我需要将 POJO 对象转换为其相应的 protobuf 消息。我正在编写一个实用程序，它将使用反射并生成 protobuf 消息。

我有以下 POJO 模型 -

public class Person {
   int id;
   Map<String,String> properties;
   String name;
   Address address;
   Gender gender;
}

public class Address {
   private String line1;
   private String line2;
   private String line3;
   private String City;
   private String state;
}

public enum Gender {
   MALE,FEMALE
}

相应的原型消息 -

message PersonMsg {
  int32 id = 1;
  map<string, string> properties = 2;
  string name = 3;
  AddressMsg address = 4;
  Gender gender = 5;
}

message AddressMsg {
  string line1 = 1;
  string line2 = 2;
  string line3 = 3;
  string city = 4;
  string state = 5;
  string country = 6;
  string pincode = 7;

}

enum Gender{
  Gender_DEFAULT = 0;
  Gender_MALE = 1;
  Gender_FEMALE = 2;
}

转换器逻辑类似于 - 对于标量/基元类型动态调用 gette/setter 并在 protobuf 生成器中填充数据。如果字段是自定义类型（在本例中为地址字段），则递归调用该方法并填充字段 -

private static GeneratedMessageV3 getMessage(Object o) throws ClassNotFoundException
    String protoName = o.getClass().getName()+"Proto";
    Class outerClass = Class.forName(protoName);
    String msgName = protoName+"$"+ o.getClass().getSimpleName()+"Msg";
    Class modelClass = o.getClass();
    Class protoMsg = Class.forName(msgName);

    try {
        Method method = protoMsg.getMethod("newBuilder", null);
        com.google.protobuf.GeneratedMessageV3.Builder builder =  (com.google.protobuf.GeneratedMessageV3.Builder)method.invoke(null, null);

        Field[] fields = o.getClass().getDeclaredFields();
        for(Field field : fields){
            if(field.getType().isPrimitive() || field.getType().isAssignableFrom(String.class)){
                Method getMethod = modelClass.getMethod("get"+ CaseFormat.LOWER_CAMEL.to(CaseFormat.UPPER_CAMEL, field.getName()));
                Object value = getMethod.invoke(o, null);
                Method setMethod = findSetterMethod(builder.getClass(), field);
                setMethod.invoke(builder, value);
            } else if(field.getType().isEnum()){
                Method getMethod = modelClass.getMethod("get"+ CaseFormat.LOWER_CAMEL.to(CaseFormat.UPPER_CAMEL, field.getName()));
                Enum modelEnumValue = (Enum) getMethod.invoke(o, null);
                String protoEnumClassName = field.getType().getName()+"Proto$"+field.getType().getSimpleName();
                Class protoEnumClass = Class.forName(protoEnumClassName);
                Method enumMethod = protoEnumClass.getDeclaredMethod("values", null);
                Enum[] protoValues = (Enum[]) enumMethod.invoke(null, null);
                Enum protoValue = null;
                for(Enum value : protoValues){
                    if(value.name().replace(field.getType().getSimpleName()+"_", "").equals(modelEnumValue.name())){
                        protoValue = value;
                    }
                }
                if(protoValue!=null) {
                    Method setMethod = findSetterMethod(builder.getClass(), field);
                    setMethod.invoke(builder, protoValue);
                }
            } else if(Collection.class.isAssignableFrom(field.getType()) || Map.class.isAssignableFrom(field.getType())){
                if(Map.class.isAssignableFrom(field.getType())){
                    populateMap(o, field, builder);
                }
            } else{
                System.out.println("Field is custom type :"+ field.getName());
                Method getMethod = modelClass.getMethod("get"+ CaseFormat.LOWER_CAMEL.to(CaseFormat.UPPER_CAMEL, field.getName()));
                System.out.println("Found Getter Method :"+ getMethod);
                Object modelValue = getMethod.invoke(o, null);
                System.out.println("Model Value :"+ modelValue);
                Method setMethod = findSetterMethod(builder.getClass(), field);
                setMethod.invoke(builder, getMessage(modelValue));
            }
        }
        GeneratedMessageV3 msg = (GeneratedMessageV3) builder.build();
        return msg;
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
        throw new RuntimeException(e);
    } catch (IllegalAccessException e) {
        e.printStackTrace();
        throw new RuntimeException(e);
    } catch (InvocationTargetException e) {
        e.printStackTrace();
        throw new RuntimeException(e);
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
        throw new RuntimeException(e);
    }
}```

此代码工作正常，并将 pojo 对象转换为 protobuf 消息。但有时它会在运行时间歇性地失败 - “java.lang.IllegalArgumentException： 参数类型不匹配”

这在行失败 - “setMethod.invoke（builder， getMessage（modelValue））;”

知道如果在运行之间根本没有更改代码，为什么这会失败吗？如何摆脱/解决此异常？