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第二章 IoC 構造器注入
UserDao與UserDaoImpl:
public interface UserDao {
public void save();
}
public class UserDaoImpl implements UserDao {
public void save() {
System.out.println("保存用戶...");
}
}
UserService接口及其實現類UserServiceImpl:
public interface UserService {
public void addUser();
}
public class UserServiceImpl implements UserService {
private UserDao userDao;
private String username;
//這裏的成員變量不需要setter方法。這是與setter注入不同的地方
public UserServiceImpl(UserDao userDao, String username) {
this.userDao = userDao;
this.username = username;
}
public void addUser() {
System.out.println(username);
userDao.save();
}
}
配置:
<bean ></bean> <!-- index表示的是構造方法中的第幾個參數。從0開始。 --> <bean > <constructor-arg index="0" ref="userDao"></constructor-arg> <constructor-arg index="1" value="zhangsan"></constructor-arg> </bean>
最後更新：2017-04-03 16:48:30