java 获取resources下文件的路径 使用 ClassLoader类 获取路径，使用流的方式读取

java 获取resources下文件的路径 使用 ClassLoader类，使用流的方式读取

Java获取resources下文件的路径

在Java开发中，我们经常需要读取resources目录下的文件，例如配置文件、模板文件等。本文将介绍如何获取resources下文件的路径，并提供相应的代码示例。

1. resources目录

在Java项目中，resources目录是存放资源文件的常用目录。一般情况下，resources目录位于项目的src/main目录下，结构如下：

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src
└── main
    ├── java
    └── resources
        ├── config.properties
        └── template.txt
1.
2.
3.
4.
5.
6.

在这个例子中，resources目录下有一个config.properties配置文件和一个template.txt模板文件。

2. 获取resources下文件的路径

要获取resources下文件的路径，我们可以使用Java的ClassLoader类。ClassLoader类是Java中用于加载类和资源的类加载器的基类。通过ClassLoader类，我们可以获取resources目录的绝对路径。

下面是一个获取resources下文件路径的示例代码：

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public class ResourceExample {
    public static void main(String[] args) {
        // 获取config.properties文件路径
        String configPath = ResourceExample.class.getClassLoader().getResource("config.properties").getPath();
        System.out.println("config.properties文件路径：" + configPath);

    <span class="token comment">// 获取template.txt文件路径</span>
    <span class="token class-name">String</span> templatePath <span class="token operator">=</span> <span class="token class-name">ResourceExample</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">.</span><span class="token function">getClassLoader</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getResource</span><span class="token punctuation">(</span><span class="token string">"template.txt"</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getPath</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"template.txt文件路径："</span> <span class="token operator">+</span> templatePath<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>


    <span class="token comment">// 获取template.txt文件路径</span>
    <span class="token class-name">String</span> templatePath <span class="token operator">=</span> <span class="token class-name">ResourceExample</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">.</span><span class="token function">getClassLoader</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getResource</span><span class="token punctuation">(</span><span class="token string">"template.txt"</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getPath</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"template.txt文件路径："</span> <span class="token operator">+</span> templatePath<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
}

在上面的示例中，我们使用ClassLoader的getResource()方法获取配置文件和模板文件的路径。getResource()方法需要传入相对于resources目录的文件路径，返回一个URL对象。通过URL对象的getPath()方法，就可以获取文件的绝对路径。

需要注意的是，getPath()方法返回的是URL编码过的路径，如果路径中包含特殊字符，需要进行解码。

3. 代码示例运行结果

运行上述代码示例，会输出配置文件和模板文件的绝对路径。假设项目的根目录为/path/to/project，则输出结果如下：

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config.properties文件路径：/path/to/project/target/classes/config.properties
template.txt文件路径：/path/to/project/target/classes/template.txt
1.
2.

这里的/path/to/project是根据具体项目的绝对路径而定。

4. 使用文件流读取resources下的文件

获取到文件的绝对路径之后，我们可以使用文件流来读取文件内容。下面是一个使用文件流读取文件的示例代码：

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public class ResourceExample {
    public static void main(String[] args) {
        try {
            // 获取config.properties文件路径
            String configPath = ResourceExample.class.getClassLoader().getResource("config.properties").getPath();
            FileInputStream configFileInputStream = new FileInputStream(configPath);
            // 读取文件内容...

        <span class="token comment">// 获取template.txt文件路径</span>
        <span class="token class-name">String</span> templatePath <span class="token operator">=</span> <span class="token class-name">ResourceExample</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">.</span><span class="token function">getClassLoader</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getResource</span><span class="token punctuation">(</span><span class="token string">"template.txt"</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getPath</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">FileInputStream</span> templateFileInputStream <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FileInputStream</span><span class="token punctuation">(</span>templatePath<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token comment">// 读取文件内容...</span>

        <span class="token comment">// 关闭文件流</span>
        configFileInputStream<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        templateFileInputStream<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">IOException</span> e<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        e<span class="token punctuation">.</span><span class="token function">printStackTrace</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>


        <span class="token comment">// 获取template.txt文件路径</span>
        <span class="token class-name">String</span> templatePath <span class="token operator">=</span> <span class="token class-name">ResourceExample</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">.</span><span class="token function">getClassLoader</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getResource</span><span class="token punctuation">(</span><span class="token string">"template.txt"</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">getPath</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">FileInputStream</span> templateFileInputStream <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FileInputStream</span><span class="token punctuation">(</span>templatePath<span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token comment">// 读取文件内容...</span>

        <span class="token comment">// 关闭文件流</span>
        configFileInputStream<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        templateFileInputStream<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span> <span class="token keyword">catch</span> <span class="token punctuation">(</span><span class="token class-name">IOException</span> e<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        e<span class="token punctuation">.</span><span class="token function">printStackTrace</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>
<span class="token punctuation">}</span>
}

在上面的示例中，我们通过FileInputStream类创建了两个文件输入流，分别读取了配置文件和模板文件的内容。读取文件内容的部分可以根据实际需求进行扩展。

需要注意的是，使用文件流读取文件时，需要注意文件流的关闭操作。可以使用try-catch-finally代码块来确保文件流的关闭，以免造成资源泄漏。

5. 总结

本文介绍了如何使用Java获取resources下文件的路径，并提供了相应的代码示例。通过使用ClassLoader类，我们可以方便地获取resources目录下文件的绝对路径，并通过文件流读取文件内容。希望本文对你在Java开发中读取resources目录下文件有所帮助。

参考资料

• [Java API Documentation](

旅程

journey
    title 获取resources下文件的路径
    section 准备工作
    获取resources目录结构
    获取resources目录下文件的路径
    使用文件流读取文件内容
    总结

关系图

erDiagram
    class ResourceExample {
        String configPath

原文链接：https://blog.51cto.com/u_16175466/7186650