spring MimeType 源码
spring MimeType 代码
文件路径：/spring-core/src/main/java/org/springframework/util/MimeType.java
/*
* Copyright 2002-2022 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.util;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.nio.charset.Charset;
import java.util.BitSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Locale;
import java.util.Map;
import java.util.TreeSet;
import org.springframework.lang.Nullable;
/**
* Represents a MIME Type, as originally defined in RFC 2046 and subsequently
* used in other Internet protocols including HTTP.
*
* <p>This class, however, does not contain support for the q-parameters used
* in HTTP content negotiation. Those can be found in the subclass
* {@code org.springframework.http.MediaType} in the {@code spring-web} module.
*
* <p>Consists of a {@linkplain #getType() type} and a {@linkplain #getSubtype() subtype}.
* Also has functionality to parse MIME Type values from a {@code String} using
* {@link #valueOf(String)}. For more parsing options see {@link MimeTypeUtils}.
*
* @author Arjen Poutsma
* @author Juergen Hoeller
* @author Rossen Stoyanchev
* @author Sam Brannen
* @since 4.0
* @see MimeTypeUtils
*/
public class MimeType implements Comparable<MimeType>, Serializable {
private static final long serialVersionUID = 4085923477777865903L;
protected static final String WILDCARD_TYPE = "*";
private static final String PARAM_CHARSET = "charset";
private static final BitSet TOKEN;
static {
// variable names refer to RFC 2616, section 2.2
BitSet ctl = new BitSet(128);
for (int i = 0; i <= 31; i++) {
ctl.set(i);
}
ctl.set(127);
BitSet separators = new BitSet(128);
separators.set('(');
separators.set(')');
separators.set('<');
separators.set('>');
separators.set('@');
separators.set(',');
separators.set(';');
separators.set(':');
separators.set('\\');
separators.set('\"');
separators.set('/');
separators.set('[');
separators.set(']');
separators.set('?');
separators.set('=');
separators.set('{');
separators.set('}');
separators.set(' ');
separators.set('\t');
TOKEN = new BitSet(128);
TOKEN.set(0, 128);
TOKEN.andNot(ctl);
TOKEN.andNot(separators);
}
private final String type;
private final String subtype;
private final Map<String, String> parameters;
@Nullable
private transient Charset resolvedCharset;
@Nullable
private volatile String toStringValue;
/**
* Create a new {@code MimeType} for the given primary type.
* <p>The {@linkplain #getSubtype() subtype} is set to <code>"*"</code>,
* and the parameters are empty.
* @param type the primary type
* @throws IllegalArgumentException if any of the parameters contains illegal characters
*/
public MimeType(String type) {
this(type, WILDCARD_TYPE);
}
/**
* Create a new {@code MimeType} for the given primary type and subtype.
* <p>The parameters are empty.
* @param type the primary type
* @param subtype the subtype
* @throws IllegalArgumentException if any of the parameters contains illegal characters
*/
public MimeType(String type, String subtype) {
this(type, subtype, Collections.emptyMap());
}
/**
* Create a new {@code MimeType} for the given type, subtype, and character set.
* @param type the primary type
* @param subtype the subtype
* @param charset the character set
* @throws IllegalArgumentException if any of the parameters contains illegal characters
*/
public MimeType(String type, String subtype, Charset charset) {
this(type, subtype, Collections.singletonMap(PARAM_CHARSET, charset.name()));
this.resolvedCharset = charset;
}
/**
* Copy-constructor that copies the type, subtype, parameters of the given {@code MimeType},
* and allows to set the specified character set.
* @param other the other MimeType
* @param charset the character set
* @throws IllegalArgumentException if any of the parameters contains illegal characters
* @since 4.3
*/
public MimeType(MimeType other, Charset charset) {
this(other.getType(), other.getSubtype(), addCharsetParameter(charset, other.getParameters()));
this.resolvedCharset = charset;
}
/**
* Copy-constructor that copies the type and subtype of the given {@code MimeType},
* and allows for different parameter.
* @param other the other MimeType
* @param parameters the parameters (may be {@code null})
* @throws IllegalArgumentException if any of the parameters contains illegal characters
*/
public MimeType(MimeType other, @Nullable Map<String, String> parameters) {
this(other.getType(), other.getSubtype(), parameters);
}
/**
* Create a new {@code MimeType} for the given type, subtype, and parameters.
