测试代码

package cn.edu.hdu.pichen.springexample;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.LinkedList;
import java.util.List;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.util.StringUtils;

import cn.edu.hdu.pichen.springexample.beans.User;

/**
 * Hello world!
 *
 */
public class App
{
    public static void main(String[] args) throws IOException
    {
        // ClassPathResource resource = new
        // ClassPathResource("./../classes/beans.xml");
        // System.out.println(resource.getPath());
        // System.out.println(resource.getDescription());
        // System.out.println(resource.getURL().getPath());
        //
        // InputStream is = resource.getInputStream();
        // BufferedReader br = new BufferedReader(new InputStreamReader(is));
        // String str = br.readLine();
        // while (str != null)
        // {
        // System.out.println(str);
        // str = br.readLine();
        // }
        //
        System.out.println(StringUtils.cleanPath(".\\beans.xml")); // \\替换为/
        System.out.println(StringUtils.cleanPath("file:core/../core/./io/Resource.class"));

        // System.out.println(StringUtils.cleanPath("./../../beans.xml"));
        // System.out.println(StringUtils.cleanPath("./tmp/tmp2/../beans.xml"));
        //
        //
        // BeanFactory factory = new XmlBeanFactory(resource);
        // User user = factory.getBean("user", User.class);
        // System.out.println("Name:" + user.getName() + "\nAge:" +
        // user.getAge());
    }
}

pom

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>cn.edu.hdu.pichen</groupId>
    <artifactId>springexample</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springexample</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>3.0.7.RELEASE</version>
        </dependency>

    </dependencies>
</project>

涉及的相关类源码

org.springframework.util.StringUtils工具类的collectionToDelimitedString方法

/**
     * Convenience method to return a Collection as a delimited (e.g. CSV)
     * String. E.g. useful for <code>toString()</code> implementations.
     * @param coll the Collection to display
     * @param delim the delimiter to use (probably a ",")
     * @param prefix the String to start each element with
     * @param suffix the String to end each element with
     * @return the delimited String
     */
    public static String collectionToDelimitedString(Collection<?> coll, String delim, String prefix, String suffix) {
        if (CollectionUtils.isEmpty(coll)) {
            return "";
        }
        StringBuilder sb = new StringBuilder();//局部变量，不需要同步，使用StringBuilder即可
        Iterator<?> it = coll.iterator();
        while (it.hasNext()) {
            sb.append(prefix).append(it.next()).append(suffix);
            if (it.hasNext()) {
                sb.append(delim);
            }
        }
        return sb.toString();
    }

该方法代码很简单，不需要多说明，就是简单的字符串拼接，依次遍历入参coll集合，并取出元素进行前缀、后缀、分隔符拼接。

入参及返回值说明

     * @param 需要处理的元素集合（如果是对象，拼接的是toString方法的字符串）
     * @param 分隔符（如分号；）
     * @param 拼接的元素前缀
     * @param 拼接的元素后缀
     * @return 处理完后的结果

举个例子：

        List<String> pathElements = new LinkedList<String>();
        pathElements.add("AAA");
        pathElements.add("BBB");
        pathElements.add("CCC");
        System.out.println(StringUtils.collectionToDelimitedString(pathElements, ";", "#", "$"));

结果打印（分隔符";"，前缀"#", 后缀"$"）：

#AAA$;#BBB$;#CCC$

org.springframework.util.StringUtils工具类的cleanPath方法

/**
     * Normalize the path by suppressing sequences like "path/.." and
     * inner simple dots.
     * <p>The result is convenient for path comparison. For other uses,
     * notice that Windows separators ("\") are replaced by simple slashes.
     * @param path the original path
     * @return the normalized path
     */
    public static String cleanPath(String path) {
        if (path == null) {
            return null;
        }
        String pathToUse = replace(path, WINDOWS_FOLDER_SEPARATOR, FOLDER_SEPARATOR);

        // Strip prefix from path to analyze, to not treat it as part of the
        // first path element. This is necessary to correctly parse paths like
        // "file:core/../core/io/Resource.class", where the ".." should just
        // strip the first "core" directory while keeping the "file:" prefix.
        int prefixIndex = pathToUse.indexOf(":");
        String prefix = "";
        if (prefixIndex != -1) {
            prefix = pathToUse.substring(0, prefixIndex + 1);
            pathToUse = pathToUse.substring(prefixIndex + 1);
        }
        if (pathToUse.startsWith(FOLDER_SEPARATOR)) {
            prefix = prefix + FOLDER_SEPARATOR;
            pathToUse = pathToUse.substring(1);
        }

        String[] pathArray = delimitedListToStringArray(pathToUse, FOLDER_SEPARATOR);
        List<String> pathElements = new LinkedList<String>();
        int tops = 0;

        for (int i = pathArray.length - 1; i >= 0; i--) {
            String element = pathArray[i];
            if (CURRENT_PATH.equals(element)) {
                // Points to current directory - drop it.
            }
            else if (TOP_PATH.equals(element)) {
                // Registering top path found.
                tops++;
            }
            else {
                if (tops > 0) {
                    // Merging path element with element corresponding to top path.
                    tops--;
                }
                else {
                    // Normal path element found.
                    pathElements.add(0, element);
                }
            }
        }

        // Remaining top paths need to be retained.
        for (int i = 0; i < tops; i++) {
            pathElements.add(0, TOP_PATH);
        }

        return prefix + collectionToDelimitedString(pathElements, FOLDER_SEPARATOR);
    }

该方法根据输入的原始路径转换成一个规格化的路径，如下示例：

.\\beans.xml -----》beans.xml

file:core/../core/./io/Resource.class -----》file:core/io/Resource.class

代码也不复杂简单说明下吧：

原文地址：https://www.cnblogs.com/chenpi/p/6421991.html