有時候在開發過程中會有這樣一個場景,有時需要對返回的數據進行處理。比如加密啊,添加某些標記啊等等。這種情況我們可以通過過濾器去處理。
過濾器是什麼就不介紹了,百度一下,你就知道。
看看代碼吧:
返回值輸出代理類:這個類主要是爲了吧Response裏面的返回值獲取到,因爲直接Response沒有提供直接拿到返回值的方法。所以要通過代理來取得返回值
package com.channel.filter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.servlet.ServletOutputStream;
import javax.servlet.WriteListener;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
/**
* 返回值輸出代理類
*
* @Title: ResponseWrapper
* @Description:
* @author kokJuis
* @date 上午9:52:11
*/
public class ResponseWrapper extends HttpServletResponseWrapper
{
private ByteArrayOutputStream buffer;
private ServletOutputStream out;
public ResponseWrapper(HttpServletResponse httpServletResponse)
{
super(httpServletResponse);
buffer = new ByteArrayOutputStream();
out = new WrapperOutputStream(buffer);
}
@Override
public ServletOutputStream getOutputStream()
throws IOException
{
return out;
}
@Override
public void flushBuffer()
throws IOException
{
if (out != null)
{
out.flush();
}
}
public byte[] getContent()
throws IOException
{
flushBuffer();
return buffer.toByteArray();
}
class WrapperOutputStream extends ServletOutputStream
{
private ByteArrayOutputStream bos;
public WrapperOutputStream(ByteArrayOutputStream bos)
{
this.bos = bos;
}
@Override
public void write(int b)
throws IOException
{
bos.write(b);
}
@Override
public boolean isReady()
{
// TODO Auto-generated method stub
return false;
}
@Override
public void setWriteListener(WriteListener arg0)
{
// TODO Auto-generated method stub
}
}
}
過濾器類:
package com.channel.filter;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;
import com.channel.util.RsaEncryptUtil;
/**
* 返回值輸出過濾器,這裏用來加密返回值
*
* @Title: ResponseFilter
* @Description:
* @author kokJuis
* @date 上午9:52:42
*/
public class ResponseFilter implements Filter
{
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain)
throws IOException, ServletException
{
ResponseWrapper wrapperResponse = new ResponseWrapper((HttpServletResponse)response);//轉換成代理類
// 這裏只攔截返回,直接讓請求過去,如果在請求前有處理,可以在這裏處理
filterChain.doFilter(request, wrapperResponse);
byte[] content = wrapperResponse.getContent();//獲取返回值
//判斷是否有值
if (content.length > 0)
{
String str = new String(content, "UTF-8");
System.out.println("返回值:" + str);
String ciphertext = null;
try
{
//......根據需要處理返回值
}
catch (Exception e)
{
e.printStackTrace();
}
//把返回值輸出到客戶端
ServletOutputStream out = response.getOutputStream();
out.write(ciphertext.getBytes());
out.flush();
}
}
@Override
public void init(FilterConfig arg0)
throws ServletException
{
}
@Override
public void destroy()
{
}
}
配置很簡單:
spring boot:
/**
* 配置過濾器,這裏過濾器主要是對返回值做後繼處理
*
* @return
*/
@Bean
public FilterRegistrationBean someFilterRegistration()
{
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(new ResponseFilter());// 配置一個返回值加密過濾器
registration.addUrlPatterns("/*");
registration.addInitParameter("paramName", "paramValue");
registration.setName("responseFilter");
return registration;
}
spring mvc 下直接在web.xml下添加配置即可
<!-- 返回值過濾器 -->
<filter>
<filter-name>responseFilter</filter-name>
<filter-class>com.im.filter.ResponseFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>responseFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
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版權聲明:本文爲CSDN博主「Gogym」的原創文章,遵循 CC 4.0 BY-SA 版權協議,轉載請附上原文出處鏈接及本聲明。
原文鏈接:https://blog.csdn.net/kokjuis/article/details/77371324