arraylist / list RESTful Web服务json

Question

Hello I want to ask about web service, how to show values from database to Map<>?

here is my code

    @GET
    @Path("/jurusan/{kode_jurusan}")
    @Produces(MediaType.APPLICATION_JSON)    
    public Map getMatkulByjurusan(@PathParam("kode_jurusan") String kode_jurusan){
        Map<String, Object> rs = new HashMap<String, Object>();
        rs.put("Pesan", "Berhasil");
        System.out.println("Jurusan "+kode_jurusan);
        try {
            createConnection();
            MyMap matkul =(MyMap) jt.queryObject("select matkul from tb_matkul where kode_jurusan = ?", new Object[] {kode_jurusan}, new MyMap());
            closeConnection();
            if(matkul != null){
                rs.put("result", matkul);
            }
        } catch (Exception e) {
            rs.put("Pesan", "Gagal karena : " +e.getMessage());
        }
        return rs;
    }

}

but when I try to acess http://localhost:9090/Service/matkul/jurusan/40 I get the following message:

{"Pesan":"Gagal karena : Incorrect result size: expected 1, actual 14"}

this MyMap class

public class MyMap implements Serializable, RowMapper{
    private static final long serialVersionUID = -8840406844877458198L;
    public HashMap<String, Object> map = new HashMap<String, Object>();

    public HashMap<String, Object> getMap() {
        return map;
    }

    public Object mapRow(ResultSet rs, int rowNum) throws SQLException {
        MyMap dto=new MyMap();
        int rowCount = rs.getMetaData().getColumnCount();
        for (int i = 1; i <= rowCount; i++) {
            dto.map.put(rs.getMetaData().getColumnLabel(i), rs.getObject(i));
        }
        return dto;
    }

    public void put(String name, Object o){
        map.put(name, o);
    }

    public Object get(String name){
        return map.get(name);
    }

    public String getString(String name){
        return (String)map.get(name);
    }

    public Integer getInt(String name){
        return (Integer)map.get(name);
    }

    public Date getDate(String name){
        return (Date)map.get(name);
    }

    public BigDecimal getBigDecimal(String name){
        return (BigDecimal)map.get(name);
    }


}

Answer 1

Use queryForList method instead queryObject .

you can find an example to map multiple rows to list using jdbcTemplate from here .

Answer 2

Looks like the problem is on the database query, as the exception says, the query is expecting only 1 row as result and it produces 14.

Moreover, depending on which framework are you using you should probably provide a way to serialize the MyMap class