Java 重写ServletResponse中的内容

Myth丶恋晨 2022-06-04 05:39 87阅读 0赞

Java 重写ServletResponse中的内容，Java 修改response中的内容

1. 继承HttpServletResponseWrapper 重新覆盖Response对象

package com.hbzx.interceptor;
    
    import java.io.ByteArrayOutputStream;
    import java.io.IOException;
    import java.io.OutputStreamWriter;
    import java.io.PrintWriter;
    import java.io.UnsupportedEncodingException;
    
    import javax.servlet.ServletOutputStream;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpServletResponseWrapper;
    
    public class UrlResponseWrapper extends HttpServletResponseWrapper {
    	private ByteArrayOutputStream buffer = null;
    	private ServletOutputStream out = null;
    	private PrintWriter writer = null;
    
    	public UrlResponseWrapper(HttpServletResponse resp) throws IOException {
    		super(resp);
    		buffer = new ByteArrayOutputStream();// 真正存储数据的流
    		out = new WapperedOutputStream(buffer);
    		writer = new PrintWriter(new OutputStreamWriter(buffer));
    	}
    
    	@Override
    	public ServletOutputStream getOutputStream() throws IOException {
    		return out;
    	}
    
    	@Override
    	public PrintWriter getWriter() throws UnsupportedEncodingException {
    		return writer;
    	}
    
    	@Override
    	public void flushBuffer() throws IOException {
    		if (out != null) {
    			out.flush();
    		}
    		if (writer != null) {
    			writer.flush();
    		}
    	}
    	
    	@Override
    	public void reset() {
    		buffer.reset();
    	}
    
    	public byte[] getResponseData() throws IOException {
    		flushBuffer();
    		return buffer.toByteArray();
    	}
    	
    	public String getContent() throws IOException{
    		flushBuffer();
    		return buffer.toString();
    	}
    
    	private class WapperedOutputStream extends ServletOutputStream {
    		private ByteArrayOutputStream bos = null;
    
    		public WapperedOutputStream(ByteArrayOutputStream stream) throws IOException {
    			bos = stream;
    		}
    
    		@Override
    		public void write(int b) throws IOException {
    			bos.write(b);
    		}
    
    		@Override
    		public void write(byte[] b) throws IOException {
    			bos.write(b, 0, b.length);
    		}
    
    		@Override
    		public void write(byte[] b, int off, int len) throws IOException {
    			bos.write(b, off, len);
    		}
    	}
    }

2. 编写Filter

package com.hbzx.interceptor;
    
    import java.io.IOException;
    import java.io.OutputStream;
    
    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;
    
    import org.apache.commons.lang3.StringUtils;
    import org.springframework.http.MediaType;
    
    public class UrlImageFilter implements Filter {
    
    	@Override
    	public void destroy() {
    	}
    
    	@Override
    	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    		UrlResponseWrapper responseWrapper = new UrlResponseWrapper((HttpServletResponse) response);
    		chain.doFilter(request, responseWrapper);
    		String contentType = responseWrapper.getContentType();
    		byte[] content = responseWrapper.getResponseData();
    		if(StringUtils.isNotBlank(contentType) && (contentType.contains(MediaType.APPLICATION_JSON_VALUE) || contentType.contains(MediaType.TEXT_HTML_VALUE))) {
    			String str = new String(content);
    			str = StringUtils.replace(str, "xxxx", "aaaa");
    			content = str.getBytes();
    		}
    		OutputStream out = response.getOutputStream();
    		out.write(content);
    		out.flush();
    	}
    
    	@Override
    	public void init(FilterConfig arg0) throws ServletException {
    	}
    
    }

3. 在web.xml 中配置filter

<filter>
    		 <filter-name>urlFilter</filter-name>
    		 <filter-class>com.hbzx.interceptor.UrlImageFilter</filter-class>
    	</filter>
    	<filter-mapping>
    		<filter-name>urlFilter</filter-name>
    		<url-pattern>/*</url-pattern>
    	</filter-mapping>