使用spring批处理和csv文件格式获取空指针异常向db发送数据

Posted 2023-02-16

【中文标题】使用spring批处理和csv文件格式获取空指针异常向db发送数据

【英文标题】：getting null pointer exception sending data to db using spring batch and csv file format

【发布时间】：2021-10-27 21:06:48

【问题描述】：

  package com.batch.config;

import javax.sql.DataSource;

import org.springframework.batch.core.Job;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.job.builder.JobBuilder;
import org.springframework.batch.core.launch.support.RunIdIncrementer;
import org.springframework.batch.item.database.BeanPropertyItemSqlParameterSourceProvider;
import org.springframework.batch.item.database.JdbcBatchItemWriter;
import org.springframework.batch.item.file.FlatFileItemReader;
import org.springframework.batch.item.file.LineMapper;
import org.springframework.batch.item.file.mapping.BeanWrapperFieldSetMapper;
import org.springframework.batch.item.file.mapping.DefaultLineMapper;
import org.springframework.batch.item.file.transform.DelimitedLineTokenizer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;

import com.batch.model.User;

@Configuration
@EnableBatchProcessing
public class BatchConfig 
    @Autowired
    private DataSource dataSource;
    @Autowired
    private JobBuilderFactory jobBuilderFactory;
    @Autowired
    private StepBuilderFactory stepBuildFactory;

    @Bean
    public FlatFileItemReader<User> reader() 
        FlatFileItemReader<User> reader = new FlatFileItemReader<>();
        reader.setResource(new ClassPathResource("springbachdata.csv"));
        reader.setLineMapper(getlineMapper());
        reader.setLinesToSkip(1);
        return reader;
    

    private LineMapper<User> getlineMapper() 
        DefaultLineMapper<User> lineMapper = new DefaultLineMapper<>();
        DelimitedLineTokenizer lineTokenizer = new DelimitedLineTokenizer();
        lineTokenizer.setNames(new String[]  "Emp ID", "Name Prefix", "First Name", "Last Name" );
        lineTokenizer.setIncludedFields(new int[]  0, 1, 2, 4 );
        BeanWrapperFieldSetMapper<User> fieldSetMapper = new BeanWrapperFieldSetMapper<>();
        fieldSetMapper.setTargetType(User.class);
        lineMapper.setLineTokenizer(lineTokenizer);
        lineMapper.setFieldSetMapper(fieldSetMapper);
        return lineMapper;
    

    @Bean
    public UserItemProcessor processor() 
        return new UserItemProcessor();

    

    public JdbcBatchItemWriter<User> writer() 
        JdbcBatchItemWriter<User> writer = new JdbcBatchItemWriter<>();
        writer.setItemSqlParameterSourceProvider(new BeanPropertyItemSqlParameterSourceProvider<User>());
        writer.setSql(
                "insert into user(userId,namePrefix,firstName,lastName) values (:userId, :namePrefix, :firstName, :lastName)");
        writer.setDataSource(this.dataSource);
        return writer;
    
    @Bean
    public Job importUserJob() 
        return this.jobBuilderFactory.get("USER-IMPORT-JOB")
                .incrementer(new RunIdIncrementer())
                .flow(step1())
                .end()
                .build();
                
    
@Bean
    public Step step1() 
return this.stepBuildFactory.get("step1")
.<User, User>chunk(10)
.reader(reader())
.processor(processor())
.writer(writer())
.build();
    
    

