废话不多说,直接上代码
一.写一个实体类
package generic;
import java.io.Serializable;
public class User implements Serializable{
/**
*
*/
private static final long serialVersionUID = 1L;
private String name;
private int age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
二.公共DAO:BaseDao(crud都写在这里)
package generic;
public abstract class BaseDao<T> {
public void save(T t){
System.out.println(".....");
}
public void delete(){
System.out.println("....");
}
}
三.DAO的具体实现:UserDa继承BaseDao
package generic;
import org.springframework.stereotype.Repository;
@Repository("userDao")
public class UserDao extends BaseDao<User>{
}
四.公共Service:BaseService(这里写一些公共方法和一个抽象方法,抽象方法为了获取BaseService的具体实现)
package generic;
public abstract class BaseService<T> {
public abstract BaseDao<T> getBaseDao();
public void save(T t){
getBaseDao().save(t);
}
}
五.写BaseService的具体实现:UserService并继承BaseService
package generic;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service("userService")
public class UserService extends BaseService<User>{
@Autowired
private UserDao userDao;
@Override
public BaseDao<User> getBaseDao() {
return userDao;
}
}
其中第四步和第五步是以前的写法,Spring4的新泻法如下:
新四:
package generic;
import org.springframework.beans.factory.annotation.Autowired;
public abstract class BaseService<T> {
@Autowired
private BaseDao<T> baseDao;
public void save(T t){
baseDao.save(t);
}
}
新五:
package generic;
import org.springframework.stereotype.Service;
@Service("userService")
public class UserService extends BaseService<User>{
}
大家可以看到现在的代码非常简洁,在步骤新四中,注入的时候spring会去自动去找BaseDao<User>的子类实现并注入
原文：http://www.cnblogs.com/shaoyang/p/6860364.html