Spring batch Job read from multiple sources

Question

How can I read items from multiples databases? I already know that is possible from files.
the following example works for read from multiples files

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Answer 1

I suggest a tricky way. If we assume that one is your mysql datasource's table is base and every row in that table corresponds other mysql datasource table's row(like a join tables which are in different datasources), you could do it in your batch job itemreader. Ex of this way;

Spring DataSource Configuration;

Your batch-job.xml

    
    
    
        
            SELECT * FROM xyz
        
    



    
    
        
            SELECT * FROM abc
        
    

Your RowMapper looks like;

public class MultiDatasourceRowMapper implements RowMapper {

    private DataSource secondDataSource;

    private String secondSql;

    public String mapRow(ResultSet rs, int arg1) throws SQLException {
        Connection conn = secondDataSource.getConnection();
        PreparedStatement prep = conn.prepareStatement(secondSql); 

        // Do Something

        return "";
    }

    public void setSecondDataSource(DataSource secondDataSource) {
        this.secondDataSource = secondDataSource;
    }

    public void setSecondSql(String secondSql) {
        this.secondSql = secondSql;
    }

}