Hyperledger fabric 错误：如何在hyperledger链码中编写getHistoryForKey（）方法以获取键的历史记录（java语言）

我已将以下方法写入我的hyperledger链码（智能合约）中，以基于键获取历史记录（所有交易数据）

@Transaction（intent=Transaction.TYPE.EVALUATE）
公共ArrayList queryProductHistory（最终上下文ctx，最终字符串productNumber）{
if（productNumber==null）{
抛出新的RuntimeException（“未给出ID”）；
}
ChaincodeStub stub=ctx.getStub（）；
ArrayList结果=新建ArrayList（）；
试一试{
QueryResultsIterator history=stub.getHistoryForKey（productNumber）；
如果（历史==null）{
String errorMessage=String.format（“产品%s不存在”，产品编号）；
System.out.println（错误消息）；
抛出新的ChaincodeException（errorMessage，MySmartContractErrors.PRODUCT_NOT_FOUND.toString（））；
}
迭代器iter=history.Iterator（）；
while（iter.hasNext（））{
添加（iter.next（）.getStringValue（））；
}
}捕获（例外e）{
results.add（e.getMessage（））；
添加（例如getCause（）.getMessage（））；
添加（例如getStackTrace（）.toString（））；
}
返回结果；
}

我还为上述方法编写了一个API，

@RequestMapping（value=“查找产品历史”，method=RequestMethod.GET）
公共字符串queryProductHistory（@RequestParam（value=“channelName”）字符串channelName，@RequestParam（value=“productNumber”）字符串productNumber）引发异常{
//加载基于文件系统的钱包以管理身份。
Path walletPath=Path.get（“钱包”）；
Wallet Wallet=Wallets.newFileSystemWallet（walletPath）；
//加载CCP
Path networkConfigPath=Path.get（“/home”、“ubuntu”、“fabric samples”、“test network”、“organizations”、“peerOrganizations”、“org1.example.com”、“connection-org1.yaml”）；
Gateway.Builder=Gateway.createBuilder（）；
builder.identity（wallet，“appUser”）.networkConfig（networkConfigPath）.discovery（true）；
//创建网关连接
try（网关=builder.connect（））{
//获得网络和合同
Network=gateway.getNetwork（channelName）；
合同合同=network.getContract（“我的区块链智能合同”）；
字节[]结果；
结果=contract.evaluateTransaction（“queryProductHistory”，productNumber）；
System.out.println（新字符串（结果））；
返回result.toString（）；
}
}

我遇到以下错误。这里可能有什么问题？

org.hyperledger.fabric.gateway.ContractException: error in simulation: transaction returned with failure: Unexpected error
at org.hyperledger.fabric.gateway.impl.query.SingleQueryHandler.evaluate(SingleQueryHandler.java:50) ~[fabric-gateway-java-2.1.1.jar:na]
at org.hyperledger.fabric.gateway.impl.TransactionImpl.evaluate(TransactionImpl.java:207) ~[fabric-gateway-java-2.1.1.jar:na]
at org.hyperledger.fabric.gateway.impl.ContractImpl.evaluateTransaction(ContractImpl.java:55) ~[fabric-gateway-java-2.1.1.jar:na]
at com.my.blockchain.api.controller.BlockchainAPIController.queryProductHistory(BlockchainAPIController.java:137) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_275]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_275]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_275]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_275]
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:197) ~[spring-web-5.3.2.jar:5.3.2]
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:141) ~[spring-web-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:106) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:894) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1061) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:961) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.2.jar:5.3.2]
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.2.jar:5.3.2]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:626) ~[tomcat-embed-core-9.0.41.jar:4.0.FR]
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.2.jar:5.3.2]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:733) ~[tomcat-embed-core-9.0.41.jar:4.0.FR]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.2.jar:5.3.2]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.2.jar:5.3.2]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.2.jar:5.3.2]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.2.jar:5.3.2]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.2.jar:5.3.2]
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.3.2.jar:5.3.2]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) [tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542) [tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) [tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) [tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) [tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:888) [tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1597) [tomcat-embed-core-9.0.41.jar:9.0.41]
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.41.jar:9.0.41]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_275]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_275]
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.41.jar:9.0.41]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_275]

注意：我在core.xml中也做了

启用历史数据库：true

现在工作正常。
下面是chaincode

queryProductHistory（）

方法中的更正

@Transaction
    public String queryProductHistory(final Context ctx, final String productNumber) {
        if (productNumber == null) {
            throw new RuntimeException("No ID given");
        }
        ChaincodeStub stub = ctx.getStub();
        ArrayList<String> results = new ArrayList<>();
        try {
            QueryResultsIterator<KeyModification> history = stub.getHistoryForKey(productNumber);
            
            if (history == null) {
                String errorMessage = String.format("Product %s does not exist", productNumber);
                System.out.println(errorMessage);
                throw new ChaincodeException(errorMessage, MySmartContractErrors.PRODUCT_NOT_FOUND.toString());
            }
            Iterator<KeyModification> iterator = history.iterator();
            while (iterator.hasNext()) {
                String iteratorValue = iterator.next().getStringValue();
                //String iteratorValue = "TIMESTAMP = " + iterator.next().getTimestamp() + "Tx ID = " + iterator.next().getTxId() + " VALUE = " + iterator.next().getStringValue();
                results.add(iteratorValue);
                
                System.out.println(iteratorValue);
            }
            history.close();
        } catch (Exception e) {
            results.add(e.getMessage());
            results.add(e.getCause().getMessage());
            results.add(e.getStackTrace().toString());
        }
        return results.toString();
    } 

@RequestMapping(value = "find-product-history", method = RequestMethod.GET) public String queryProductHistory(@RequestParam(value="channelName") String channelName, @RequestParam(value="productNumber") String productNumber) throws Exception {

    // Load a file system based wallet for managing identities.
    Path walletPath = Paths.get("wallet");
    Wallet wallet = Wallets.newFileSystemWallet(walletPath);
    // load a CCP
    Path networkConfigPath = Paths.get("/home", "ubuntu", "fabric-samples", "test-network", "organizations", "peerOrganizations",
            "org1.example.com", "connection-org1.yaml");

    Gateway.Builder builder = Gateway.createBuilder();
    builder.identity(wallet, "appUser").networkConfig(networkConfigPath).discovery(true);

    // create a gateway connection
    try (Gateway gateway = builder.connect()) {

        // get the network and contract
        Network network = gateway.getNetwork(channelName);
        Contract contract = network.getContract("my-blockchain-smart-contract");

        byte[] result;

        result = contract.evaluateTransaction("queryProductHistory", productNumber);
        //result = contract.submitTransaction("queryProductHistory", productNumber);

        System.out.println(new String(result));

        return new String(result);
    }
}