchFilter.java

package com.fit;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;

import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

public class ContentTypePatchFilter implements Filter{

    public void init(FilterConfig filterConfig) throws ServletException {
    }

    public void destroy(){
    }

public void doFilter(ServletRequest servletRequest,ServletResponse servletResponse,FilterChain filterChain) throws IOException, ServletException {
HttpServletResponse res = (HttpServletResponse) servletResponse;
NotUpsettingHttpServletResponse myResponse = new NotUpsettingHttpServletResponse(res);
filterChain.doFilter(servletRequest,myResponse);
}
}

NotUpsettingHttpServletResponse.java

package com.fit;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

public class NotUpsettingHttpServletResponse extends HttpServletResponseWrapper {
    private boolean gotWriter;
    private boolean gotOutputStream;
    public NotUpsettingHttpServletResponse(HttpServletResponse httpServletResponse) {
      super(httpServletResponse);
    }
    public void setContentType(String contentType) {
      if(isCommitted()||gotWriter||gotOutputStream){

      }else{
        super.setContentType(contentType);
      }
    }
    public PrintWriter getWriter() throws IOException {
      gotWriter = true;
      return super.getWriter();
    }
    public ServletOutputStream getOutputStream() throws IOException {
      gotOutputStream = true;
      return super.getOutputStream();
    }
}