alibaba/druid · error · IllegalArgumentException

Config DataSource error.

Error message

Config DataSource error.

What it means

Thrown when DruidDataSourceFactory.config(dataSource, configFileProperties) raises a SQLException while applying the properties loaded from the remote/file config to the DruidDataSource. The config step sets url, username, driver, pool sizing, etc.; a SQLException here means one of those properties was rejected (invalid value, parse failure, or a setter throwing). It is wrapped as IllegalArgumentException to fail datasource init fast.

Source

Thrown at core/src/main/java/com/alibaba/druid/filter/config/ConfigFilter.java:134

        // 判断是否需要解密，如果需要就进行解密行动
        boolean decrypt = isDecrypt(connectionProperties, configFileProperties);

        if (configFileProperties == null) {
            if (decrypt) {
                decrypt(dataSource, null);
            }
            return;
        }

        if (decrypt) {
            decrypt(dataSource, configFileProperties);
        }

        try {
            DruidDataSourceFactory.config(dataSource, configFileProperties);
        } catch (SQLException e) {
            throw new IllegalArgumentException("Config DataSource error.", e);
        }
    }

    public boolean isDecrypt(Properties connectionProperties, Properties configFileProperties) {
        String decrypterId = connectionProperties.getProperty(CONFIG_DECRYPT);
        if (decrypterId == null || decrypterId.length() == 0) {
            if (configFileProperties != null) {
                decrypterId = configFileProperties.getProperty(CONFIG_DECRYPT);
            }
        }

        if (decrypterId == null || decrypterId.length() == 0) {
            decrypterId = System.getProperty(SYS_PROP_CONFIG_DECRYPT);
        }

        return Boolean.valueOf(decrypterId);
    }

View on GitHub (pinned to fa8dc99126)

Solutions

1. Read IllegalArgumentException.getCause() (the SQLException) - its message names the offending property.
2. Validate every key in the config file against DruidDataSourceFactory's accepted property names.
3. Correct or remove the offending property and reload.

// Pre-validate the config file's property values before init:
Properties p = loadConfig(configFilePath);
for (String key : p.stringPropertyNames()) {
    String val = p.getProperty(key);
    // e.g. numeric checks for maxActive, initialSize, etc.
    if (key.endsWith("Active") || key.endsWith("Size")) Integer.parseInt(val);
}

try {
    ds.setFilters("config"); ds.init();
} catch (IllegalArgumentException e) {
    if (e.getMessage().equals("Config DataSource error.") && e.getCause() instanceof SQLException) {
        // the cause names the offending property; fix config file and reload
    }
    throw e;
}

When it happens

Trigger: A valid config file was loaded (loadPropertyFromConfigFile returned non-null) but one of the applied properties is malformed - e.g. an unparseable numeric pool-sizing property, an invalid driver class, or a setter validation that throws SQLException.

Common situations: config.file points at a properties file with a typo (e.g. maxActive=abc), a deprecated/renamed property key, or a value that violates a setter invariant (see errors 12, 13, 14, 16).

Related errors

• ConfigLoader only support DruidDataSource
• Cannot load remote config file from the [config.file={config
• Failed to decrypt.
• {className}
• maxEvictableIdleTimeMillis must be grater than minEvictableI

AI-assisted analysis of alibaba/druid@fa8dc99126 (2026-08-14). Data as JSON: /api/errors/592e32db2d2cd618. Report an issue: GitHub.