What causes "解析默认参数失败: {}" in alibaba/spring-ai-alibaba?

Fix defaultParameters in the model config to be a valid JSON object, e.g. {"temperature":0.7}

解析默认参数失败

Error message

解析默认参数失败: {}

What it means

ChatClientFactoryDelegate.mergeParameters parses the model config's defaultParameters JSON string into a Map and merges it under the caller-supplied user parameters. If the JSON cannot be parsed into Map.class, it warns with the raw string and continues with only the user parameters.

Solutions

Fix defaultParameters in the model config to be a valid JSON object, e.g. {"temperature":0.7}
Validate the JSON in the UI/API before saving model configs
Make mergeParameters throw or return an error for invalid JSON instead of silently ignoring defaults, so bad configs surface immediately

Example fix

// before
defaultParameters: "{'temperature':0.7}"
// after
defaultParameters: "{\"temperature\":0.7}"

Defensive patterns

Strategy: validation

Validate before calling

boolean isValidJsonObject(String s) {
    if (s == null || s.isBlank()) return true; // optional field
    try { new ObjectMapper().readValue(s, Map.class); return true; } catch (Exception e) { return false; }
}
// reject model configs whose defaultParameters fails isValidJsonObject

Try / catch

try { client = delegate.createChatClient(config); }
catch (Exception e) { log.warn("falling back to params without defaults: {}", e.getMessage()); }

Prevention

Use a JSON editor with validation in the admin UI for defaultParameters
Always save default params as JSON objects, never arrays or quoted strings
Round-trip test: parse what you save before persisting

When it happens

Trigger: mergedParameters -> mergeParameters with config.getDefaultParameters() that is malformed JSON, a JSON array/string/scalar instead of an object, or null-garbage from a prior save.

Common situations: Admin UI saving default params with single quotes or trailing commas; another client writing a JSON array; encoding corruption; hand-edited database rows.

Understand the failure class

Background: JSON parse error: "Unexpected token" / "not valid JSON" / "failed to parse" — what JSON parsers are really complaining about — this error's family across 45 libraries.

Related errors

AI-assisted analysis of alibaba/spring-ai-alibaba@f82da0b50f (2026-09-09). Data as JSON: /api/errors/f5d603e4a2289401. Report an issue: GitHub.

Appendix: source

Thrown at spring-ai-alibaba-admin/spring-ai-alibaba-admin-server-start/src/main/java/com/alibaba/cloud/ai/studio/admin/service/client/ChatClientFactoryDelegate.java:140

     *
     * @param userParameters 用户传入的参数
     * @return 合并后的参数
     */
    private Map<String, Object> mergeParameters(ModelConfigDO config, Map<String, Object> userParameters) {
        Map<String, Object> mergedParameters = new HashMap<>();
        
        // 首先添加默认参数
        if (StringUtils.hasText(config.getDefaultParameters())) {
            try {
                @SuppressWarnings("unchecked")
                Map<String, Object> defaultParams = objectMapper.readValue(
                        config.getDefaultParameters(),
                        Map.class
                );
                mergedParameters.putAll(defaultParams);
                log.debug("加载默认参数: {}", defaultParams);
            } catch (Exception e) {
                log.warn("解析默认参数失败: {}", config.getDefaultParameters(), e);
            }
        }
        
        // 然后添加用户参数（覆盖默认参数）
        if (userParameters != null) {
            mergedParameters.putAll(userParameters);
            log.debug("用户参数: {}", userParameters);
        }
        
        log.debug("合并后的参数: {}", mergedParameters);
        return mergedParameters;
    }
}

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