專案整合說明：

 spring boot（配置多資料來源）
 spring batch

資料來源配置檔案：

@Configuration
public class DataSourceConfig {

    @Primary
    @Bean(name = "primaryDataSource")
    @ConfigurationProperties(prefix="spring.datasource.primary")
    public DataSource primaryDataSource() {
        return DataSourceBuilder.create().build();
    }

    @Bean
 
(name = "secondaryDataSource")
    @ConfigurationProperties(prefix="spring.datasource.secondary")
    public DataSource secondaryDataSource() {
        return DataSourceBuilder.create().build();
    }
}

spring batch配置檔案：

@Configuration
@EnableBatchProcessing
public class BatchConfiguration {

    //讀資料
 

    @Autowired private ReaderService readerService;
    //處理資料
    @Autowired private PersonItemProcessor processor;
    //寫資料
    @Autowired private WriterService writerService;

    @Autowired private JobBuilderFactory jobBuilderFactory;
    @Autowired private StepBuilderFactory stepBuilderFactory;

    /**
     * 異常監聽
     * @return
 

     */
    @Bean
    public JobExecutionListener listener() {
        return new JobNotification();
    }

    /**
     * 匯入任務
     */
    @Bean
    public Job importUserJob() {
        return jobBuilderFactory.get("importUserJob")
                .incrementer(new RunIdIncrementer())
                .listener(listener())
                .flow(step1())
                .end()
                .build();
    }

    /**
     * 執行步驟
     */
    @Bean
    public Step step1() {
        return stepBuilderFactory.get("step1")
                .<Person, Person> chunk(10)
                .reader( readerService.readerDatabase() )
                .processor( processor )
                .writer( writerService.writerDatabase() )
                .build();
    }
}

啟動spring boot 報錯：

***************************
APPLICATION FAILED TO START
***************************

Description:

Field dataSource in com.scp.hello.reader.ReaderService required a single bean, but 2 were found:
    - primaryDataSource: defined by method 'primaryDataSource' in class path resource [com/scp/hello/DataSourceConfig.class]
    - secondaryDataSource: defined by method 'secondaryDataSource' in class path resource [com/scp/hello/DataSourceConfig.class]


Action:

Consider marking one of the beans as @Primary, updating the consumer to accept multiple beans, or using @Qualifier to identify the bean that should be consumed


Process finished with exit code 1

異常說明：多個數據源中沒有指定一個預設資料來源。
解決方法：在一個數據源，添加註解@Primary即可。

再次啟動spring boot專案，出現異常資訊如下：

java.lang.IllegalStateException: Failed to execute CommandLineRunner
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:803) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:784) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.SpringApplication.afterRefresh(SpringApplication.java:771) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1186) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1175) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at com.scp.SpringBatchApplication.main(SpringBatchApplication.java:12) [classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_73]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_73]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_73]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_73]
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147) [idea_rt.jar:na]
Caused by: java.lang.IllegalStateException: To use the default BatchConfigurer the context must contain no more thanone DataSource, found 2
    at org.springframework.batch.core.configuration.annotation.AbstractBatchConfiguration.getConfigurer(AbstractBatchConfiguration.java:108) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
    at org.springframework.batch.core.configuration.annotation.SimpleBatchConfiguration.initialize(SimpleBatchConfiguration.java:114) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
    at org.springframework.batch.core.configuration.annotation.SimpleBatchConfiguration$ReferenceTargetSource.createObject(SimpleBatchConfiguration.java:142) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
    at org.springframework.aop.target.AbstractLazyCreationTargetSource.getTarget(AbstractLazyCreationTargetSource.java:86) ~[spring-aop-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:192) ~[spring-aop-4.3.3.RELEASE.jar:4.3.3.RELEASE]
    at com.sun.proxy.$Proxy45.getJobInstances(Unknown Source) ~[na:na]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.getNextJobParameters(JobLauncherCommandLineRunner.java:133) ~[spring-boot-autoconfigure-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.execute(JobLauncherCommandLineRunner.java:214) ~[spring-boot-autoconfigure-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.executeLocalJobs(JobLauncherCommandLineRunner.java:233) ~[spring-boot-autoconfigure-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.launchJobFromProperties(JobLauncherCommandLineRunner.java:125) ~[spring-boot-autoconfigure-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.autoconfigure.batch.JobLauncherCommandLineRunner.run(JobLauncherCommandLineRunner.java:119) ~[spring-boot-autoconfigure-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:800) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
    ... 11 common frames omitted

異常指出：To use the default BatchConfigurer the context must contain no more thanone DataSource, found 2

異常原因：spring batch啟動時，AbstractBatchConfiguration嘗試首先在Spring容器中查詢BatchConfigurer，如果沒有找到，則嘗試建立它本身， 這時在容器中找到多個DataSource 的例項，因此丟擲IllegalStateException異常。

解決方法：

@Configuration
@EnableBatchProcessing
@ComponentScan(basePackageClasses = DefaultBatchConfigurer.class)
public class BatchConfiguration {

添加註解：@ComponentScan 掃描 DefaultBatchConfigurer.class datasource注入成功。