我有 A B 两个表，结构完成一样
Apojo

@Table("a")

public class APojo {

	@Name
	protected String id; // int(11) NOT NULL

	@Column("name")
	protected String names = "名字";// char(10) NOT NULL

	@Column("age")
	protected int age;

	public String getId() {
		return id;
	}

	public void setId(String id) {
		this.id = id;
	}

	public String getNames() {
		return names;
	}

	public void setNames(String names) {
		this.names = names;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}; // int(11) NULL
	
	
}

Bpojo

@Table("b")

public class BPojo extends APojo {


	
}

业务逻辑是 假设 A中不存在某个记录， 去B表找，并且插入 A 表

@At("/feinto")
	public void feinto() {
		APojo apojo = dao.fetch(APojo.class, Cnd.where("id", "=", "479db588067e43828be9cd3f045b4d6f"));
		if (apojo == null) {
			System.out.println("null-----------------------");
			apojo = dao.fetch(BPojo.class, Cnd.where("id", "=", "479db588067e43828be9cd3f045b4d6f"));
			System.out.println(apojo.getId());
			System.out.println(apojo.getAge());
			System.out.println(apojo.getNames());
		}
		dao.insert(apojo);
	}

蛋疼的是，，，出现 id 异常，
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '479db588067e43828be9cd3f045b4d6f' for key 'PRIMARY'
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.Util.getInstance(Util.java:386)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1041)