如果没有依赖spring,可以将分割线下的方法去掉
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.util.ResourceUtils;
import java.io.*;
import java.net.URL;
import java.net.URLConnection;
import java.nio.charset.Charset;
import java.util.Properties;
public class Resources {
private static ClassLoaderWrapper classLoaderWrapper = new ClassLoaderWrapper();
private static Charset charset;
Resources() {
}
public static ClassLoader getDefaultClassLoader() {
return classLoaderWrapper.defaultClassLoader;
}
public static void setDefaultClassLoader(ClassLoader defaultClassLoader) {
classLoaderWrapper.defaultClassLoader = defaultClassLoader;
}
public static URL getResourceURL(String resource) throws IOException {
return getResourceURL((ClassLoader)null, resource);
}
public static URL getResourceURL(ClassLoader loader, String resource) throws IOException {
URL url = classLoaderWrapper.getResourceAsURL(resource, loader);
if(url == null) {
throw new IOException("Could not find resource " + resource);
} else {
return url;
}
}
public static InputStream getResourceAsStream(String resource) throws IOException {
return getResourceAsStream((ClassLoader)null, resource);
}
public static InputStream getResourceAsStream(Class<?> clazz, String resource) throws IOException {
InputStream in = classLoaderWrapper.getResourceAsStream(resource, clazz);
if(in == null) {
throw new IOException("Could not find resource " + resource);
} else {
return in;
}
}
public static InputStream getResourceAsStream(ClassLoader loader, String resource) throws IOException {
InputStream in = classLoaderWrapper.getResourceAsStream(resource, loader);
if(in == null) {
throw new IOException("Could not find resource " + resource);
} else {
return in;
}
}
public static Properties getResourceAsProperties(String resource) throws IOException {
Properties props = new Properties();
InputStream in = getResourceAsStream(resource);
props.load(in);
in.close();
return props;
}
public static Properties getResourceAsProperties(ClassLoader loader, String resource) throws IOException {
Properties props = new Properties();
InputStream in = getResourceAsStream(loader, resource);
props.load(in);
in.close();
return props;
}
public static Reader getResourceAsReader(String resource) throws IOException {
InputStreamReader reader;
if(charset == null) {
reader = new InputStreamReader(getResourceAsStream(resource));
} else {
reader = new InputStreamReader(getResourceAsStream(resource), charset);
}
return reader;
}
public static Reader getResourceAsReader(ClassLoader loader, String resource) throws IOException {
InputStreamReader reader;
if(charset == null) {
reader = new InputStreamReader(getResourceAsStream(loader, resource));
} else {
reader = new InputStreamReader(getResourceAsStream(loader, resource), charset);
}
return reader;
}
public static File getResourceAsFile(String resource) throws IOException {
return new File(getResourceURL(resource).getFile());
}
public static File getResourceAsFile(ClassLoader loader, String resource) throws IOException {
return new File(getResourceURL(loader, resource).getFile());
}
public static InputStream getUrlAsStream(String urlString) throws IOException {
URL url = new URL(urlString);
URLConnection conn = url.openConnection();
return conn.getInputStream();
}
public static Reader getUrlAsReader(String urlString) throws IOException {
InputStreamReader reader;
if(charset == null) {
reader = new InputStreamReader(getUrlAsStream(urlString));
} else {
reader = new InputStreamReader(getUrlAsStream(urlString), charset);
}
return reader;
}
public static Properties getUrlAsProperties(String urlString) throws IOException {
Properties props = new Properties();
InputStream in = getUrlAsStream(urlString);
props.load(in);
in.close();
return props;
}
public static Class<?> classForName(String className) throws ClassNotFoundException {
return classLoaderWrapper.classForName(className);
}
public static Charset getCharset() {
return charset;
}
