cn.hutool.extra.servlet.multipart.MultipartRequestInputStream Maven / Gradle / Ivy
package cn.hutool.extra.servlet.multipart;
import java.io.BufferedInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
* Http请求解析流，提供了专门针对带文件的form表单的解析
* 来自Jodd
*
* @author jodd.org
*/
public class MultipartRequestInputStream extends BufferedInputStream {
public MultipartRequestInputStream(InputStream in) {
super(in);
}
/**
* 读取byte字节流，在末尾抛出异常
*
* @return byte
* @throws IOException
*/
public byte readByte() throws IOException {
int i = super.read();
if (i == -1) {
throw new IOException("End of HTTP request stream reached");
}
return (byte) i;
}
/**
* 跳过指定位数的 bytes.
*
* @param i 跳过的byte数
*/
public void skipBytes(int i) throws IOException {
long len = super.skip(i);
if (len != i) {
throw new IOException("Unable to skip data in HTTP request");
}
}
// ---------------------------------------------------------------- boundary
/** part部分边界 */
protected byte[] boundary;
/**
* 输入流中读取边界
*
* @return 边界
* @throws IOException
*/
public byte[] readBoundary() throws IOException {
ByteArrayOutputStream boundaryOutput = new ByteArrayOutputStream(1024);
byte b;
// skip optional whitespaces
while ((b = readByte()) <= ' ') {
}
boundaryOutput.write(b);
// now read boundary chars
while ((b = readByte()) != '\r') {
boundaryOutput.write(b);
}
if (boundaryOutput.size() == 0) {
throw new IOException("Problems with parsing request: invalid boundary");
}
skipBytes(1);
boundary = new byte[boundaryOutput.size() + 2];
System.arraycopy(boundaryOutput.toByteArray(), 0, boundary, 2, boundary.length - 2);
boundary[0] = '\r';
boundary[1] = '\n';
return boundary;
}
// ---------------------------------------------------------------- data header
protected UploadFileHeader lastHeader;
public UploadFileHeader getLastHeader() {
return lastHeader;
}
/**
* 从流中读取文件头部信息， 如果达到末尾则返回null
*
* @param encoding 字符集
* @return 头部信息， 如果达到末尾则返回null
* @throws IOException
*/
public UploadFileHeader readDataHeader(String encoding) throws IOException {
String dataHeader = readDataHeaderString(encoding);
if (dataHeader != null) {
lastHeader = new UploadFileHeader(dataHeader);
} else {
lastHeader = null;
}
return lastHeader;
}
protected String readDataHeaderString(String encoding) throws IOException {
ByteArrayOutputStream data = new ByteArrayOutputStream();
byte b;
while (true) {
// end marker byte on offset +0 and +2 must be 13
if ((b = readByte()) != '\r') {
data.write(b);
continue;
}
mark(4);
skipBytes(1);
int i = read();
if (i == -1) {
// reached end of stream
return null;
}
if (i == '\r') {
reset();
break;
}
reset();
data.write(b);
}
skipBytes(3);
return encoding == null ? data.toString() : data.toString(encoding);
}
// ---------------------------------------------------------------- copy
/**
* 全部字节流复制到out
*
* @param out 输出流
* @return 复制的字节数
* @throws IOException
*/
public int copy(OutputStream out) throws IOException {
int count = 0;
while (true) {
byte b = readByte();
if (isBoundary(b)) {
break;
}
out.write(b);
count++;
}
return count;
}
/**
* 复制字节流到out， 大于maxBytes或者文件末尾停止
*
* @param out 输出流
* @param limit 最大字节数
* @return 复制的字节数
* @throws IOException
*/
public int copy(OutputStream out, int limit) throws IOException {
int count = 0;
while (true) {
byte b = readByte();
if (isBoundary(b)) {
break;
}
out.write(b);
count++;
if (count > limit) {
break;
}
}
return count;
}
/**
* 跳过边界表示
*
* @return 跳过的字节数
*/
public int skipToBoundary() throws IOException {
int count = 0;
while (true) {
byte b = readByte();
count++;
if (isBoundary(b)) {
break;
}
}
return count;
}
/**
* @param b byte
* @return 是否为边界的标志
* @throws IOException
*/
public boolean isBoundary(byte b) throws IOException {
int boundaryLen = boundary.length;
mark(boundaryLen + 1);
int bpos = 0;
while (b == boundary[bpos]) {
b = readByte();
bpos++;
if (bpos == boundaryLen) {
return true; // boundary found!
}
}
reset();
return false;
}
}