Unable to write to FlatFile in spring batch - only object reference are getting write to flat file

Question

I'm working on Spring Batch Composite Writer Example. Here I'm trying to read two tables data using compositeItemReader and write to CSV file using FlatFileItemWriter. In doing this when I am running main program I only sees output like below it only giving me object reference not values.

com.common.batch.model.Customer@1615682
com.common.batch.model.Customer@176ad02
com.common.batch.model.Customer@5883fc
com.common.batch.model.Customer@1411cbf
com.common.batch.model.Customer@1c66b53
com.common.batch.model.Customer@f459a4
com.common.batch.model.Customer@293404
com.common.batch.model.Customer@115fae6
com.common.batch.model.Customer@b1298
com.common.batch.model.Customer@f1df22
com.common.batch.model.Customer@c13eca
com.common.batch.model.Customer@1015199
com.common.batch.model.Customer@1943319
com.common.batch.model.Customer@a6bf88
com.common.batch.model.Customer@1687e27
com.common.batch.model.Customer@1bbd50b
com.common.batch.model.Customer@9fd887
com.common.batch.model.Customer@40af64
com.common.batch.model.Customer@baff9a
com.common.batch.model.Customer@e2f388
com.common.batch.model.Customer@10472ac
com.common.batch.model.Customer@10480e1

I expect to see all fields values successfully. Employee.java

public class Employee implements Serializable{
    private static final long serialVersionUID = 1L;

    private Integer employeeNumber;
    private String lastName;
    private String firstName;
    private String extension;
    private String email;
    private String officeCode;
    private Integer reportsTo;
    private String jobTitle;


    public Integer getEmployeeNumber() {
        return employeeNumber;
    }
    public void setEmployeeNumber(Integer employeeNumber) {
        this.employeeNumber = employeeNumber;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public String getFirstName() {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getExtension() {
        return extension;
    }
    public void setExtension(String extension) {
        this.extension = extension;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getOfficeCode() {
        return officeCode;
    }
    public void setOfficeCode(String officeCode) {
        this.officeCode = officeCode;
    }
    public Integer getReportsTo() {
        return reportsTo;
    }
    public void setReportsTo(Integer reportsTo) {
        this.reportsTo = reportsTo;
    }
    public String getJobTitle() {
        return jobTitle;
    }
    public void setJobTitle(String jobTitle) {
        this.jobTitle = jobTitle;
    }
}

Customer.java

public class Customer implements Serializable{
    private static final long serialVersionUID = 1L;

    private Integer customerNumber;
    private String customerName;
    private String contactLastName;
    private String contactFirstName;
    private String phone;
    private String addressLine1;
    private String addressLine2;
    private String city;
    private String state;
    private String postalCode;
    private String country;
    private Integer salesRepEmployeeNumber;
    private Double creditLimit;


    public Integer getCustomerNumber() {
        return customerNumber;
    }
    public void setCustomerNumber(Integer customerNumber) {
        this.customerNumber = customerNumber;
    }
    public String getCustomerName() {
        return customerName;
    }
    public void setCustomerName(String customerName) {
        this.customerName = customerName;
    }
    public String getContactLastName() {
        return contactLastName;
    }
    public void setContactLastName(String contactLastName) {
        this.contactLastName = contactLastName;
    }
    public String getContactFirstName() {
        return contactFirstName;
    }
    public void setContactFirstName(String contactFirstName) {
        this.contactFirstName = contactFirstName;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    public String getAddressLine1() {
        return addressLine1;
    }
    public void setAddressLine1(String addressLine1) {
        this.addressLine1 = addressLine1;
    }
    public String getAddressLine2() {
        return addressLine2;
    }
    public void setAddressLine2(String addressLine2) {
        this.addressLine2 = addressLine2;
    }
    public String getCity() {
        return city;
    }
    public void setCity(String city) {
        this.city = city;
    }
    public String getState() {
        return state;
    }
    public void setState(String state) {
        this.state = state;
    }
    public String getPostalCode() {
        return postalCode;
    }
    public void setPostalCode(String postalCode) {
        this.postalCode = postalCode;
    }
    public String getCountry() {
        return country;
    }
    public void setCountry(String country) {
        this.country = country;
    }
    public Integer getSalesRepEmployeeNumber() {
        return salesRepEmployeeNumber;
    }
    public void setSalesRepEmployeeNumber(Integer salesRepEmployeeNumber) {
        this.salesRepEmployeeNumber = salesRepEmployeeNumber;
    }
    public Double getCreditLimit() {
        return creditLimit;
    }
    public void setCreditLimit(Double creditLimit) {
        this.creditLimit = creditLimit;
    }
}

job.xml

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

    <import resource="classpath:context-datasource.xml" />

    <!-- JobRepository and JobLauncher are configuration/setup classes -->
    <bean id="jobRepository" class="org.springframework.batch.core.repository.support.MapJobRepositoryFactoryBean" />

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


    <!-- Step will need a transaction manager -->
    <bean id="transactionManager" class="org.springframework.batch.support.transaction.ResourcelessTransactionManager" />


    <job id="compositeJdbcReaderJob" xmlns="http://www.springframework.org/schema/batch">
        <step id="compositeJdbcReaderStep" next="compositeJdbcReaderStep2">
            <tasklet>
                <chunk reader="compositeItemReader" writer="itemWriter" commit-interval="5" />
            </tasklet>
        </step>

