core.convert.ConverterNotFoundException：未找到能够将[com.prateek.model.Product]类型转换为[java.lang.String]类型的转换器

Question

我开发了 Spring Batch示例，在这个项目中，它从Mysql中读取数据并将其写入Redis DB。

我创建了一个自定义编写器，该编写器将以下数据写入redis，而在编写时，该错误低于错误

2018-07-17 00:58:59 DEBUG o.s.b.core.step.tasklet.TaskletStep - Applying contribution: [StepContribution: read=100, written=0, filtered=0, readSkips=0, writeSkips=0, processSkips=0, exitStatus=EXECUTING]
2018-07-17 00:58:59 DEBUG o.s.b.core.step.tasklet.TaskletStep - Rollback for RuntimeException: org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [com.prateek.model.Product] to type [java.lang.String]
2018-07-17 00:58:59 DEBUG o.s.t.support.TransactionTemplate - Initiating transaction rollback on application exception
org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [com.prateek.model.Product] to type [java.lang.String]
    at org.springframework.core.convert.support.GenericConversionService.handleConverterNotFound(GenericConversionService.java:321)
    at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:194)
    at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:174)
    at org.springframework.data.redis.serializer.GenericToStringSerializer$Converter.convert(GenericToStringSerializer.java:120)
    at org.springframework.data.redis.serializer.GenericToStringSerializer.serialize(GenericToStringSerializer.java:88)
    at org.springframework.data.redis.core.AbstractOperations.rawHashValue(AbstractOperations.java:184)
    at org.springframework.data.redis.core.DefaultHashOperations.put(DefaultHashOperations.java:175)
    at com.prateek.writer.ProductRedisWriter.write(ProductRedisWriter.java:24)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:338)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:197)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163)
    at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:136)
    at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:124)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)
    at com.sun.proxy.$Proxy8.write(Unknown Source)
    at org.springframework.batch.core.step.item.SimpleChunkProcessor.writeItems(SimpleChunkProcessor.java:185)
    at org.springframework.batch.core.step.item.SimpleChunkProcessor.doWrite(SimpleChunkProcessor.java:151)
    at org.springframework.batch.core.step.item.SimpleChunkProcessor.write(SimpleChunkProcessor.java:284)
    at org.springframework.batch.core.step.item.SimpleChunkProcessor.process(SimpleChunkProcessor.java:209)
    at org.springframework.batch.core.step.item.ChunkOrientedTasklet.execute(ChunkOrientedTasklet.java:75)
    at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:406)
    at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:330)
    at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:140)
    at org.springframework.batch.core.step.tasklet.TaskletStep$2.doInChunkContext(TaskletStep.java:272)
    at org.springframework.batch.core.scope.context.StepContextRepeatCallback.doInIteration(StepContextRepeatCallback.java:81)
    at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:375)
    at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215)
    at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:145)
    at org.springframework.batch.core.step.tasklet.TaskletStep.doExecute(TaskletStep.java:257)
    at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:200)
    at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:148)
    at org.springframework.batch.core.job.flow.JobFlowExecutor.executeStep(JobFlowExecutor.java:66)
    at org.springframework.batch.core.job.flow.support.state.StepState.handle(StepState.java:67)
    at org.springframework.batch.core.job.flow.support.SimpleFlow.resume(SimpleFlow.java:169)
    at org.springframework.batch.core.job.flow.support.SimpleFlow.start(SimpleFlow.java:144)
    at org.springframework.batch.core.job.flow.FlowJob.doExecute(FlowJob.java:136)
    at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:308)
    at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:141)
    at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50)
    at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:134)
    at com.prateek.App.main(App.java:29)
2018-07-17 00:58:59 DEBUG o.s.b.s.t.ResourcelessTransactionManager - Initiating transaction rollback

尝试写入的数据：

  

Product（productCode = S10_1678，productName = 1969 Harley Davidson Ultimate Chopper，productLine = Motorcycles，productScale = 1：10，productVendor = Min Lin Diecast，productDescription =此复制品具有工作支架，前悬架，变速杆和脚刹杆，传动链，车轮和转向装置。由于零件的精确比例，所有零件都特别精致，需要特别的保养和注意。，quantageInStock = 7933，buyPrice = 48.81，MSRP = 95.7）

ProductRedisWriter.java

@Repository
public class ProductRedisWriter implements ItemWriter<Product>{

    @Resource(name="redisTemplate")
    private HashOperations<String, String, Product> hashOps;     

    @Override
    public void write(List<? extends Product> products) throws Exception {

        for (Product product : products) {
            System.out.println("Prodcus saved to Redis  "+product.toString());
            hashOps.put("Product", product.getProductCode(), product);
        }
    }
}

Product.java

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class Product {
    private String productCode;
    private String productName;
    private String productLine;
    private String productScale;
    private String productVendor;
    private String productDescription;
    private Integer quantityInStock;
    private Double buyPrice;
    private Double MSRP;
}

database.xml

<bean id="keySerializer" class="org.springframework.data.redis.serializer.StringRedisSerializer" />
<bean id="hashKeySerializer" class="org.springframework.data.redis.serializer.StringRedisSerializer" />
<bean id="hashValueSerializer" class="org.springframework.data.redis.serializer.GenericToStringSerializer" >
    <constructor-arg name="type" value="java.lang.String" />
</bean>
<bean id="valueSerializer" class="org.springframework.data.redis.serializer.GenericToStringSerializer" >
    <constructor-arg name="type" value="java.lang.String" />
</bean>

<!-- redis template definition -->
<bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate" 
    p:enableTransactionSupport="true"
    p:connection-factory-ref="jedisConnectionFactory"
    p:keySerializer-ref="keySerializer"
    p:hashKeySerializer-ref="hashKeySerializer"
    p:valueSerializer-ref="valueSerializer"
    p:hashValueSerializer-ref="hashValueSerializer" />

MySQL数据：