RequestMapping.md

RequestMapping

RequestMapping.java

package org.springframework.web.bind.annotation;

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Mapping
public @interface RequestMapping {

	String name() default "";

	@AliasFor("path")
	String[] value() default {};

	@AliasFor("value")
	String[] path() default {};

	RequestMethod[] method() default {};

	String[] params() default {};

	String[] headers() default {};

	String[] consumes() default {};

	String[] produces() default {};

}

• 这是我们在使用SpringMVC时最常用的注解，用于标记一个类和方法能够处理某个HTTP请求。
• @Mapping注解暂时没看到哪儿使用，// TODO。
• 注解显然是会被反射拿来使用的。
• 这个注解的每个属性都会被封装到一个RequestCondition实例中。
• 整个注解会被封装到一个RequestMappingInfo实例中。

RequestCondition.java

package org.springframework.web.servlet.mvc.condition;
//请求条件
public interface RequestCondition<T> {

	T combine(T other);

	T getMatchingCondition(HttpServletRequest request);

	int compareTo(T other, HttpServletRequest request);

}

AbstractRequestCondition.java

package org.springframework.web.servlet.mvc.condition;

public abstract class AbstractRequestCondition<T extends AbstractRequestCondition<T>> implements RequestCondition<T> {
	//同一对象或同一个类型，content相同返回true
	@Override
	public boolean equals(Object obj) {
		if (this == obj) {
			return true;
		}
		if (obj != null && getClass() == obj.getClass()) {
			AbstractRequestCondition<?> other = (AbstractRequestCondition<?>) obj;
			return getContent().equals(other.getContent());
		}
		return false;
	}
	//获取内容的hashcode
	@Override
	public int hashCode() {
		return getContent().hashCode();
	}
	//[内容+连接符+内容]
	@Override
	public String toString() {
		StringBuilder builder = new StringBuilder("[");
		for (Iterator<?> iterator = getContent().iterator(); iterator.hasNext();) {
			Object expression = iterator.next();
			builder.append(expression.toString());
			if (iterator.hasNext()) {
				builder.append(getToStringInfix());
			}
		}
		builder.append("]");
		return builder.toString();
	}

	public boolean isEmpty() {
		return getContent().isEmpty();
	}

	protected abstract Collection<?> getContent();

	protected abstract String getToStringInfix();

}

PatternsRequestCondition.java

package org.springframework.web.servlet.mvc.condition;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import javax.servlet.http.HttpServletRequest;

import org.springframework.util.AntPathMatcher;
import org.springframework.util.PathMatcher;
import org.springframework.util.StringUtils;
import org.springframework.web.util.UrlPathHelper;

public final class PatternsRequestCondition extends AbstractRequestCondition<PatternsRequestCondition> {

	private final Set<String> patterns;

	private final UrlPathHelper pathHelper;

	private final PathMatcher pathMatcher;

	private final boolean useSuffixPatternMatch;

	private final boolean useTrailingSlashMatch;

	private final List<String> fileExtensions = new ArrayList<String>();

	public PatternsRequestCondition(String... patterns) {
		this(asList(patterns), null, null, true, true, null);
	}

	public PatternsRequestCondition(String[] patterns, UrlPathHelper urlPathHelper, PathMatcher pathMatcher,
			boolean useSuffixPatternMatch, boolean useTrailingSlashMatch) {

		this(asList(patterns), urlPathHelper, pathMatcher, useSuffixPatternMatch, useTrailingSlashMatch, null);
	}

	public PatternsRequestCondition(String[] patterns, UrlPathHelper urlPathHelper,
			PathMatcher pathMatcher, boolean useSuffixPatternMatch, boolean useTrailingSlashMatch,
			List<String> fileExtensions) {

		this(asList(patterns), urlPathHelper, pathMatcher, useSuffixPatternMatch, useTrailingSlashMatch, fileExtensions);
	}

	private PatternsRequestCondition(Collection<String> patterns, UrlPathHelper urlPathHelper,
			PathMatcher pathMatcher, boolean useSuffixPatternMatch, boolean useTrailingSlashMatch,
			List<String> fileExtensions) {

		this.patterns = Collections.unmodifiableSet(prependLeadingSlash(patterns));
		this.pathHelper = (urlPathHelper != null ? urlPathHelper : new UrlPathHelper());
		this.pathMatcher = (pathMatcher != null ? pathMatcher : new AntPathMatcher());
		this.useSuffixPatternMatch = useSuffixPatternMatch;
		this.useTrailingSlashMatch = useTrailingSlashMatch;
		if (fileExtensions != null) {
			for (String fileExtension : fileExtensions) {
				if (fileExtension.charAt(0) != '.') {
					fileExtension = "." + fileExtension;
				}
				this.fileExtensions.add(fileExtension);
			}
		}
	}


