标签：throws EntityUtils charset entity HttpEntity 工具 null final
EntityUtils 工具类
EntityUtils对象是org.apache.http.util下的一个工具类，用官方的解释是为HttpEntity对象提供的静态帮助类
package org.apache.http.util;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.nio.charset.UnsupportedCharsetException;
import org.apache.http.HeaderElement;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.entity.ContentType;
import org.apache.http.protocol.HTTP;
/**
* Static helpers for dealing with {@link HttpEntity}s.
*
* @since 4.0
*/
public final class EntityUtils {
private EntityUtils() {
}
/**
* Ensures that the entity content is fully consumed and the content stream, if exists,
* is closed. The process is done, <i>quietly</i> , without throwing any IOException.
*
* @param entity the entity to consume.
*
*
* @since 4.2
*/
public static void consumeQuietly(final HttpEntity entity) {
try {
consume(entity);
} catch (final IOException ignore) {
}
}
/**
* Ensures that the entity content is fully consumed and the content stream, if exists,
* is closed.
*
* @param entity the entity to consume.
* @throws IOException if an error occurs reading the input stream
*
* @since 4.1
*/
public static void consume(final HttpEntity entity) throws IOException {
if (entity == null) {
return;
}
if (entity.isStreaming()) {
final InputStream instream = entity.getContent();
if (instream != null) {
instream.close();
}
}
}
/**
* Updates an entity in a response by first consuming an existing entity, then setting the new one.
*
* @param response the response with an entity to update; must not be null.
* @param entity the entity to set in the response.
* @throws IOException if an error occurs while reading the input stream on the existing
* entity.
* @throws IllegalArgumentException if response is null.
*
* @since 4.3
*/
public static void updateEntity(
final HttpResponse response, final HttpEntity entity) throws IOException {
Args.notNull(response, "Response");
consume(response.getEntity());
response.setEntity(entity);
}
/**
* Read the contents of an entity and return it as a byte array.
*
* @param entity the entity to read from=
* @return byte array containing the entity content. May be null if
* {@link HttpEntity#getContent()} is null.
* @throws IOException if an error occurs reading the input stream
* @throws IllegalArgumentException if entity is null or if content length > Integer.MAX_VALUE
*/
public static byte[] toByteArray(final HttpEntity entity) throws IOException {
Args.notNull(entity, "Entity");
final InputStream instream = entity.getContent();
if (instream == null) {
return null;
}
try {
Args.check(entity.getContentLength() <= Integer.MAX_VALUE,
"HTTP entity too large to be buffered in memory");
int i = (int)entity.getContentLength();
if (i < 0) {
i = 4096;
}
final ByteArrayBuffer buffer = new ByteArrayBuffer(i);
final byte[] tmp = new byte[4096];
int l;
while((l = instream.read(tmp)) != -1) {
buffer.append(tmp, 0, l);
}
return buffer.toByteArray();
} finally {
instream.close();
}
}
/**
* Obtains character set of the entity, if known.
*
* @param entity must not be null
* @return the character set, or null if not found
* @throws ParseException if header elements cannot be parsed
* @throws IllegalArgumentException if entity is null
*
* @deprecated (4.1.3) use {@link ContentType#getOrDefault(HttpEntity)}
*/
@Deprecated
public static String getContentCharSet(final HttpEntity entity) throws ParseException {
Args.notNull(entity, "Entity");
String charset = null;
if (entity.getContentType() != null) {
final HeaderElement values[] = entity.getContentType().getElements();
if (values.length > 0) {
final NameValuePair param = values[0].getParameterByName("charset");
if (param != null) {
charset = param.getValue();
}
}
}
return charset;
}
/**
* Obtains MIME type of the entity, if known.