public static void setCharset(Charset charset) {
charset = charset;
}
//############################ 华丽分割线 通过 spring 工具类 #################################
public static File getFileWithResourceUtils(String resource) throws FileNotFoundException {
return ResourceUtils.getFile(resource);
}
public Resource getResourceWithPathMatchingResourcePatternResolver(String resource) {
PathMatchingResourcePatternResolver pathMatchingResourcePatternResolver = new PathMatchingResourcePatternResolver();
return pathMatchingResourcePatternResolver.getResource(resource);
}
public Resource[] getResourcesWithPathMatchingResourcePatternResolver(String resource) throws IOException {
PathMatchingResourcePatternResolver pathMatchingResourcePatternResolver = new PathMatchingResourcePatternResolver();
return pathMatchingResourcePatternResolver.getResources(resource);
}
public InputStream getInputStreamWithClassPathResource(String resource, Class<?> clazz) throws IOException {
if (clazz != null) {
return new ClassPathResource(resource, clazz).getInputStream();
} else {
return new ClassPathResource(resource).getInputStream();
}
}
}
class ClassLoaderWrapper {
ClassLoader defaultClassLoader;
ClassLoader systemClassLoader;
ClassLoaderWrapper() {
try {
this.systemClassLoader = ClassLoader.getSystemClassLoader();
} catch (SecurityException var2) {
;
}
}
public URL getResourceAsURL(String resource) {
return this.getResourceAsURL(resource, this.getClassLoaders((ClassLoader)null));
}
public URL getResourceAsURL(String resource, ClassLoader classLoader) {
return this.getResourceAsURL(resource, this.getClassLoaders(classLoader));
}
public InputStream getResourceAsStream(String resource) {
return this.getResourceAsStream(resource, this.getClassLoaders((ClassLoader)null));
}
public InputStream getResourceAsStream(String resource, ClassLoader classLoader) {
return this.getResourceAsStream(resource, this.getClassLoaders(classLoader));
}
public Class<?> classForName(String name) throws ClassNotFoundException {
return this.classForName(name, this.getClassLoaders((ClassLoader)null));
}
public Class<?> classForName(String name, ClassLoader classLoader) throws ClassNotFoundException {
return this.classForName(name, this.getClassLoaders(classLoader));
}
InputStream getResourceAsStream(String resource, ClassLoader[] classLoader) {
ClassLoader[] arr$ = classLoader;
int len$ = classLoader.length;
for(int i$ = 0; i$ < len$; ++i$) {
ClassLoader cl = arr$[i$];
if(null != cl) {
InputStream returnValue = cl.getResourceAsStream(resource);
if(null == returnValue) {
returnValue = cl.getResourceAsStream("/" + resource);
}
if(null != returnValue) {
return returnValue;
}
}
}
return null;
}
URL getResourceAsURL(String resource, ClassLoader[] classLoader) {
ClassLoader[] arr$ = classLoader;
int len$ = classLoader.length;
for(int i$ = 0; i$ < len$; ++i$) {
ClassLoader cl = arr$[i$];
if(null != cl) {
URL url = cl.getResource(resource);
if(null == url) {
url = cl.getResource("/" + resource);
}
if(null != url) {
return url;
}
}
}
return null;
}
Class<?> classForName(String name, ClassLoader[] classLoader) throws ClassNotFoundException {
ClassLoader[] arr$ = classLoader;
int len$ = classLoader.length;
for(int i$ = 0; i$ < len$; ++i$) {
ClassLoader cl = arr$[i$];
if(null != cl) {
try {
Class<?> c = Class.forName(name, true, cl);
if(null != c) {
return c;
}
} catch (ClassNotFoundException var8) {
;
}
}
}
throw new ClassNotFoundException("Cannot find class: " + name);
}
ClassLoader[] getClassLoaders(ClassLoader classLoader) {
return new ClassLoader[]{classLoader, this.defaultClassLoader, Thread.currentThread().getContextClassLoader(), this.getClass().getClassLoader(), this.systemClassLoader};
}
public InputStream getResourceAsStream(String resource, Class<?> clazz) {
return clazz.getResourceAsStream(resource);
}
}
测试方法
try {
File file = ResourceUtils.getFile("classpath:" + Resources.class.getName().replace(".", "/") + ".class");
BufferedReader br = new BufferedReader(new FileReader(file));