'java.lang.NullPointerException: 无法调用“org.springframework.batch.item.database.ItemPreparedStatementSetter.setValues(Object, java.sql.PreparedStatement)" 因为 “this.this$0.itemPreparedStatementSetter”在 org.springframework.batch.item.database.JdbcBatchItemWriter$1.doInPreparedStatement(JdbcBatchItemWriter.java:190) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3] 在 org.springframework.batch.item.database.JdbcBatchItemWriter$1.doInPreparedStatement(JdbcBatchItemWriter.java:186) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3] 在 org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:651) ~[spring-jdbc-5.3.9.jar:5.3.9] 在 org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:691) ~[spring-jdbc-5.3.9.jar:5.3.9] 在 org.springframework.batch.item.database.JdbcBatchItemWriter.write(JdbcBatchItemWriter.java:186) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.step.item.SimpleChunkProcessor.writeItems(SimpleChunkProcessor.java:193) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.step.item.SimpleChunkProcessor.doWrite(SimpleChunkProcessor.java:159) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.step.item.SimpleChunkProcessor.write(SimpleChunkProcessor.java:294) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.step.item.SimpleChunkProcessor.process(SimpleChunkProcessor.java:217) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.step.item.ChunkOrientedTasklet.execute(ChunkOrientedTasklet.java:77) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:407) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:331) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:140) ~[spring-tx-5.3.9.jar:5.3.9] 在 org.springframework.batch.core.step.tasklet.TaskletStep$2.doInChunkContext(TaskletStep.java:273) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.scope.context.StepContextRepeatCallback.doInIteration(StepContextRepeatCallback.java:82) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:375) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3] 在 org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3] 在 org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:145) ~[spring-batch-infrastructure-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.step.tasklet.TaskletStep.doExecute(TaskletStep.java:258) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:208) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:152) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.job.flow.JobFlowExecutor.executeStep(JobFlowExecutor.java:68) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.job.flow.support.state.StepState.handle(StepState.java:68) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.job.flow.support.SimpleFlow.resume(SimpleFlow.java:169) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.job.flow.support.SimpleFlow.start(SimpleFlow.java:144) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.job.flow.FlowJob.doExecute(FlowJob.java:137) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:320) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:149) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50) ~[spring-core-5.3.9.jar:5.3.9] 在 org.springframework.batch.core.launch.support.SimpleJobLauncher.run（SimpleJobLauncher.java:140） ~[spring-batch-core-4.3.3.jar:4.3.3] 在 java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native 方法）~[na:na] 在 java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:78) ~[na:na] 在 java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na] 在 java.base/java.lang.reflect.Method.invoke(Method.java:567) ~[na:na] 在 org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:344) ~[spring-aop-5.3.9.jar:5.3.9] 在 org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:198) ~[spring-aop-5.3.9.jar:5.3.9] 在 org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.3.9.jar:5.3.9] 在 org.springframework.batch.core.configuration.annotation.SimpleBatchConfiguration$PassthruAdvice.invoke(SimpleBatchConfiguration.java:128) ~[spring-batch-core-4.3.3.jar:4.3.3] 在 org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.9.jar:5.3.9] 在 org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215) ~[spring-aop-5.3.9.jar:5.3.9] 在 jdk.proxy2/jdk.proxy2.$Proxy58.run(Unknown Source) ~[na:na] at org.springframework.boot.autoconfigure.batch.JobLauncherApplicationRunner.execute(JobLauncherApplicationRunner.java:199) ~[spring-boot-autoconfigure-2.5.4.jar:2.5.4] 在 org.springframework.boot.autoconfigure.batch.JobLauncherApplicationRunner.executeLocalJobs(JobLauncherApplicationRunner.java:173) ~[spring-boot-autoconfigure-2.5.4.jar:2.5.4] 在 org.springframework.boot.autoconfigure.batch.JobLauncherApplicationRunner.launchJobFromProperties(JobLauncherApplicationRunner.java:160) ~[spring-boot-autoconfigure-2.5.4.jar:2.5.4] 在 org.springframework.boot.autoconfigure.batch.JobLauncherApplicationRunner.run(JobLauncherApplicationRunner.java:155) ~[spring-boot-autoconfigure-2.5.4.jar:2.5.4] 在 org.springframework.boot.autoconfigure.batch.JobLauncherApplicationRunner.run(JobLauncherApplicationRunner.java:150) ~[spring-boot-autoconfigure-2.5.4.jar:2.5.4] 在 org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:782) ~[spring-boot-2.5.4.jar:2.5.4] 在 org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:772) ~[spring-boot-2.5.4.jar:2.5.4] 在 org.springframework.boot.SpringApplication.run(SpringApplication.java:345) ~[spring-boot-2.5.4.jar:2.5.4] 在 org.springframework.boot.SpringApplication.run(SpringApplication.java:1343) ~[spring-boot-2.5.4.jar:2.5.4] 在 org.springframework.boot.SpringApplication.run(SpringApplication.java:1332) ~[spring-boot-2.5.4.jar:2.5.4] 在 com.batch.CsvTomysqlApplication.main(CsvToMysqlApplication.java:10) ~[classes/:na]

[2m2021-08-28 10:24:36.741[0;39m [32m INFO[0;39m [35m10388[0;39m [2m---[0;39m [2m[主][0;39m [36mo.s.batch.core.step.AbstractStep [0;39m [2m:[0;39m 步骤：[step1] 在 72ms 内执行 [2m2021-08-28 10:24:36.768[0;39m [32m 信息[0;39m [35m10388[0;39m [2m---[0;39m [2m[ 主][0;39m [36mo.s.b.c.l.support.SimpleJobLauncher [0;39m [2m:[0;39m Job: [FlowJob: [name=USER-IMPORT-JOB]] 完成 以下参数：[run.id=4] 和以下状态：[FAILED] 在 134 毫秒内'