* @param type the primary type
* @param subtype the subtype
* @param parameters the parameters (may be {@code null})
* @throws IllegalArgumentException if any of the parameters contains illegal characters
*/
public MimeType(String type, String subtype, @Nullable Map<String, String> parameters) {
Assert.hasLength(type, "'type' must not be empty");
Assert.hasLength(subtype, "'subtype' must not be empty");
checkToken(type);
checkToken(subtype);
this.type = type.toLowerCase(Locale.ENGLISH);
this.subtype = subtype.toLowerCase(Locale.ENGLISH);
if (!CollectionUtils.isEmpty(parameters)) {
Map<String, String> map = new LinkedCaseInsensitiveMap<>(parameters.size(), Locale.ENGLISH);
parameters.forEach((parameter, value) -> {
checkParameters(parameter, value);
map.put(parameter, value);
});
this.parameters = Collections.unmodifiableMap(map);
}
else {
this.parameters = Collections.emptyMap();
}
}
/**
* Copy-constructor that copies the type, subtype and parameters of the given {@code MimeType},
* skipping checks performed in other constructors.
* @param other the other MimeType
* @since 5.3
*/
protected MimeType(MimeType other) {
this.type = other.type;
this.subtype = other.subtype;
this.parameters = other.parameters;
this.resolvedCharset = other.resolvedCharset;
this.toStringValue = other.toStringValue;
}
/**
* Checks the given token string for illegal characters, as defined in RFC 2616,
* section 2.2.
* @throws IllegalArgumentException in case of illegal characters
* @see <a href="https://tools.ietf.org/html/rfc2616#section-2.2">HTTP 1.1, section 2.2</a>
*/
private void checkToken(String token) {
for (int i = 0; i < token.length(); i++) {
char ch = token.charAt(i);
if (!TOKEN.get(ch)) {
throw new IllegalArgumentException("Invalid token character '" + ch + "' in token \"" + token + "\"");
}
}
}
protected void checkParameters(String parameter, String value) {
Assert.hasLength(parameter, "'parameter' must not be empty");
Assert.hasLength(value, "'value' must not be empty");
checkToken(parameter);
if (PARAM_CHARSET.equals(parameter)) {
if (this.resolvedCharset == null) {
this.resolvedCharset = Charset.forName(unquote(value));
}
}
else if (!isQuotedString(value)) {
checkToken(value);
}
}
private boolean isQuotedString(String s) {
if (s.length() < 2) {
return false;
}
else {
return ((s.startsWith("\"") && s.endsWith("\"")) || (s.startsWith("'") && s.endsWith("'")));
}
}
protected String unquote(String s) {
return (isQuotedString(s) ? s.substring(1, s.length() - 1) : s);
}
/**
* Indicates whether the {@linkplain #getType() type} is the wildcard character
* <code>*</code> or not.
*/
public boolean isWildcardType() {
return WILDCARD_TYPE.equals(getType());
}
/**
* Indicates whether the {@linkplain #getSubtype() subtype} is the wildcard
* character <code>*</code> or the wildcard character followed by a suffix
* (e.g. <code>*+xml</code>).
* @return whether the subtype is a wildcard
*/
public boolean isWildcardSubtype() {
return WILDCARD_TYPE.equals(getSubtype()) || getSubtype().startsWith("*+");
}
/**
* Indicates whether this MIME Type is concrete, i.e. whether neither the type
* nor the subtype is a wildcard character <code>*</code>.
* @return whether this MIME Type is concrete
*/
public boolean isConcrete() {
return !isWildcardType() && !isWildcardSubtype();
}
/**
* Return the primary type.
*/
public String getType() {
return this.type;
}
/**
* Return the subtype.
*/
public String getSubtype() {
return this.subtype;
}
/**
* Return the subtype suffix as defined in RFC 6839.
* @since 5.3
*/
@Nullable
public String getSubtypeSuffix() {
int suffixIndex = this.subtype.lastIndexOf('+');
if (suffixIndex != -1 && this.subtype.length() > suffixIndex) {
return this.subtype.substring(suffixIndex + 1);
}
return null;
}
/**
* Return the character set, as indicated by a {@code charset} parameter, if any.
* @return the character set, or {@code null} if not available
* @since 4.3
*/
@Nullable
public Charset getCharset() {
return this.resolvedCharset;
}
/**
* Return a generic parameter value, given a parameter name.
* @param name the parameter name
* @return the parameter value, or {@code null} if not present
*/
@Nullable
public String getParameter(String name) {
return this.parameters.get(name);
}
/**
* Return all generic parameter values.
* @return a read-only map (possibly empty, never {@code null})
*/
public Map<String, String> getParameters() {
return this.parameters;
}
/**
* Indicate whether this MIME Type includes the given MIME Type.
