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本篇內容介紹了“怎么解決在controller中無法二次讀取的問題”的有關知識，在實際案例的操作過程中，不少人都會遇到這樣的困境，接下來就讓小編帶領大家學習一下如何處理這些情況吧！希望大家仔細閱讀，能夠學有所成！
攔截器中讀取request參數,在controller中無法二次讀取
新建類
添加過濾器
使用攔截器時，controller中不能再次獲取body中的參數
解決辦法
1、獲取body信息
2、重新寫入
3、注冊過濾器
package com.ouyeelbuy.mc.common.base;
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.*;
/**
* @author robin.zhang
* @date $
* @description 解決在request的數據流只能讀取一次的問題
*/
public class RequestWrapper extends HttpServletRequestWrapper {
private final String body;
public RequestWrapper(HttpServletRequest request) {
super(request);
StringBuilder stringBuilder = new StringBuilder();
BufferedReader bufferedReader = null;
InputStream inputStream = null;
try {
inputStream = request.getInputStream();
if (inputStream != null) {
bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
char[] charBuffer = new char[128];
int bytesRead = -1;
while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
stringBuilder.append(charBuffer, 0, bytesRead);
}
} else {
stringBuilder.append("");
}
} catch (IOException ex) {
} finally {
if (inputStream != null) {
try {
inputStream.close();
}
catch (IOException e) {
e.printStackTrace();
}
}
if (bufferedReader != null) {
try {
bufferedReader.close();
}
catch (IOException e) {
e.printStackTrace();
}
}
}
body = stringBuilder.toString();
}
@Override
public ServletInputStream getInputStream() throws IOException {
final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes());
ServletInputStream servletInputStream = new ServletInputStream() {
@Override
public boolean isFinished() {
return false;
}
@Override
public boolean isReady() {
return false;
}
@Override
public void setReadListener(ReadListener readListener) {
}
@Override
public int read() throws IOException {
return byteArrayInputStream.read();
}
};
return servletInputStream;
}
@Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(this.getInputStream()));
}
public String getBody() {
return this.body;
}
}package com.ouyeelbuy.mc.common.filter;
import com.ouyeelbuy.mc.common.base.RequestWrapper;
import org.springframework.stereotype.Component;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
/**
* @author robin.zhang
* @date $
* @description 解決request數據流只能讀取一次的問題
*/
@Component
public class RequestFilter implements Filter{
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
ServletRequest requestWrapper = null;
if(servletRequest instanceof HttpServletRequest) {
requestWrapper = new RequestWrapper((HttpServletRequest) servletRequest);
}
if(requestWrapper == null) {
filterChain.doFilter(servletRequest, servletResponse);
} else {
filterChain.doFilter(requestWrapper, servletResponse);
}
}
@Override
public void destroy() {
}
}然后注冊這個過濾器到spring容器中，問題解決！
報錯信息：從報錯信息可以看出，io流已經關閉。這是由于攔截器讀取了body中的參數信息，導致controller不能再次讀取。
I/O error while reading input message; nested exception is java.io.IOException: Stream closed
在攔截器讀取到body信息后，再次將內容寫入
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.*;
import java.nio.charset.Charset;
/**
* 保存流
*/
public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {
private final byte[] body;
public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) {
super(request);
String sessionStream = getBodyString(request);
body = sessionStream.getBytes(Charset.forName("UTF-8"));
}
/**
* 獲取請求Body
*
* @param request
* @return
*/
public String getBodyString(final ServletRequest request) {
StringBuilder sb = new StringBuilder();
InputStream inputStream = null;
BufferedReader reader = null;
try {
inputStream = cloneInputStream(request.getInputStream());
reader = new BufferedReader(new InputStreamReader(inputStream, Charset.forName("UTF-8")));
String line = "";
while ((line = reader.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (inputStream != null) {
try {
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return sb.toString();
}
/**
* Description: 復制輸入流</br>
*
* @param inputStream
* @return</br>
*/
public InputStream cloneInputStream(ServletInputStream inputStream) {
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len;
try {
while ((len = inputStream.read(buffer)) > -1) {
byteArrayOutputStream.write(buffer, 0, len);
}
byteArrayOutputStream.flush();
} catch (IOException e) {
e.printStackTrace();
}
InputStream byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
return byteArrayInputStream;
}
@Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(getInputStream()));
}
@Override
public ServletInputStream getInputStream() throws IOException {
final ByteArrayInputStream bais = new ByteArrayInputStream(body);
return new ServletInputStream() {
@Override
public int read() throws IOException {
return bais.read();
}
@Override
public boolean isFinished() {
return false;
}
@Override
public boolean isReady() {
return false;
}
@Override
public void setReadListener(ReadListener readListener) {
}
};
}
}import org.springframework.core.annotation.Order;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
// 表示執行過濾順序，值越小，越先執行
@Order(1)
// 配置需要過濾的地址
@WebFilter(filterName = "bodyReaderFilter", urlPatterns = "/*")
public class BodyReaderFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
// System.out.println("--------------過濾器初始化------------");
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
// System.out.println("--------------執行過濾操作------------");
// 防止流讀取一次后就沒有了, 所以需要將流繼續寫出去
HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
ServletRequest requestWrapper = new BodyReaderHttpServletRequestWrapper(httpServletRequest);
filterChain.doFilter(requestWrapper, servletResponse);
}
@Override
public void destroy() {
// System.out.println("--------------過濾器銷毀------------");
}
}import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
@SpringBootApplication
@EnableFeignClients
@EnableDiscoveryClient
// 注冊過濾器注解
@ServletComponentScan
public class WebPlatformApplication {
public static void main(String[] args) {
SpringApplication.run(WebPlatformApplication.class);
}
}“怎么解決在controller中無法二次讀取的問題”的內容就介紹到這里了，感謝大家的閱讀。如果想了解更多行業相關的知識可以關注億速云網站，小編將為大家輸出更多高質量的實用文章！
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