Spring IOC & DI

新建项目

我们新建Maven项目名为“spring-ioc“，设置好Maven版本、配置文件以及Maven仓库

项目常用后端代码结构 如下图所示：

 

引入IOC之前

代码实现

User模块实体类：User.java

package entity;

public class User {
    private Integer id;
    private String name;
    private Integer gender;
    // 省略getter&setter方法
}

javaUser模块视图类：UserVo

package vo;

public class UserVo {
    private Integer id;
    private String name;
    private Integer gender;
    private String genderName;
    // 省略getter&setter方法
    public UserVo() {
    }
    public UserVo(User user) {
        this.id = user.getId();
        this.name = user.getName();
        this.gender = user.getGender();
    }
    // 省略toString方法
}

User模块Dao层：UserDao.java

package dao;

public interface UserDao {
    User getEntity(Integer id);
}

User模块Dao层实现类：UserDaoImpl.java

package dao.impl;

public class UserDaoImpl implements UserDao {
    public User getEntity(Integer id) {
        // 此处应该从数据库查询值 方便起见直接返回一个固定对象
        User user = new User();
        user.setId(1);
        user.setName("Anne");
        user.setGender(0);
        return user;
    }
}

User模块Service层：UserService.java

package services;

public interface UserService {
    UserVo getVo(Integer id);
}

User模块Service层实现类：UserServiceImpl.java

package services.impl;

public class UserServiceImpl implements UserService {
    private UserDao userDao;

    public UserVo getVo(Integer id) {
        // 手动实例化Dao
        userDao = new UserDaoImpl();
        // 执行Dao层方法
        User user = userDao.getEntity(id);
        // 省略业务逻辑处理。。。
        UserVo userVo = new UserVo(user);
        userVo.setGenderName(userVo.getGender() == 0 ? "female" : "male");
        return userVo;
    }
}

User模块Controller层：UserController.java

package controller;

public class UserController {
    private UserService userService;

    public UserVo getVo(Integer id) {
        // 手动实例化Service
        userService = new UserServiceImpl();
        // 执行Service层方法并返回
        return userService.getVo(id);
    }
}

User模块测试类：UserTest.java

public class UserTest {
    public static void main(String[] args) {
        // 手动实例化Controller
        UserController userController = new UserController();
        // 执行Controller层方法
        UserVo userVo = userController.getVo(1);
        System.out.println(userVo);
    }
}
测试结果
测试结果如下图所示：