* <p>For instance, {@code text/*} includes {@code text/plain} and {@code text/html},
* and {@code application/*+xml} includes {@code application/soap+xml}, etc.
* This method is <b>not</b> symmetric.
* @param other the reference MIME Type with which to compare
* @return {@code true} if this MIME Type includes the given MIME Type;
* {@code false} otherwise
*/
public boolean includes(@Nullable MimeType other) {
if (other == null) {
return false;
}
if (isWildcardType()) {
// */* includes anything
return true;
}
else if (getType().equals(other.getType())) {
if (getSubtype().equals(other.getSubtype())) {
return true;
}
if (isWildcardSubtype()) {
// Wildcard with suffix, e.g. application/*+xml
int thisPlusIdx = getSubtype().lastIndexOf('+');
if (thisPlusIdx == -1) {
return true;
}
else {
// application/*+xml includes application/soap+xml
int otherPlusIdx = other.getSubtype().lastIndexOf('+');
if (otherPlusIdx != -1) {
String thisSubtypeNoSuffix = getSubtype().substring(0, thisPlusIdx);
String thisSubtypeSuffix = getSubtype().substring(thisPlusIdx + 1);
String otherSubtypeSuffix = other.getSubtype().substring(otherPlusIdx + 1);
if (thisSubtypeSuffix.equals(otherSubtypeSuffix) && WILDCARD_TYPE.equals(thisSubtypeNoSuffix)) {
return true;
}
}
}
}
}
return false;
}
/**
* Indicate whether this MIME Type is compatible with the given MIME Type.
* <p>For instance, {@code text/*} is compatible with {@code text/plain},
* {@code text/html}, and vice versa. In effect, this method is similar to
* {@link #includes}, except that it <b>is</b> symmetric.
* @param other the reference MIME Type with which to compare
* @return {@code true} if this MIME Type is compatible with the given MIME Type;
* {@code false} otherwise
*/
public boolean isCompatibleWith(@Nullable MimeType other) {
if (other == null) {
return false;
}
if (isWildcardType() || other.isWildcardType()) {
return true;
}
else if (getType().equals(other.getType())) {
if (getSubtype().equals(other.getSubtype())) {
return true;
}
if (isWildcardSubtype() || other.isWildcardSubtype()) {
String thisSuffix = getSubtypeSuffix();
String otherSuffix = other.getSubtypeSuffix();
if (getSubtype().equals(WILDCARD_TYPE) || other.getSubtype().equals(WILDCARD_TYPE)) {
return true;
}
else if (isWildcardSubtype() && thisSuffix != null) {
return (thisSuffix.equals(other.getSubtype()) || thisSuffix.equals(otherSuffix));
}
else if (other.isWildcardSubtype() && otherSuffix != null) {
return (this.getSubtype().equals(otherSuffix) || otherSuffix.equals(thisSuffix));
}
}
}
return false;
}
/**
* Similar to {@link #equals(Object)} but based on the type and subtype
* only, i.e. ignoring parameters.
* @param other the other mime type to compare to
* @return whether the two mime types have the same type and subtype
* @since 5.1.4
*/
public boolean equalsTypeAndSubtype(@Nullable MimeType other) {
if (other == null) {
return false;
}
return this.type.equalsIgnoreCase(other.type) && this.subtype.equalsIgnoreCase(other.subtype);
}
/**
* Unlike {@link Collection#contains(Object)} which relies on
* {@link MimeType#equals(Object)}, this method only checks the type and the
* subtype, but otherwise ignores parameters.
* @param mimeTypes the list of mime types to perform the check against
* @return whether the list contains the given mime type
* @since 5.1.4
*/
public boolean isPresentIn(Collection<? extends MimeType> mimeTypes) {
for (MimeType mimeType : mimeTypes) {
if (mimeType.equalsTypeAndSubtype(this)) {
return true;
}
}
return false;
}
@Override
public boolean equals(@Nullable Object other) {
if (this == other) {
return true;
}
if (!(other instanceof MimeType otherType)) {
return false;
}
return (this.type.equalsIgnoreCase(otherType.type) &&
this.subtype.equalsIgnoreCase(otherType.subtype) &&
parametersAreEqual(otherType));
}
/**
* Determine if the parameters in this {@code MimeType} and the supplied
* {@code MimeType} are equal, performing case-insensitive comparisons
* for {@link Charset Charsets}.