	private static List<String> asList(String... patterns) {
		return (patterns != null ? Arrays.asList(patterns) : Collections.<String>emptyList());
	}

	private static Set<String> prependLeadingSlash(Collection<String> patterns) {
		if (patterns == null) {
			return Collections.emptySet();
		}
		Set<String> result = new LinkedHashSet<String>(patterns.size());
		for (String pattern : patterns) {
			if (StringUtils.hasLength(pattern) && !pattern.startsWith("/")) {
				pattern = "/" + pattern;
			}
			result.add(pattern);
		}
		return result;
	}

	public Set<String> getPatterns() {
		return this.patterns;
	}

	@Override
	protected Collection<String> getContent() {
		return this.patterns;
	}

	@Override
	protected String getToStringInfix() {
		return " || ";
	}

	@Override
	public PatternsRequestCondition combine(PatternsRequestCondition other) {
		Set<String> result = new LinkedHashSet<String>();
		if (!this.patterns.isEmpty() && !other.patterns.isEmpty()) {
			for (String pattern1 : this.patterns) {
				for (String pattern2 : other.patterns) {
					result.add(this.pathMatcher.combine(pattern1, pattern2));
				}
			}
		}
		else if (!this.patterns.isEmpty()) {
			result.addAll(this.patterns);
		}
		else if (!other.patterns.isEmpty()) {
			result.addAll(other.patterns);
		}
		else {
			result.add("");
		}
		return new PatternsRequestCondition(result, this.pathHelper, this.pathMatcher, this.useSuffixPatternMatch,
				this.useTrailingSlashMatch, this.fileExtensions);
	}

	@Override
	public PatternsRequestCondition getMatchingCondition(HttpServletRequest request) {

		if (this.patterns.isEmpty()) {
			return this;
		}

		String lookupPath = this.pathHelper.getLookupPathForRequest(request);
		List<String> matches = getMatchingPatterns(lookupPath);

		return matches.isEmpty() ? null :
			new PatternsRequestCondition(matches, this.pathHelper, this.pathMatcher, this.useSuffixPatternMatch,
					this.useTrailingSlashMatch, this.fileExtensions);
	}

	public List<String> getMatchingPatterns(String lookupPath) {
		List<String> matches = new ArrayList<String>();
		for (String pattern : this.patterns) {
			String match = getMatchingPattern(pattern, lookupPath);
			if (match != null) {
				matches.add(match);
			}
		}
		Collections.sort(matches, this.pathMatcher.getPatternComparator(lookupPath));
		return matches;
	}

	private String getMatchingPattern(String pattern, String lookupPath) {
		if (pattern.equals(lookupPath)) {
			return pattern;
		}
		if (this.useSuffixPatternMatch) {
			if (!this.fileExtensions.isEmpty() && lookupPath.indexOf('.') != -1) {
				for (String extension : this.fileExtensions) {
					if (this.pathMatcher.match(pattern + extension, lookupPath)) {
						return pattern + extension;
					}
				}
			}
			else {
				boolean hasSuffix = pattern.indexOf('.') != -1;
				if (!hasSuffix && this.pathMatcher.match(pattern + ".*", lookupPath)) {
					return pattern + ".*";
				}
			}
		}
		if (this.pathMatcher.match(pattern, lookupPath)) {
			return pattern;
		}
		if (this.useTrailingSlashMatch) {
			if (!pattern.endsWith("/") && this.pathMatcher.match(pattern + "/", lookupPath)) {
				return pattern +"/";
			}
		}
		return null;
	}

	@Override
	public int compareTo(PatternsRequestCondition other, HttpServletRequest request) {
		String lookupPath = this.pathHelper.getLookupPathForRequest(request);
		Comparator<String> patternComparator = this.pathMatcher.getPatternComparator(lookupPath);
		Iterator<String> iterator = this.patterns.iterator();
		Iterator<String> iteratorOther = other.patterns.iterator();
		while (iterator.hasNext() && iteratorOther.hasNext()) {
			int result = patternComparator.compare(iterator.next(), iteratorOther.next());
			if (result != 0) {
				return result;
			}
		}
		if (iterator.hasNext()) {
			return -1;
		}
		else if (iteratorOther.hasNext()) {
			return 1;
		}
		else {
			return 0;
		}
	}

}