Return multiple items from spring batch ItemReader

Question

I have data from table A like this:

ID   Name   Subject
1    AAA    music;history;math
2    BBB    music
3    CCC    math;history

and I have used ItemReader to get the list from this table:

public StoredProcedureItemReader<Student> getList() {
    StoredProcedureItemReader<Student> reader = new StoredProcedureItemReader<Student>();
    SqlParameter[] parameters = { 
            new SqlInOutParameter("v_cursor", Types.REF_CURSOR)
            };      
    reader.setDataSource(dataSource);
    reader.setProcedureName("package.GET_STUDENTLIST");
    reader.setRowMapper(new BeanPropertyRowMapper<>(Student.class));
    reader.setParameters(parameters);
    reader.setRefCursorPosition(1);   

    return reader;
}

Because of some reasons, I can't change the Stored Procedure and it will return all items in column Subject (that means the list will have 3 objects). How could I modify the StoredProcedureItemReader to return a separative item of the Subject column?
My expect is that the list should have 6 objects:

ID   Name   Subject
1    AAA    music
1    AAA    history
1    AAA    math
2    BBB    music
3    CCC    math
3    CCC    history

Answer 1

You can try to implement your custom RowMapper like below:

 StoredProcedureItemReader<List<Student>> reader = new StoredProcedureItemReader<List<Student>>();
SqlParameter[] parameters = { 
            new SqlInOutParameter("v_cursor", Types.REF_CURSOR)
            };      
    reader.setDataSource(dataSource);
    reader.setProcedureName("package.GET_STUDENTLIST");
    reader.setRowMapper(new RowMapper<List<Student>>(){  
        @Override  
        public List<Student> mapRow(ResultSet rs, int rownumber) throws SQLException { 
            String[] sub = rs.getString(3).split(";");
            List<Student> temp = new ArrayList<Student>();
            for(int i =0 ; i < sub.length ; i ++){
             Student s =new Student();  
             s.setId(rs.getInt(1));  
             s.setName(rs.getString(2)); 
             s.setSubject(sub[i]);
             temp.add(s);
            }

            return temp;  
        }  
        });  
    reader.setParameters(parameters);
    reader.setRefCursorPosition(1);   

    return reader;

Please note I have also updated ItemReader class to expect List<Student> instead of Student class and yes you can do changes accordingly to avoid run time exceptions like NullPointerException .