* @since 4.2
*/
private boolean parametersAreEqual(MimeType other) {
if (this.parameters.size() != other.parameters.size()) {
return false;
}
for (Map.Entry<String, String> entry : this.parameters.entrySet()) {
String key = entry.getKey();
if (!other.parameters.containsKey(key)) {
return false;
}
if (PARAM_CHARSET.equals(key)) {
if (!ObjectUtils.nullSafeEquals(getCharset(), other.getCharset())) {
return false;
}
}
else if (!ObjectUtils.nullSafeEquals(entry.getValue(), other.parameters.get(key))) {
return false;
}
}
return true;
}
@Override
public int hashCode() {
int result = this.type.hashCode();
result = 31 * result + this.subtype.hashCode();
result = 31 * result + this.parameters.hashCode();
return result;
}
@Override
public String toString() {
String value = this.toStringValue;
if (value == null) {
StringBuilder builder = new StringBuilder();
appendTo(builder);
value = builder.toString();
this.toStringValue = value;
}
return value;
}
protected void appendTo(StringBuilder builder) {
builder.append(this.type);
builder.append('/');
builder.append(this.subtype);
appendTo(this.parameters, builder);
}
private void appendTo(Map<String, String> map, StringBuilder builder) {
map.forEach((key, val) -> {
builder.append(';');
builder.append(key);
builder.append('=');
builder.append(val);
});
}
/**
* Compares this MIME Type to another alphabetically.
* @param other the MIME Type to compare to
*/
@Override
public int compareTo(MimeType other) {
int comp = getType().compareToIgnoreCase(other.getType());
if (comp != 0) {
return comp;
}
comp = getSubtype().compareToIgnoreCase(other.getSubtype());
if (comp != 0) {
return comp;
}
comp = getParameters().size() - other.getParameters().size();
if (comp != 0) {
return comp;
}
TreeSet<String> thisAttributes = new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
thisAttributes.addAll(getParameters().keySet());
TreeSet<String> otherAttributes = new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
otherAttributes.addAll(other.getParameters().keySet());
Iterator<String> thisAttributesIterator = thisAttributes.iterator();
Iterator<String> otherAttributesIterator = otherAttributes.iterator();
while (thisAttributesIterator.hasNext()) {
String thisAttribute = thisAttributesIterator.next();
String otherAttribute = otherAttributesIterator.next();
comp = thisAttribute.compareToIgnoreCase(otherAttribute);
if (comp != 0) {
return comp;
}
if (PARAM_CHARSET.equals(thisAttribute)) {
Charset thisCharset = getCharset();
Charset otherCharset = other.getCharset();
if (thisCharset != otherCharset) {
if (thisCharset == null) {
return -1;
}
if (otherCharset == null) {
return 1;
}
comp = thisCharset.compareTo(otherCharset);
if (comp != 0) {
return comp;
}
}
}
else {
String thisValue = getParameters().get(thisAttribute);
String otherValue = other.getParameters().get(otherAttribute);
if (otherValue == null) {
otherValue = "";
}
comp = thisValue.compareTo(otherValue);
if (comp != 0) {
return comp;
}
}
}
return 0;
}
/**
* Indicates whether this {@code MimeType} is more specific than the given
* type.
* <ol>
* <li>if this mime type has a {@linkplain #isWildcardType() wildcard type},
* and the other does not, then this method returns {@code false}.</li>
* <li>if this mime type does not have a {@linkplain #isWildcardType() wildcard type},
* and the other does, then this method returns {@code true}.</li>
* <li>if this mime type has a {@linkplain #isWildcardType() wildcard type},
* and the other does not, then this method returns {@code false}.</li>
* <li>if this mime type does not have a {@linkplain #isWildcardType() wildcard type},
* and the other does, then this method returns {@code true}.</li>
* <li>if the two mime types have identical {@linkplain #getType() type} and
* {@linkplain #getSubtype() subtype}, then the mime type with the most
* parameters is more specific than the other.</li>
* <li>Otherwise, this method returns {@code false}.</li>
* </ol>
* @param other the {@code MimeType} to be compared
* @return the result of the comparison
* @since 6.0
* @see #isLessSpecific(MimeType)
* @see <a href="https://tools.ietf.org/html/rfc7231#section-5.3.2">HTTP 1.1: Semantics
* and Content, section 5.3.2</a>
*/
public boolean isMoreSpecific(MimeType other) {
Assert.notNull(other, "Other must not be null");
boolean thisWildcard = isWildcardType();
boolean otherWildcard = other.isWildcardType();
if (thisWildcard && !otherWildcard) { // */* > audio/*
return false;
}
else if (!thisWildcard && otherWildcard) { // audio/* < */*
return true;
}
else {
boolean thisWildcardSubtype = isWildcardSubtype();
boolean otherWildcardSubtype = other.isWildcardSubtype();
if (thisWildcardSubtype && !otherWildcardSubtype) { // audio/* > audio/basic
return false;
}
else if (!thisWildcardSubtype && otherWildcardSubtype) { // audio/basic < audio/*
return true;
}
else if (getType().equals(other.getType()) && getSubtype().equals(other.getSubtype())) {
int paramsSize1 = getParameters().size();
int paramsSize2 = other.getParameters().size();
return paramsSize1 > paramsSize2;
}
else {
return false;
}
}
}
/**
* Indicates whether this {@code MimeType} is more less than the given type.
