MyBatis 加载 XML：java.io.IOException：找不到资源（eclipse）

MyBatis loading XML : java.io.IOException: Could not find resource (eclipse)

提问by libik

I found strange behaviour while using MyBatis with Eclipse.

我在 Eclipse 中使用 MyBatis 时发现了奇怪的行为。

I have difficulty with MyBatis with finding my xml, so I tried to use absolute path (just for testing purposes) and it still throw error :

MyBatis 很难找到我的 xml，所以我尝试使用绝对路径（仅用于测试目的），但它仍然抛出错误：

To be sure that file exists, I added check for file existence before using it as Resource, so I am sure that this file exists :

为了确保该文件存在，我在将其用作资源之前添加了文件存在检查，因此我确定该文件存在：

        String resource = "e:/prace/workspace/SpringBatis/src/main/java/com/mkyong/MyBatis/xml/batisConfig.xml";// path of the mybatis configuration file.
        File file = new File(resource);
        System.out.println(file.exists());
        Reader reader = Resources.getResourceAsReader(resource);// read the mybatis confiuguration xml file 

Having this output :

有这个输出：

true
java.io.IOException: Could not find resource e:/prace/workspace/SpringBatis/src/main/java/com/mkyong/MyBatis/xml/batisConfig.xml
    at org.apache.ibatis.io.Resources.getResourceAsStream(Resources.java:89)

Any ideas?

有任何想法吗？

采纳答案by Karthik Prasad

You have 2 scenarios

你有 2 个场景

1. Reading the file using java io. Since You had given absolute path. It will always read the file if it exists.

       String resource = "e:/prace/workspace/SpringBatis/src/main/java/com/mkyong/MyBatis/xml/batisConfig.xml";// path of the mybatis configuration file.
       File file = new File(resource);
       System.out.println(file.exists());
       Reader reader = new FileReader(resource);
   

2. The scenario where you are trying to read config file is using Resources (which is your primary goal I believe). Resources class always tries to read file from class path. Here is java comment from the Resources.java class as a proof.

   /*
     * Gets a URL as a Reader
     *
     *  @param urlString - the URL to get
     * @return A Reader with the data from the URL
     * @throws java.io.IOException If the resource cannot be found or read
   */
   public static Reader getUrlAsReader(String urlString) throws IOException {}
   

1. 使用 java io 读取文件。因为你给出了绝对路径。如果文件存在，它将始终读取文件。

       String resource = "e:/prace/workspace/SpringBatis/src/main/java/com/mkyong/MyBatis/xml/batisConfig.xml";// path of the mybatis configuration file.
       File file = new File(resource);
       System.out.println(file.exists());
       Reader reader = new FileReader(resource);
   

2. 您尝试读取配置文件的场景是使用资源（我相信这是您的主要目标）。资源类总是尝试从类路径读取文件。这是来自 Resources.java 类的 java 注释作为证明。

   /*
     * Gets a URL as a Reader
     *
     *  @param urlString - the URL to get
     * @return A Reader with the data from the URL
     * @throws java.io.IOException If the resource cannot be found or read
   */
   public static Reader getUrlAsReader(String urlString) throws IOException {}
   

Now how to resolve thisFrom the folder structure I assume you are using the Maven. Hence by default your classpath would be SpringBatis/src/main/javaor SpringBatis/src/main/resourcesHence you can provide the resource path as com/mkyong/MyBatis/xml/batisConfig.xml, in your case currently Resources path turns out be e:/prace/workspace/SpringBatis/src/main/java/e:/prace/workspace/SpringBatis/src/main/java/com/mkyong/MyBatis/xml/batisConfig.xml

现在如何解决这个问题从文件夹结构我假设您正在使用 Maven。因此，默认情况下，您的类路径将是SpringBatis/src/main/java或SpringBatis/src/main/resources因此您可以将资源路径提供为com/mkyong/MyBatis/xml/batisConfig.xml，在您的情况下，当前资源路径是e:/prace/workspace/SpringBatis/src/main/java/e:/prace/workspace/SpringBatis/src/main/java/com/mkyong/MyBatis/xml/batisConfig.xml

Thus your code would should look like.

因此你的代码应该看起来像。

 String resource = "com/mkyong/MyBatis/xml/batisConfig.xml";// path of the mybatis configuration file.
               // File file = new File(resource);
                System.out.println(file.exists());
               // Reader reader = new FileReader(resource);

If you are using eclipse you can verify the classpath as follows. Right on project->project properties-> java build path -> sources tab. You should find all th relevant classpaths. For example for your project SpringBatis you would find SpringBatis/main/java with included files, excluded files, out directory etc.

如果您使用的是 eclipse，您可以按如下方式验证类路径。就在项目-> 项目属性-> java 构建路径-> 源选项卡上。您应该找到所有相关的类路径。例如，对于您的项目 SpringBatis，您会发现 SpringBatis/main/java 包含包含文件、排除文件、输出目录等。

NoteSince you have placed batisConfig.xml under src/main/java. By default maven configures to include only */*.javafile( only java files) if need to include all the files you need to configure accordingly. But I would recommend to move the xml file to src/main/resources directory( which is again a classpath)

注意由于您已将 batisConfig.xml 放在 src/main/java 下。默认情况下，maven 配置为仅包含*/*.java文件（仅 java 文件），如果需要包含您需要相应配置的所有文件。但我建议将 xml 文件移动到 src/main/resources 目录（这又是一个类路径）