• DI的几种注入方式

    前言: 时间有限，课程赶得太紧，明天还要学习新的内容，这是我参考网上的教程，写的很粗糙，可能不便于阅读，后期再做完善吧┭┮﹏┭┮

    1.setter注入以及简单数据类型注入

    1.环境准备

    image-20221109221055860

    创建接口和实现类BookDao、BookDaoImpl、UserDao、UserDaoImpl、BookService、BookServiceImpl

    package com.hnu.dao;
//先创建接口，然后创建实现类，最后在App类中引用实现
public interface BookDao {
    public void save();
}



package com.hnu.dao.impl;
import com.hnu.dao.BookDao;
//实现接口
public class BookDaoImpl implements BookDao {
    private String databaseName;
    private int connectionNum;
    public void setDatabaseName(String databaseName) {
        this.databaseName = databaseName;
    }
    public void setConnectionNum(int connectionNum) {
        this.connectionNum = connectionNum;
    }
    public void save() {
        System.out.println("book dao save " + databaseName + "  " + connectionNum);
    }
}



package com.hnu.dao;
public interface UserDao {
    public void save();
}




package com.hnu.dao.impl;
import com.hnu.dao.UserDao;
public class UserDaoImpl implements UserDao {
    public void save() {
        System.out.println("user dao save ...");
    }
}




package com.hnu.service;
public interface BookService {
    public void save();
}






package com.hnu.service.impl;
import com.hnu.dao.BookDao;
import com.hnu.dao.UserDao;
import com.hnu.service.BookService;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;

public class BookServiceImpl implements BookService {
    //在这个实现类中也可以创建bookDao接口的对象，在接口中是不能创建对象的，接口中存放的是方法
    private BookDao bookDao;
    private UserDao userDao;
    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }
    public void setBookDao(BookDao bookDao) {
        this.bookDao = bookDao;
    }
    public void save() {
        System.out.println("book service save ...");
        bookDao.save();
        userDao.save();
    }
}

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    2.声明属性并提供setter方法

    3.配置文件中进行注入配置

    
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="bookDao" class="com.hnu.dao.impl.BookDaoImpl">
        <!---注入简单数据类型->
        <property name="connectionNum" value="6"/>
        <property name="databaseName" value="pgsql"/>
    bean>
    <bean id="useDao" class="com.hnu.dao.impl.UserDaoImpl"/>

    <bean id="bookService" class="com.hnu.service.impl.BookServiceImpl">
        
        
        
        <property name="bookDao" ref="bookDao"/>
        <property name="userDao" ref="useDao"/>
    bean>
beans>

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    4.运行程序

    AppForDISet

    package com.hnu;

import com.hnu.service.BookService;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class AppForDISet {
    public static void main(String[] args) {
        ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
        BookService bookService = (BookService)ctx.getBean("bookService");
        bookService.save();
        //ctx.close();
        ctx.registerShutdownHook();
    }
}

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    image-20221109221530442

    2.构造器注入引用数据类型和简单数据类型

    1.环境准备

    image-20221109222010084

    创建相应的接口和实现类BookDao、BookDaoImpl、UserDao、UserDaoImpl、BookService、BookServiceImpl

    package com.hnu.dao;
//先创建接口，然后创建实现类，最后在App类中引用实现
public interface BookDao {
    public void save();
}




package com.hnu.dao.impl;
import com.hnu.dao.BookDao;
//实现接口
public class BookDaoImpl implements BookDao {
    private String databaseName;
    private int connectionNum;

    public BookDaoImpl(String databaseName, int connectionNum) {
        this.databaseName = databaseName;
        this.connectionNum = connectionNum;
    }
    public void save() {
        System.out.println("book dao save " + databaseName + "  " + connectionNum);
    }
}




package com.hnu.dao;
public interface UserDao {
    public void save();
}



package com.hnu.dao.impl;
import com.hnu.dao.UserDao;
public class UserDaoImpl implements UserDao {
    public void save() {
        System.out.println("user dao save ...");
    }
}




package com.hnu.service;
public interface BookService {
    public void save();
}





package com.hnu.service.impl;
import com.hnu.dao.BookDao;
import com.hnu.dao.UserDao;
import com.hnu.service.BookService;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
public class BookServiceImpl implements BookService {
    //在这个实现类中也可以创建bookDao接口的对象，在接口中是不能创建对象的，接口中存放的是方法
    private BookDao bookDao;
    private UserDao userDao;
    public BookServiceImpl(BookDao bookDao, UserDao userDao) {
        this.bookDao = bookDao;
        this.userDao = userDao;
    }
    public void save() {
        System.out.println("book service save ...");
        bookDao.save();
        userDao.save();
    }
}

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    2.注入引用数据类型和简单数据类型

    3.配置文件中进行注入配置

    
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="bookDao" class="com.hnu.dao.impl.BookDaoImpl">
        
        

        

        
        
        <constructor-arg index="0" value="pgsql"/>
        <constructor-arg index="1" value="6"/>
    bean>
    <bean id="userDao" class="com.hnu.dao.impl.UserDaoImpl"/>

    
    
    <bean id="bookService" class="com.hnu.service.impl.BookServiceImpl">
        <constructor-arg name="bookDao" ref="bookDao"/>
        <constructor-arg name="userDao" ref="userDao"/>
    bean>

beans>

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    4.运行程序

    AppForDIConstructor

    package com.hnu;

import com.hnu.service.BookService;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class AppForDIConstructor {
    public static void main(String[] args) {
        ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
        BookService bookService = (BookService)ctx.getBean("bookService");
        bookService.save();
        //ctx.close();
        ctx.registerShutdownHook();
    }
}


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    image-20221109222336882

    3.自动配置

    5.3.2 自动装配方式有哪些?

