Spring Batch 如何编写 Map

Question

i've already seen a lot of tutorials and spring material but i have found only examples that contains a simple object in the ItemWriter.

For example...

    @Bean
    JdbcBatchItemWriter<Student> writer = new JdbcBatchItemWriter<>();
    writer.setItemSqlParameterSourceProvider(new BeanPropertyItemSqlParameterSourceProvider<Student>());
    writer.setItemPreparedStatementSetter(new ItemPreparedStatementSetter<Student>(){
        @Override
        public void setValues(Student student, PreparedStatement ps) throws SQLException {
            ps.setLong(1,student.getStudentCode());
            ps.setObject(2,student.getStudentGrade());
        }});
    writer.setSql(QUERY_STUDENT_GRADE_INSERT);
    writer.setDataSource(dataSource);
    return writer;  

in my actual scenario i must write a Map that contains a key and a value like:

Map<KeyObject,Long>

But i have no idea how to code something that be able to insert all the content that i've received in my Map.

There's another question...

When i process certain number of items i need to store this data in the database, but the previous content stay in my collection, that way... how can i clean the map content after write ?

Answer 1

The solution was replace my Map for a List

I'm just using lambda to filter the objects in the list and writing them through the common itemWriter.