String str = null;
while ((str = br.readLine()) != null) {
System.out.println(str);
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
PathMatchingResourcePatternResolver p = new PathMatchingResourcePatternResolver();
BufferedReader br = new BufferedReader(new InputStreamReader(p.getResource(Resources.class.getName().replace(".", "/") + ".class").getInputStream()));
String str = null;
while ((str = br.readLine()) != null) {
System.out.println(str);
}
} catch (IOException e) {
e.printStackTrace();
}
//classpath 加不加都可以呦
try { PathMatchingResourcePatternResolver p = new PathMatchingResourcePatternResolver(); BufferedReader br = new BufferedReader(new InputStreamReader(p.getResources("classpath:"+Resources.class.getName().replace(".", "/") + ".class")[0].getInputStream())); String str = null; while ((str = br.readLine()) != null) { System.out.println(str); } } catch (IOException e) { e.printStackTrace(); } try { BufferedReader br = new BufferedReader(new InputStreamReader(Resources.getResourceAsStream(Resources.class.getName().replace(".", "/") + ".class"))); String str = null; while ((str = br.readLine()) != null) { System.out.println(str); } } catch (IOException e) { e.printStackTrace(); } try { BufferedReader br = new BufferedReader(new InputStreamReader(Resources.getResourceAsStream(Resources.class,"Resources.class"))); String str = null; while ((str = br.readLine()) != null) { System.out.println(str); } } catch (IOException e) { e.printStackTrace(); } try { BufferedReader br = new BufferedReader(new InputStreamReader(new ClassPathResource(Resources.class.getName().replace(".", "/") + ".class").getInputStream())); String str = null; while ((str = br.readLine()) != null) { System.out.println(str); } } catch (IOException e) { e.printStackTrace(); } try { BufferedReader br = new BufferedReader(new InputStreamReader(new ClassPathResource("Resources.class", Resources.class).getInputStream())); String str = null; while ((str = br.readLine()) != null) { System.out.println(str); } } catch (IOException e) { e.printStackTrace(); } try { BufferedReader br = new BufferedReader(new InputStreamReader(Resources.getResourceAsStream(Resources.class.getName().replace(".", "/") + ".class"))); String str = null; while ((str = br.readLine()) != null) { System.out.println(str); } } catch (IOException e) { e.printStackTrace(); }
可以获取到多个,包括我们自己定义的Resources.class
try {
PathMatchingResourcePatternResolver p = new PathMatchingResourcePatternResolver();
BufferedReader br = new BufferedReader(new InputStreamReader(p.getResources("classpath*:com/**/Resources.class")[0].getInputStream()));
String str = null;
while ((str = br.readLine()) != null) {
System.out.println(str);
}
} catch (IOException e) {
e.printStackTrace();
}
不可以获取到
try {
PathMatchingResourcePatternResolver p = new PathMatchingResourcePatternResolver();
BufferedReader br = new BufferedReader(new InputStreamReader(p.getResources("classpath:com/**/Resources.class")[0].getInputStream()));
String str = null;
while ((str = br.readLine()) != null) {
System.out.println(str);
}
} catch (IOException e) {
e.printStackTrace();
}
原因看一下 方法的源代码就发现了哦!
public Resource[] getResources(String locationPattern) throws IOException {
Assert.notNull(locationPattern, "Location pattern must not be null");
if(locationPattern.startsWith("classpath*:")) {
return this.getPathMatcher().isPattern(locationPattern.substring("classpath*:".length()))?this.findPathMatchingResources(locationPattern):this.findAllClassPathResources(locationPattern.substring("classpath*:".length()));
} else {
int prefixEnd = locationPattern.indexOf(":") + 1;
return this.getPathMatcher().isPattern(locationPattern.substring(prefixEnd))?this.findPathMatchingResources(locationPattern):new Resource[]{this.getResourceLoader().getResource(locationPattern)};
}
}
findPathMatchingResources方法中调用getResources 最后执行的 代码中标红色的部分,通过resourceLoader返回资源。
classpath*: 和 classpath: 不同的地方看一下getResources方法中 代码中标红色的 部分。