块引用

【问题讨论】：

您没有包含 NPE 所在的特定类，但很可能问题在于它不是 Spring bean。避免使用@Autowired 字段；通常将它们替换为构造函数或（在@Bean 方法的情况下）参数。

谢谢你的回复，但我没有得到你的正确答案，你能解释一下吗，非常感谢

请修剪您的代码，以便更容易找到您的问题。请按照以下指南创建minimal reproducible example。

【参考方案1】：

请将 LineMapper 方法设为 public 并添加 @Bean 注解。还要在 JdbcBatchItemWriter 方法上方添加@Bean 注解。

@Bean
public LineMapper<User> getlineMapper() 
        DefaultLineMapper<User> lineMapper = new DefaultLineMapper<>();
        DelimitedLineTokenizer lineTokenizer = new DelimitedLineTokenizer();
        lineTokenizer.setNames(new String[]  "Emp ID", "Name Prefix", "First Name", "Last Name" );
        lineTokenizer.setIncludedFields(new int[]  0, 1, 2, 4 );
        BeanWrapperFieldSetMapper<User> fieldSetMapper = new BeanWrapperFieldSetMapper<>();
        fieldSetMapper.setTargetType(User.class);
        lineMapper.setLineTokenizer(lineTokenizer);
        lineMapper.setFieldSetMapper(fieldSetMapper);
        return lineMapper;
    

@Bean
public JdbcBatchItemWriter<User> writer() 
        JdbcBatchItemWriter<User> writer = new JdbcBatchItemWriter<>();
        writer.setItemSqlParameterSourceProvider(new BeanPropertyItemSqlParameterSourceProvider<User>());
        writer.setSql(
                "insert into user(userId,namePrefix,firstName,lastName) values (:userId, :namePrefix, :firstName, :lastName)");
        writer.setDataSource(this.dataSource);
        return writer;
    

【参考方案2】：

为简单起见，使用一个单独的临时用户类作为 UserInput 来读取数据和一个表示表 e.i *User 实体的实体类

用户输入

public class UserInput 

    private String userId;
    private String namePrefix;
    private String firstName;
    private String lastName;

用户

@Entity
@Table(name = "USER")
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User 
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;
    private String userId;
    private String namePrefix;
    private String firstName;
    private String lastName;        

用户数据处理器

public class UserDataProcessor implements ItemProcessor<UserInput, User> 

    @Override
    public User process(UserInput userInput) throws Exception 
        User user = new User();
        user.setUserId(userInput.getUserId());
        user.setNamePrefix(userInput.getNamePrefix());
        user.setFirstName(userInput.getFirstName());
        user.setLastName(userInput.getLastName());
        System.out.println(user);
        return user;
    

批量配置

    @Configuration
    @EnableBatchProcessing
    public class BatchConfig 
    
        private final String[] FIELD_NAMES = new String[]  "userId", "namePrefix", "firstName", "lastName" ;
    
        @Autowired
        private DataSource dataSource;
        @Autowired
        private JobBuilderFactory jobBuilderFactory;
        @Autowired
        private StepBuilderFactory stepBuilderFactory;
    
        @Bean
        public FlatFileItemReader<UserInput> reader() 
            return new FlatFileItemReaderBuilder<UserInput>().name("personItemReader")
                    .resource(new ClassPathResource("user-data.csv")).delimited().names(FIELD_NAMES)
                    .fieldSetMapper(new BeanWrapperFieldSetMapper<UserInput>() 
                        
                            setTargetType(UserInput.class);
                        
                    ).build();
        
    
        @Bean
        public UserDataProcessor processor() 
            return new UserDataProcessor();
    
        
        @Bean
        public JdbcBatchItemWriter<User> writer() 
            return new JdbcBatchItemWriterBuilder<User>()
                    .itemSqlParameterSourceProvider(new BeanPropertyItemSqlParameterSourceProvider<>())
                    .sql("INSERT INTO user (userId,namePrefix,firstName,lastName) "
                            + "VALUES (:userId,:namePrefix,:firstName,:lastName)")
                    .dataSource(dataSource).build();
    
        
    
        @Bean
        public Job importUserJob(JobCompletionNotificationListener listener, Step step1) 
            return jobBuilderFactory.get("importUserJob").incrementer(new RunIdIncrementer()).listener(listener).flow(step1)
                    .end().build();
        
    
        @Bean
        public Step step1(JdbcBatchItemWriter<User> writer) 
            return stepBuilderFactory.get("step1").<UserInput, User>chunk(10).reader(reader()).processor(processor())
                    .writer(writer).build();