springboot对压缩请求的处理
最近对接银联需求，为了节省带宽，需要对报文进行压缩处理。但是使用springboot自带的压缩设置不起作用：
server.compression.enabled=true server.compression.mime-types=application/javascript,text/css,application/json,application/xml,text/html,text/xml,text/plain server.compression.compressionMinSize=10
server.compression.enabled：表示是否开启压缩，默认开启，true:开启，false:不开启server.compression.mime-types：压缩的内容的类型，有xml,json，html等格式server.compression.compressionMinSize：开启压缩数据最小长度，单位为字节，默认是2048字节源码如下：
public class Compression {
private boolean enabled = false;
private String[] mimeTypes = new String[]{"text/html", "text/xml", "text/plain", "text/css", "text/javascript", "application/javascript", "application/json", "application/xml"};
private String[] excludedUserAgents = null;
private int minResponseSize = 2048;
}一、Tomcat设置压缩原理
tomcat压缩是对响应报文进行压缩，当请求头中存在accept-encoding时，如果Tomcat设置了压缩，则会在响应时对数据进行压缩。
tomcat压缩源码是在Http11Processor中设置的：
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public class Http11Processor extends AbstractProcessor {
private boolean useCompression() {
// Check if browser support gzip encoding
MessageBytes acceptEncodingMB =
request.getMimeHeaders().getValue("accept-encoding");
if ((acceptEncodingMB == null)-->当请求头没有这个字段是不进行压缩
|| (acceptEncodingMB.indexOf("gzip") == -1)) {
return false;
}
// If force mode, always compress (test purposes only)
if (compressionLevel == 2) {
return true;
}
// Check for incompatible Browser
if (noCompressionUserAgents != null) {
MessageBytes userAgentValueMB =
request.getMimeHeaders().getValue("user-agent");
if(userAgentValueMB != null) {
String userAgentValue = userAgentValueMB.toString();
if (noCompressionUserAgents.matcher(userAgentValue).matches()) {
return false;
}
}
}
return true;
}
}二、银联报文压缩
作为发卡机构，银联报文请求报文是压缩的，且报文头中不存在accept-encoding字段，无法直接使用tomcat配置进行压缩解压。
需要单独处理这种请求
@RestController
@RequestMapping("/user")
public class UserController {
private static final Logger logger = LoggerFactory.getLogger(UserController.class);
/**
*
* application/xml格式报文
* */
@PostMapping(path = "/test", produces = MediaType.APPLICATION_XML_VALUE, consumes = MediaType.APPLICATION_XML_VALUE)
public void getUserInfoById(HttpServletRequest request, HttpServletResponse response) throws IOException {
String requestBody;
String resultBody="hello,wolrd";
byte[] returnByte;
if (StringUtils.isNoneEmpty(request.getHeader("Content-encoding"))) {
logger.info("报文压缩，需要进行解压");
//业务处理
//返回报文也同样需要进行压缩处理
assemleResponse(request,response,resultBody);
}
}
public static void assemleResponse(HttpServletRequest request, HttpServletResponse response,String resultBody) throws IOException {
response.setHeader("Content-Type","application/xml;charset=UTF-8");
response.setHeader("Content-Encoding","gzip");
byte[] returnByte=GzipUtil.compress(resultBody);
OutputStream outputStream=response.getOutputStream();
outputStream.write(returnByte);
}
}public class GzipUtil {
public static String uncompress(byte[] bytes){
if (bytes == null || bytes.length == 0) {
return null;
}
String requestBody=null;
ByteArrayInputStream byteArrayInputStream=new ByteArrayInputStream(bytes);
GZIPInputStream gzipInputStream = null;
try {
gzipInputStream = new GZIPInputStream(byteArrayInputStream);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int temp;
while ((temp = gzipInputStream.read(buffer)) != -1) {
byteArrayOutputStream.write(buffer, 0, temp);
}
requestBody = new String(byteArrayOutputStream.toByteArray(), StandardCharsets.UTF_8);
} catch (IOException e) {
e.printStackTrace();
}
return requestBody;
}
public static String uncompress(HttpServletRequest request){
String requestBody=null;
int length = request.getContentLength();
try {
BufferedInputStream bufferedInputStream = new BufferedInputStream(request.getInputStream());
GZIPInputStream gzipInputStream = new GZIPInputStream(bufferedInputStream);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int temp;
while ((temp = gzipInputStream.read(buffer)) != -1) {
byteArrayOutputStream.write(buffer, 0, temp);
}
requestBody = new String(byteArrayOutputStream.toByteArray(), StandardCharsets.UTF_8);
} catch (IOException e) {
e.printStackTrace();
}
return requestBody;
}
public static byte[] compress(String src){
if (src == null || src.length() == 0) {
return null;
}
ByteArrayOutputStream byteArrayOutputStream=new ByteArrayOutputStream();
try {
GZIPOutputStream gzipOutputStream=new GZIPOutputStream(byteArrayOutputStream);
gzipOutputStream.write(src.getBytes(StandardCharsets.UTF_8));
gzipOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
byte[] bytes=byteArrayOutputStream.toByteArray();
return bytes;
}
}补充：java springbooot使用gzip压缩字符串
import lombok.extern.slf4j.Slf4j;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;
/**
* effect:压缩/解压 字符串
*/
@Slf4j
public class CompressUtils {
/**
* effect 使用gzip压缩字符串
* @param str 要压缩的字符串
* @return
*/
public static String compress(String str) {
if (str == null || str.length() == 0) {
return str;
}
ByteArrayOutputStream out = new ByteArrayOutputStream();
GZIPOutputStream gzip = null;
try {
gzip = new GZIPOutputStream(out);
gzip.write(str.getBytes());
} catch (IOException e) {
log.error("",e);
} finally {
if (gzip != null) {
try {
gzip.close();
} catch (IOException e) {
log.error("",e);
}
}
}
return new sun.misc.BASE64Encoder().encode(out.toByteArray());
// return str;
}
/**
* effect 使用gzip解压缩
*
* @param str 压缩字符串
* @return
*/
public static String uncompress(String str) {
if (str == null) {
return null;
}
ByteArrayOutputStream out = new ByteArrayOutputStream();
ByteArrayInputStream in = null;
GZIPInputStream ginzip = null;
byte[] compressed = null;
String decompressed = null;
try {
compressed = new sun.misc.BASE64Decoder().decodeBuffer(str);
in = new ByteArrayInputStream(compressed);
ginzip = new GZIPInputStream(in);
byte[] buffer = new byte[1024];
int offset = -1;
while ((offset = ginzip.read(buffer)) != -1) {
out.write(buffer, 0, offset);
}
decompressed = out.toString();
} catch (IOException e) {
log.error("",e);
} finally {
if (ginzip != null) {
try {
ginzip.close();
} catch (IOException e) {
}
}
if (in != null) {
try {
in.close();
} catch (IOException e) {
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
}
}
}
return decompressed;
}
} 
