1：默认值设置 

@Table
@Data
public class DefaultValueTest {

    @TableId
    private Integer id;

    @TableField(defaultValue = "{BLANK}")
    private String value1;

    @TableField(defaultValue = "1")
    private Integer value2;

    @TableField(defaultValue = "{NOW}")
    private LocalDateTime createTime;
}

2：如何自定义默认值：

MybatisMpConfig.setDefaultValue("{NOW}", (type) -> {
    if (type == LocalDateTime.class) {
        return LocalDateTime.now();
    } else if (type == LocalDate.class) {
        return LocalDate.now();
    } else if (type == Date.class) {
        return new Date();
    } else if (type == Long.class) {
        return System.currentTimeMillis();
    } else if (type == Integer.class) {
        return (int) (System.currentTimeMillis() / 1000);
    }
    throw new RuntimeException("Inconsistent types");
});