        <step id="compositeJdbcReaderStep2">
            <tasklet>
                <chunk reader="compositeItemReader2" writer="itemWriter2" commit-interval="5" />
            </tasklet>
        </step>
    </job>

    <bean id="compositeItemReader" class="com.common.batch.reader.CompositeCursorItemReader">
        <property name="unifyingMapper">
            <bean class="com.common.batch.mapper.DefaultUnifyingStringItemsMapper" />
        </property>
        <property name="cursorItemReaders">
            <list>
                <ref bean="itemReader1" />
            </list>
        </property>
    </bean>

    <bean id="compositeItemReader2" class="com.common.batch.reader.CompositeCursorItemReader">
        <property name="unifyingMapper">
            <bean class="com.common.batch.mapper.DefaultUnifyingStringItemsMapper" />
        </property>
        <property name="cursorItemReaders">
            <list>
                <ref bean="itemReader2" />                 
            </list>
        </property>
    </bean>


    <bean id="itemReader1" class="org.springframework.batch.item.database.JdbcCursorItemReader">
        <property name="dataSource" ref="dataSource" />

        <property name="saveState" value="true" />

        <property name="sql">
            <value>
                <![CDATA[ ${select.sql.customers} ]]>
            </value>
        </property>
        <property name="rowMapper">
            <bean class="com.common.batch.mapper.CustomerMapper" />
        </property>
    </bean>


    <bean id="itemReader2" class="org.springframework.batch.item.database.JdbcCursorItemReader">
        <property name="dataSource" ref="dataSource" />

        <property name="saveState" value="true" />

        <property name="sql">
            <value>
                <![CDATA[ ${select.sql.employees} ]]>
            </value>
        </property>
        <property name="rowMapper">
            <bean class="com.common.batch.mapper.EmployeeMapper" />
        </property>
    </bean>


    <bean id="itemWriter" class="org.springframework.batch.item.file.FlatFileItemWriter" scope="step">
        <property name="resource" value="${output.file.location}" />
        <!-- <property name="appendAllowed" value="true" /> -->
        <property name="lineAggregator">
            <bean class="org.springframework.batch.item.file.transform.PassThroughLineAggregator"/>
        </property>
    </bean>


    <bean id="itemWriter2" class="org.springframework.batch.item.file.FlatFileItemWriter" scope="step">
        <property name="resource" value="${output.file.location}" />
        <property name="appendAllowed" value="true" />
        <property name="lineAggregator">
            <bean class="org.springframework.batch.item.file.transform.PassThroughLineAggregator"/>
        </property>
    </bean>
</beans>

Main.java

public class CompositeMain {
    @SuppressWarnings("resource")
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("job.xml");

        JobLauncher jobLauncher = (JobLauncher) context.getBean("jobLauncher");
        Job job = (Job) context.getBean("compositeJdbcReaderJob");

        JobExecution execution;
        try {
            execution = jobLauncher.run(job, new JobParameters());
            System.out.println("Job Exit Status : "+ execution.getStatus());

        } catch (JobExecutionAlreadyRunningException | JobRestartException
                | JobInstanceAlreadyCompleteException | JobParametersInvalidException e) {
            System.out.println(e.getMessage());
            e.printStackTrace();
        }
        System.out.println("Done !!");
    }
}

I expect Flat file should be write like say example:

firstValue | secondValue | thirdValue ...

Per suggestion from Michael, I developed XML file below:

<bean id="itemWriter" class="org.springframework.batch.item.file.FlatFileItemWriter" scope="step">
        <property name="resource" value="${output.file.location}" />
        <!-- <property name="appendAllowed" value="true" /> -->
        <property name="lineAggregator">
            <bean class="org.springframework.batch.item.file.transform.DelimitedLineAggregator">
                <property name="delimiter" value="|" />
                <property name="fieldExtractor">
                    <!-- Extractor which returns the value of beans property through reflection -->
                    <bean class="org.springframework.batch.item.file.transform.BeanWrapperFieldExtractor">
                        <property name="names" value="customerNumber,customerName,contactLastName,contactFirstName,phone,addressLine1,addressLine2,city,state,postalCode,country,salesRepEmployeeNumber,creditLimit" />
                    </bean>
                </property>
            </bean>
        </property>
    </bean>


    <bean id="itemWriter2" class="org.springframework.batch.item.file.FlatFileItemWriter" scope="step">
        <property name="resource" value="${output.file.location}" />
        <property name="appendAllowed" value="true" />
       <property name="lineAggregator">
            <bean class="org.springframework.batch.item.file.transform.DelimitedLineAggregator">
                <property name="delimiter" value="|" />
                <property name="fieldExtractor">
                    <!-- Extractor which returns the value of beans property through reflection -->
                    <bean class="org.springframework.batch.item.file.transform.BeanWrapperFieldExtractor">
                        <property name="names" value="employeeNumber,lastName,firstName,extension,email,officeCode,reportsTo,jobTitle" />
                    </bean>
                </property>
            </bean>
        </property>
    </bean>

Answer 1

you are using PassThroughLineAggregator (emphasize mine)

The most basic implementation of the LineAggregator interface is the PassThroughLineAggregator, which simply assumes that the object is already a string, or that its string representation is acceptable for writing

either change to a specific LineAggregator or adjust the toString method of your objects to output the way you want it to be