MySQL string to array, merge result set, and convert to array

1. Use GROUP_CONCAT Function to merge multiple result sets

2. Use CONCAT Function to add [ ]

3. The entity class receives data

    private String id;

    private String name;

    private String[] item;

If that doesn't work , Custom annotation processing

    @TableField(typeHandler = ArrayStringTypeHandler.class, jdbcType = JdbcType.VARCHAR)
    private String[] item;

/** *  Store in database ,  take String Array to string ; *  Get data from database ,  Convert the string to LONG Array . */
@MappedTypes({
    String[].class})
@MappedJdbcTypes({
    JdbcType.VARCHAR})
public class ArrayStringTypeHandler extends BaseTypeHandler<String[]> {
    

	private static String[] l = new String[]{
    };

	@Override
	public void setNonNullParameter(PreparedStatement ps, int i,
									String[] parameter, JdbcType jdbcType) throws SQLException {
    
		ps.setString(i, JSONUtil.toJsonStr(parameter));
	}

	@Override
	public String[] getNullableResult(ResultSet rs, String columnName)
			throws SQLException {
    
		return JSONUtil.parseArray(rs.getString(columnName)).toArray(l);
	}

	@Override
	public String[] getNullableResult(ResultSet rs, int columnIndex)
			throws SQLException {
    
		return JSONUtil.parseArray(rs.getString(columnIndex)).toArray(l);
	}

	@Override
	public String[] getNullableResult(CallableStatement cs, int columnIndex)
			throws SQLException {
    
		return JSONUtil.parseArray(cs.getString(columnIndex)).toArray(l);
	}

}