    • 按类型（常用）
    • 按名称
    • 按构造方法
    • 不启用自动装配

    1.准备环境

    image-20221109222733606

    创建接口和实现类BookDao、BookDaoImpl、UserDao、UserDaoImpl、BookService、BookServiceImpl

    package com.hnu.dao;

//先创建接口，然后创建实现类，最后在App类中引用实现
public interface BookDao {
    public void save();
}






package com.hnu.dao.impl;
import com.hnu.dao.BookDao;
//实现接口
public class BookDaoImpl implements BookDao {
    private String databaseName;
    private int connectionNum;

    public BookDaoImpl(String databaseName, int connectionNum) {
        this.databaseName = databaseName;
        this.connectionNum = connectionNum;
    }
    public void setDatabaseName(String databaseName) {
        this.databaseName = databaseName;
    }
    public void setConnectionNum(int connectionNum) {
        this.connectionNum = connectionNum;
    }
    public void save() {
        System.out.println("book dao save " + databaseName + "  " + connectionNum);
    }
}




package com.hnu.dao;
public interface UserDao {
    public void save();
}





package com.hnu.dao.impl;
import com.hnu.dao.UserDao;
public class UserDaoImpl implements UserDao {
    public void save() {
        System.out.println("user dao save ...");
    }
}



package com.hnu.service;
public interface BookService {
    public void save();
}




package com.hnu.service.impl;
import com.hnu.dao.BookDao;
import com.hnu.dao.UserDao;
import com.hnu.service.BookService;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
public class BookServiceImpl implements BookService {
    //在这个实现类中也可以创建bookDao接口的对象，在接口中是不能创建对象的，接口中存放的是方法
    private BookDao bookDao;
    public void setBookDao(BookDao bookDao) {
        this.bookDao = bookDao;
    }
    public void save() {
        System.out.println("book service save ...");
        bookDao.save();
    }
}

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    2.引用数据类型和简单数据类型的自动注入bytype

    3.完成自动配置的xml配置

    
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    
    
    <bean class="com.hnu.dao.impl.BookDaoImpl">
        <constructor-arg index="0" value="pgsql"/>
        <constructor-arg index="1" value="6"/>
    bean>
    <bean class="com.hnu.dao.impl.UserDaoImpl"/>

    <bean id="bookService" class="com.hnu.service.impl.BookServiceImpl" autowire="byType"/>
beans>

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    3.运行程序

    AppForDIAutoSet

    package com.hnu;

import com.hnu.service.BookService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class AppForDIAutoSet {
    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
        BookService bookService = (BookService)ctx.getBean("bookService");
        bookService.save();
    }
}


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    运行结果:

    image-20221109223130776

    4.集合注入

    环境准备

    image-20221109223336304

    创建接口和实现类BookDao、BookDaoImpl

    package com.hnu.dao;
//先创建接口，然后创建实现类，最后在App类中引用实现
public interface BookDao {
    public void save();
}





package com.hnu.dao.impl;
import com.hnu.dao.BookDao;
import java.util.*;
//实现接口
public class BookDaoImpl implements BookDao {
    private int[] array;

    private List<String> list;

    private Set<String> set;

    private Map<String, String> map;

    private Properties properties;

    public void setArray(int[] array) {
        this.array = array;
    }

    public void setList(List<String> list) {
        this.list = list;
    }

    public void setSet(Set<String> set) {
        this.set = set;
    }

    public void setMap(Map<String, String> map) {
        this.map = map;
    }

    public void setProperties(Properties properties) {
        this.properties = properties;
    }

    public void save() {
        System.out.println("book dao save ...");

        System.out.println("遍历数组:" + Arrays.toString(array));

        System.out.println("遍历List" + list);

        System.out.println("遍历Set" + set);

        System.out.println("遍历Map" + map);

        System.out.println("遍历Properties" + properties);

    }
}

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    2.引入spring依赖

    <dependencies>
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-contextartifactId>
            <version>5.2.10.RELEASEversion>
        dependency>
        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <version>4.12version>
            <scope>testscope>
        dependency>
    dependencies>

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    3.xml配置

    
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="bookDao" class="com.hnu.dao.impl.BookDaoImpl">
        <property name="array">
            
            <array>
                <value>100value>
                <value>200value>
                <value>300value>
            array>
        property>

        <property name="list">
            
            <list>
                <value>htuvalue>
                <value>hnuvalue>
                <value>mukewangvalue>
                <value>bokeyuanvalue>
            list>
        property>

        <property name="set">
            
            <set>
                <value>htuvalue>
                <value>hnuvalue>
                <value>mukewangvalue>
                <value>bokeyuanvalue>
            set>
        property>

        <property name="map">
            
            <map>
                <entry key="country" value="china"/>
                <entry key="province" value="henan"/>
                <entry key="city" value="kaifeng"/>
            map>
        property>

        <property name="properties">
            
            <props>
                <prop key="country">chinaprop>
                <prop key="province">henanprop>
                <prop key="city">kaifengprop>
            props>
        property>
    bean>
beans>

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    4.运行程序AppForDICollection

    package com.hnu;

import com.hnu.dao.BookDao;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class AppForDICollection {
    public static void main(String[] args) {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
        BookDao bookDao = (BookDao)ctx.getBean("bookDao");
        bookDao.save();
    }
}


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    运行结果:

    image-20221109224249737

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  • 原文地址：https://blog.csdn.net/weixin_51470901/article/details/127779727