當我用想法運行tomcat時，我無法讀取.properties

我正在學習JavaWeb并在idea中部署本地tomcat9。當我嘗試通過讀取屬性檔案連接到資料庫時發生例外。應該是我的屬性檔案沒有找到。

我試圖更改檔案路徑，但沒有奏效。我該怎么辦？

這是我連接資料庫和訊息的方法

public class JDBCUtil {
    private static DataSource druidSource;
    static {
        Properties props = new Properties();
        InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("production/begin/druid.properties");
        try {
            props.load(is);
            druidSource = DruidDataSourceFactory.createDataSource(props);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static Connection getConnection() throws SQLException {
        return druidSource.getConnection();
    }
}

java.lang.NullPointerException: inStream parameter is null
    at java.base/java.util.Objects.requireNonNull(Objects.java:233)
    at java.base/java.util.Properties.load(Properties.java:407)
    at DAO.util.JDBCUtil.<clinit>(JDBCUtil.java:24)
    at servlets.AddServlet.doPost(AddServlet.java:39)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:681)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:764)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:687)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:890)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1743)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
    at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:831)

這是我的目錄

運行環境：MacOS12、idea2021.3.3、tomcat9.0.62、Java16.0.1

uj5u.com熱心網友回復：

此問題已解決。感謝 rehnoj的幫助。

ClassLoader.getSystemClassLoader().getResource() 在 servlet 容器和測驗環境中的不同行為中的答案。

正確的代碼

public class JDBCUtil {
    private static DataSource druidSource;
    static {
        Properties props = new Properties();
        InputStream is = JDBCUtil.class.getClassLoader().getResourceAsStream("druid.properties");
        try {
            props.load(is);
            druidSource = DruidDataSourceFactory.createDataSource(props);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static Connection getConnection() throws SQLException {
        return druidSource.getConnection();
    }
}

標籤：爪哇 雄猫 智能理念 java-web-启动

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