*
* @param entity must not be null
* @return the character set, or null if not found
* @throws ParseException if header elements cannot be parsed
* @throws IllegalArgumentException if entity is null
*
* @since 4.1
*
* @deprecated (4.1.3) use {@link ContentType#getOrDefault(HttpEntity)}
*/
@Deprecated
public static String getContentMimeType(final HttpEntity entity) throws ParseException {
Args.notNull(entity, "Entity");
String mimeType = null;
if (entity.getContentType() != null) {
final HeaderElement values[] = entity.getContentType().getElements();
if (values.length > 0) {
mimeType = values[0].getName();
}
}
return mimeType;
}
private static String toString(
final HttpEntity entity,
final ContentType contentType) throws IOException {
final InputStream instream = entity.getContent();
if (instream == null) {
return null;
}
try {
Args.check(entity.getContentLength() <= Integer.MAX_VALUE,
"HTTP entity too large to be buffered in memory");
int i = (int)entity.getContentLength();
if (i < 0) {
i = 4096;
}
Charset charset = null;
if (contentType != null) {
charset = contentType.getCharset();
if (charset == null) {
final ContentType defaultContentType = ContentType.getByMimeType(contentType.getMimeType());
charset = defaultContentType != null ? defaultContentType.getCharset() : null;
}
}
if (charset == null) {
charset = HTTP.DEF_CONTENT_CHARSET;
}
final Reader reader = new InputStreamReader(instream, charset);
final CharArrayBuffer buffer = new CharArrayBuffer(i);
final char[] tmp = new char[1024];
int l;
while((l = reader.read(tmp)) != -1) {
buffer.append(tmp, 0, l);
}
return buffer.toString();
} finally {
instream.close();
}
}
/**
* Get the entity content as a String, using the provided default character set
* if none is found in the entity.
* If defaultCharset is null, the default "ISO-8859-1" is used.
*
* @param entity must not be null
* @param defaultCharset character set to be applied if none found in the entity,
* or if the entity provided charset is invalid or not available.
* @return the entity content as a String. May be null if
* {@link HttpEntity#getContent()} is null.
* @throws ParseException if header elements cannot be parsed
* @throws IllegalArgumentException if entity is null or if content length > Integer.MAX_VALUE
* @throws IOException if an error occurs reading the input stream
* @throws java.nio.charset.UnsupportedCharsetException Thrown when the named entity's charset is not available in
* this instance of the Java virtual machine and no defaultCharset is provided.
*/
public static String toString(
final HttpEntity entity, final Charset defaultCharset) throws IOException, ParseException {
Args.notNull(entity, "Entity");
ContentType contentType = null;
try {
contentType = ContentType.get(entity);
} catch (final UnsupportedCharsetException ex) {
if (defaultCharset == null) {
throw new UnsupportedEncodingException(ex.getMessage());
}
}
if (contentType != null) {
if (contentType.getCharset() == null) {
contentType = contentType.withCharset(defaultCharset);
}
} else {
contentType = ContentType.DEFAULT_TEXT.withCharset(defaultCharset);
}
return toString(entity, contentType);
}
/**
* Get the entity content as a String, using the provided default character set
* if none is found in the entity.
* If defaultCharset is null, the default "ISO-8859-1" is used.
*
* @param entity must not be null
* @param defaultCharset character set to be applied if none found in the entity
* @return the entity content as a String. May be null if
* {@link HttpEntity#getContent()} is null.
* @throws ParseException if header elements cannot be parsed
* @throws IllegalArgumentException if entity is null or if content length > Integer.MAX_VALUE
* @throws IOException if an error occurs reading the input stream
* @throws java.nio.charset.UnsupportedCharsetException Thrown when the named charset is not available in
* this instance of the Java virtual machine
*/
public static String toString(
final HttpEntity entity, final String defaultCharset) throws IOException, ParseException {
return toString(entity, defaultCharset != null ? Charset.forName(defaultCharset) : null);
}
/**
* Read the contents of an entity and return it as a String.
* The content is converted using the character set from the entity (if any),
* failing that, "ISO-8859-1" is used.
*
* @param entity the entity to convert to a string; must not be null
* @return String containing the content.
* @throws ParseException if header elements cannot be parsed
* @throws IllegalArgumentException if entity is null or if content length > Integer.MAX_VALUE
* @throws IOException if an error occurs reading the input stream
* @throws java.nio.charset.UnsupportedCharsetException Thrown when the named charset is not available in
* this instance of the Java virtual machine
*/
public static String toString(final HttpEntity entity) throws IOException, ParseException {
Args.notNull(entity, "Entity");
return toString(entity, ContentType.get(entity));
}
}
EntityUtils.toString(entity)处理字符集编码问题
标签：throws,EntityUtils,charset,entity,HttpEntity,工具,null,final 来源： https://blog.csdn.net/weixin_42408447/article/details/121035705
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