java - 一个 ItemReader，2 个 SQL Query，jdbcTemplate？

Question

我有一个要求，我从数据库中读取两个不同的Query. 每个Query都有自己的SQL. 它们是相似的SQLs，并且在大多数情况下都在使用相同的表集，但差异很小。我想检查我是否可以有两个SQLs或者ItemReader使用 ajdbctemplate是可能的？

任何想法，示例代码？

score 2 · Accepted Answer

如果您想“重用”现有的JdbcCursorItemReader（或其他 Spring Batch Jdbc*ItemReaders 之一），您可以通过利用 step 范围动态切换 SQL。下面是一个配置示例，它sqlKey根据JobParameters. 声明的来源是一张简单的地图。

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:batch="http://www.springframework.org/schema/batch"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd
        http://www.springframework.org/schema/batch http://www.springframework.org/schema/batch/spring-batch.xsd">

    <batch:job id="switchSQL">
        <batch:step id="switchSQL.step1">
            <batch:tasklet>
                <batch:chunk reader="sqlItemReader" writer="outItemWriter" commit-interval="10"/>
            </batch:tasklet>
        </batch:step>
    </batch:job>

    <bean id="sqlItemReader"
        class="org.springframework.batch.item.database.JdbcCursorItemReader" scope="step">
        <property name="dataSource" ref="dataSource"/>
        <property name="sql" value="#{@sqlStatements[jobParameters['sqlKey']]}"/>
        <property name="rowMapper">
            <bean class="de.incompleteco.spring.batch.data.ColumnRowMapper"/>
        </property>
    </bean>

    <util:map id="sqlStatements">
        <entry key="sql1" value="select * from table_one"/>
        <entry key="sql2" value="select * from table_two"/>
    </util:map>

    <bean id="outItemWriter"
        class="org.springframework.batch.item.adapter.ItemWriterAdapter">
        <property name="targetObject" ref="outWriter"/>
        <property name="targetMethod" value="write"/>
    </bean>

    <bean id="outWriter" class="de.incompleteco.spring.batch.item.SystemOutItemWriter"/>
</beans>

这是支持类；

（一个简单的项目作家）

package de.incompleteco.spring.batch.item;

public class SystemOutItemWriter {

    public void write(Object object) {
        System.out.println(object);
    }

}

（和一个简单的行映射器）

package de.incompleteco.spring.batch.data;

import java.sql.ResultSet;
import java.sql.SQLException;

import org.springframework.jdbc.core.RowMapper;

public class ColumnRowMapper implements RowMapper<String> {

    public String mapRow(ResultSet rs, int rowNum) throws SQLException {
        return rs.getString(1);
    }

}

这是剩余的配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">


    <bean id="jobRepository"
        class="org.springframework.batch.core.repository.support.MapJobRepositoryFactoryBean"/>

    <bean id="jobExplorer"
        class="org.springframework.batch.core.explore.support.MapJobExplorerFactoryBean">
        <property name="repositoryFactory" ref="&amp;jobRepository"/>
    </bean>

    <bean id="jobLauncher"
        class="org.springframework.batch.core.launch.support.SimpleJobLauncher">
        <property name="jobRepository" ref="jobRepository"/>
    </bean>


    <bean id="transactionManager"
        class="org.springframework.batch.support.transaction.ResourcelessTransactionManager">
    </bean>

    <bean class="org.springframework.batch.core.scope.StepScope"/>
</beans>

和

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd">


    <jdbc:embedded-database id="dataSource" type="H2">
        <jdbc:script location="classpath:/META-INF/sql/schema-h2.sql"/>
        <jdbc:script location="classpath:/META-INF/sql/insert-h2.sql"/>
    </jdbc:embedded-database>

    <bean id="dataSourceTransactionManager"
        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>
</beans>

和 sql 的东西

create table table_one (
    column_a varchar(50)
);

create table table_two (
    column_a varchar(50)
);

--table one
insert into table_one (column_a) values ('hello');
insert into table_one (column_a) values ('world');

--table two
insert into table_two (column_a) values ('hey');

现在终于进行单元测试

package de.incompleteco.spring;

import static org.junit.Assert.assertFalse;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.JobParametersBuilder;
import org.springframework.batch.core.explore.JobExplorer;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration({"classpath:/META-INF/spring/*-context.xml"})
public class SwitchSQLIntegrationTest {

    @Autowired
    private Job job;

    @Autowired
    private JobLauncher jobLauncher;

    @Autowired
    private JobExplorer jobExplorer;

    @Test
    public void test() throws Exception {
        //setup the parameters
        JobParameters parameters = new JobParametersBuilder().addLong("runtime",System.currentTimeMillis())
                .addString("sqlKey", "sql1").toJobParameters();
        //run
        JobExecution execution = jobLauncher.run(job,parameters);
        //test
        while (jobExplorer.getJobExecution(execution.getId()).isRunning()) {
            Thread.sleep(100);
        }//end while
        //load
        execution = jobExplorer.getJobExecution(execution.getId());
        //test
        assertFalse(execution.getStatus().isUnsuccessful());
        //run it again
        parameters = new JobParametersBuilder().addLong("runtime",System.currentTimeMillis())
                .addString("sqlKey", "sql2").toJobParameters();
        //run
        execution = jobLauncher.run(job,parameters);
        //test
        while (jobExplorer.getJobExecution(execution.getId()).isRunning()) {
            Thread.sleep(100);
        }//end while
        //load
        execution = jobExplorer.getJobExecution(execution.getId());
        //test
        assertFalse(execution.getStatus().isUnsuccessful());        
    }

}

java - 一个 ItemReader，2 个 SQL Query，jdbcTemplate？

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