Java Chaincode查询功能在Fabric 2.2中提供了空白的JSON响应

如何解决Java Chaincode查询功能在Fabric 2.2中提供了空白的JSON响应

我创建了Java Chaincode，并将其部署在Fabric 2.2网络上。一切似乎都正常，但是当我从分类帐中进行任何查询时，我都得到了空白的JSON响应。我在日志中没有发现任何问题，因此似乎一切正常，但是响应为空。

@Transaction()
        public Car queryCarById(final Context ctx,final String id) {
            ChaincodeStub stub = ctx.getStub();
            String CarState = stub.getStringState(id);
            if (CarState.isEmpty()) {
                String errorMessage = String.format("Car %s does not exist",id);
                System.out.println(errorMessage);
                throw new ChaincodeException(errorMessage,CarTransferErrors.Car_NOT_FOUND.toString());
            }
            Car Car = genson.deserialize(CarState,Car.class);
            System.out.println(Car);
            return Car;
        }



package Cartransfer;

import com.owlike.genson.annotation.JsonProperty;
import org.hyperledger.fabric.contract.annotation.DataType;
import org.hyperledger.fabric.contract.annotation.Property;

    @DataType()
    public final class Car {
    @Property()
    private final String id;

    @Property()
    private final String name;

    @Property()
    private final String area;

    @Property()
    private final String ownerName;
    
    @Property()
    private final String value;
    
    public String getid() {
        return id;
    }

    public String getname() {
        return name;
    }

    public String getarea() {
        return area;
    }

    public String getownerName() {
        return ownerName;
    }
    public String getvalue() {
        return value;
    }
    
    public Car(@JsonProperty("id") final String id,@JsonProperty("name") final String name,@JsonProperty("area") final String area,@JsonProperty("ownerName") final String ownerName,@JsonProperty("value") final String value) {
        this.id = id;
        this.name = name;
        this.area = area;
        this.ownerName = ownerName;this.value= value;}}

解决方法

您是否可以进行测试交易到网络（在成功部署链代码之后）？以下脚本可能有助于单独验证

https://github.com/hyperledger/fabric-samples/blob/75e3be113726d83a2de6d427608a0fec8e9b9711/test-network/scripts/deployCC.sh#L274

并使用此方法查询链式代码（以验证账本上的txn

https://github.com/hyperledger/fabric-samples/blob/75e3be113726d83a2de6d427608a0fec8e9b9711/test-network/scripts/deployCC.sh#L293