如何在SpEL中使用自定义密钥测试Spring @Cacheable

import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.expression.Expression;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;

public class CustomCacheKeyGenerator implements KeyGenerator {
    
    private ExpressionParser parser = new SpelExpressionParser();
    private Expression expression;
    
    public CustomCacheKeyGenerator(String spelExpression) {
        this.expression = parser.parseExpression(spelExpression);
    }
    
    @Override
    public Object generate(Object target, Method method, Object... params) {
        StandardEvaluationContext context = new StandardEvaluationContext();
        context.setVariable("params", params);
        return expression.getValue(context);
    }
}

@Cacheable(value = "myCache", keyGenerator = "customCacheKeyGenerator")
public Object myMethod(String param) {
    // 方法逻辑
}