前端修复，日志功能加入

src/main/java/com/mzh/library/util/JdbcUtil.java

@@ -8,10 +8,17 @@ import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.util.Properties;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 public final class JdbcUtil {
+    private static final Logger LOGGER = Logger.getLogger(JdbcUtil.class.getName());
     private static final String CONFIG_FILE = "db.properties";
     private static final String DEFAULT_DRIVER = "com.mysql.cj.jdbc.Driver";
+    private static final String DRIVER_KEY = "db.driver";
+    private static final String URL_KEY = "db.url";
+    private static final String USERNAME_KEY = "db.username";
+    private static final String PASSWORD_KEY = "db.password";
 
     @FunctionalInterface
     public interface TransactionCallback<T> {
@@ -23,16 +30,42 @@ public final class JdbcUtil {
 
     public static Connection getConnection() {
         Properties properties = loadProperties();
-        String driver = properties.getProperty("db.driver", DEFAULT_DRIVER);
-        String url = required(properties, "db.url");
-        String username = required(properties, "db.username");
-        String password = required(properties, "db.password");
+        String driver = properties.getProperty(DRIVER_KEY, DEFAULT_DRIVER);
+        String url = required(properties, URL_KEY);
+        String username = required(properties, USERNAME_KEY);
+        String password = required(properties, PASSWORD_KEY);
+
+        LOGGER.info("Database connection configuration resolved"
+            + " file=" + CONFIG_FILE
+            + " driverKey=" + DRIVER_KEY
+            + " driver=" + safeLogValue(driver)
+            + " jdbcUrl=" + redactJdbcUrl(url)
+            + " usernameKey=" + USERNAME_KEY
+            + " usernameConfigured=" + !username.isEmpty()
+            + " password=<redacted>");
+        LOGGER.info("Database connection attempt"
+            + " driverKey=" + DRIVER_KEY
+            + " driver=" + safeLogValue(driver)
+            + " jdbcUrl=" + redactJdbcUrl(url)
+            + " usernameKey=" + USERNAME_KEY);
 
         try {
             Class.forName(driver);
-            return DriverManager.getConnection(url, username, password);
-        } catch (ClassNotFoundException | SQLException ex) {
+            Connection connection = DriverManager.getConnection(url, username, password);
+            LOGGER.info("Database connection established jdbcUrl=" + redactJdbcUrl(url)
+                + " usernameKey=" + USERNAME_KEY);
+            return connection;
+        } catch (ClassNotFoundException ex) {
+            LOGGER.log(Level.SEVERE, "JDBC driver unavailable driver=" + safeLogValue(driver)
+                + " jdbcUrl=" + redactJdbcUrl(url)
+                + " usernameKey=" + USERNAME_KEY, ex);
             throw new DaoException("Unable to open database connection", ex);
+        } catch (SQLException ex) {
+            SQLException safeException = safeSqlException(ex);
+            LOGGER.log(Level.SEVERE, "Database connection failed driver=" + safeLogValue(driver)
+                + " jdbcUrl=" + redactJdbcUrl(url)
+                + " usernameKey=" + USERNAME_KEY, safeException);
+            throw new DaoException("Unable to open database connection", safeException);
         }
     }
 
@@ -68,13 +101,20 @@ public final class JdbcUtil {
             .getContextClassLoader()
             .getResourceAsStream(CONFIG_FILE)) {
             if (inputStream == null) {
+                LOGGER.severe("Database configuration file not found file=" + CONFIG_FILE);
                 throw new DaoException("Missing database configuration file: " + CONFIG_FILE, null);
             }
 
             Properties properties = new Properties();
             properties.load(inputStream);
+            LOGGER.info("Database configuration loaded file=" + CONFIG_FILE
+                + " driverConfigured=" + hasText(properties, DRIVER_KEY)
+                + " urlConfigured=" + hasText(properties, URL_KEY)
+                + " usernameConfigured=" + hasText(properties, USERNAME_KEY)
+                + " passwordConfigured=" + hasText(properties, PASSWORD_KEY));
             return properties;
         } catch (IOException ex) {
+            LOGGER.log(Level.SEVERE, "Unable to read database configuration file=" + CONFIG_FILE, ex);
             throw new DaoException("Unable to read database configuration", ex);
         }
     }
@@ -82,8 +122,55 @@ public final class JdbcUtil {
     private static String required(Properties properties, String key) {
         String value = properties.getProperty(key);
         if (value == null || value.trim().isEmpty()) {
+            LOGGER.severe("Missing database configuration value key=" + key);
             throw new DaoException("Missing database configuration value: " + key, null);
         }
         return value.trim();
     }
+
+    private static String redactJdbcUrl(String value) {
+        if (value == null) {
+            return "";
+        }
+        return safeLogValue(redactSensitive(value));
+    }
+
+    private static SQLException safeSqlException(SQLException ex) {
+        SQLException safeException = new SQLException(
+            safeLogValue(redactSensitive(ex.getMessage())),
+            ex.getSQLState(),
+            ex.getErrorCode()
+        );
+        safeException.setStackTrace(ex.getStackTrace());
+        return safeException;
+    }
+
+    private static String redactSensitive(String value) {
+        if (value == null) {
+            return "";
+        }
+        return value.replaceAll("(?i)(password|pwd|pass|secret|token)(\\s*[=:]\\s*)([^;&\\s]*)", "$1$2<redacted>");
+    }
+
+    private static boolean hasText(Properties properties, String key) {
+        String value = properties.getProperty(key);
+        return value != null && !value.trim().isEmpty();
+    }
+
+    private static String safeLogValue(String value) {
+        if (value == null) {
+            return "";
+        }
+
+        StringBuilder builder = new StringBuilder();
+        int limit = Math.min(value.length(), 240);
+        for (int i = 0; i < limit; i++) {
+            char current = value.charAt(i);
+            builder.append(Character.isISOControl(current) ? '?' : current);
+        }
+        if (value.length() > limit) {
+            builder.append("...");
+        }
+        return builder.toString();
+    }
 }