* <ol>
* <li>if this mime type has a {@linkplain #isWildcardType() wildcard type},
* and the other does not, then this method returns {@code true}.</li>
* <li>if this mime type does not have a {@linkplain #isWildcardType() wildcard type},
* and the other does, then this method returns {@code false}.</li>
* <li>if this mime type has a {@linkplain #isWildcardType() wildcard type},
* and the other does not, then this method returns {@code true}.</li>
* <li>if this mime type does not have a {@linkplain #isWildcardType() wildcard type},
* and the other does, then this method returns {@code false}.</li>
* <li>if the two mime types have identical {@linkplain #getType() type} and
* {@linkplain #getSubtype() subtype}, then the mime type with the least
* parameters is less specific than the other.</li>
* <li>Otherwise, this method returns {@code false}.</li>
* </ol>
* @param other the {@code MimeType} to be compared
* @return the result of the comparison
* @since 6.0
* @see #isMoreSpecific(MimeType)
* @see <a href="https://tools.ietf.org/html/rfc7231#section-5.3.2">HTTP 1.1: Semantics
* and Content, section 5.3.2</a>
*/
public boolean isLessSpecific(MimeType other) {
Assert.notNull(other, "Other must not be null");
return other.isMoreSpecific(this);
}
private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException {
// Rely on default serialization, just initialize state after deserialization.
ois.defaultReadObject();
// Initialize transient fields.
String charsetName = getParameter(PARAM_CHARSET);
if (charsetName != null) {
this.resolvedCharset = Charset.forName(unquote(charsetName));
}
}
/**
* Parse the given String value into a {@code MimeType} object,
* with this method name following the 'valueOf' naming convention
* (as supported by {@link org.springframework.core.convert.ConversionService}.
* @see MimeTypeUtils#parseMimeType(String)
*/
public static MimeType valueOf(String value) {
return MimeTypeUtils.parseMimeType(value);
}
private static Map<String, String> addCharsetParameter(Charset charset, Map<String, String> parameters) {
Map<String, String> map = new LinkedHashMap<>(parameters);
map.put(PARAM_CHARSET, charset.name());
return map;
}
/**
* Comparator to sort {@link MimeType MimeTypes} in order of specificity.
*
* @param <T> the type of mime types that may be compared by this comparator
* @deprecated As of 6.0, with no direct replacement
*/
@Deprecated
public static class SpecificityComparator<T extends MimeType> implements Comparator<T> {
@Override
public int compare(T mimeType1, T mimeType2) {
if (mimeType1.isWildcardType() && !mimeType2.isWildcardType()) { // */* < audio/*
return 1;
}
else if (mimeType2.isWildcardType() && !mimeType1.isWildcardType()) { // audio/* > */*
return -1;
}
else if (!mimeType1.getType().equals(mimeType2.getType())) { // audio/basic == text/html
return 0;
}
else { // mediaType1.getType().equals(mediaType2.getType())
if (mimeType1.isWildcardSubtype() && !mimeType2.isWildcardSubtype()) { // audio/* < audio/basic
return 1;
}
else if (mimeType2.isWildcardSubtype() && !mimeType1.isWildcardSubtype()) { // audio/basic > audio/*
return -1;
}
else if (!mimeType1.getSubtype().equals(mimeType2.getSubtype())) { // audio/basic == audio/wave
return 0;
}
else { // mediaType2.getSubtype().equals(mediaType2.getSubtype())
return compareParameters(mimeType1, mimeType2);
}
}
}
protected int compareParameters(T mimeType1, T mimeType2) {
int paramsSize1 = mimeType1.getParameters().size();
int paramsSize2 = mimeType2.getParameters().size();
return Integer.compare(paramsSize2, paramsSize1); // audio/basic;level=1 < audio/basic
}
}
}
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