Spring5 新手快速入门教程(含代码演示) 一、Spring5入门与注入

引言: 最近在学 Spring5 ,但网上文档类的教程复杂难入门,但b站有不少视频教程,所以打算边学边写,做个记录

推荐及资料来源尚硅谷Spring5框架教程（idea版）

1.Spring5介绍

1、Spring 是轻量级的开源的 JavaEE 框架
2、Spring 可以解决企业应用开发的复杂性
3、Spring 有两个核心部分：IOC 和 Aop
（1）IOC：控制反转，把创建对象过程交给 Spring 进行管理
（2）Aop：面向切面，不修改源代码进行功能增强
4、Spring 特点
（1）方便解耦，简化开发
（2）Aop 编程支持
（3）方便程序测试
（4）方便和其他框架进行整合
（5）方便进行事务操作
（6）降低 API 开发难度

2.Spring5 下载

Spring5 下载

3.Spring5 入门案例

初探Spring5功能,方便解耦,xml,便于类管理

<1>.创建Students类

package com.company.test;

public class Students {
    private String name;
    private String age;

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public void showStudents(){
        System.out.println(this.name+" :: "+this.age);
    }
}

<2>.创建xml文件

<3>.创建测试类,并测试

package com.company.testdemo;


import com.company.test.Students;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestStudents {
    @Test
    public void testShow() {
        //1 加载 spring 配置文件
        ApplicationContext context =
                new ClassPathXmlApplicationContext("beanTest.xml");
        //2 获取配置创建的对象
        Students students = context.getBean("students", Students.class);

        students.setName("张三");
        students.setAge("19");
        students.showStudents();
    }
}

4.属性注入 <1>.有参数构造注入属性 [1].修改Students类

package com.company.test;

public class Students {
    private String name;
    private String age;

    
    public Students(String name, String age) {
        this.name = name;
        this.age = age;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public void showStudents(){
        System.out.println(this.name+" :: "+this.age);
    }
}

[2].修改xml文件

[3].修改测试类,并测试

package com.company.testdemo;

import com.company.test.User;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestUser {
    @Test
    public void testShowUser() {
        //1 加载 spring 配置文件
        ApplicationContext context =
                new ClassPathXmlApplicationContext("beanTest.xml");
        //2 获取配置创建的对象
        User user = context.getBean("user", User.class);

//        user.setUserName("张三");
//        user.setAge("19");
        user.showUser();
    }
}

<2>.set 方法注入属性 [1].修改xml文件

```java



    
    
        
        
        
    

5.类对象注入 <1>.外部注入 [1].创建Teachers类

package com.company.test;

public class Teachers {
    private String name;
    private String subjects;

    public Teachers(String name, String subjects) {
        this.name = name;
        this.subjects = subjects;
    }

    public void showStudents(){
        System.out.println(this.name+" :: "+this.subjects);
    }
}

[2].修改Students类

package com.company.test;

public class Students {
    private String name;
    private String age;
    private Teachers teachers;//新增

    public Students(String name, String age) {
        this.name = name;
        this.age = age;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public void setTeachers(Teachers teachers) {
        this.teachers = teachers;
    }

    public void showStudents(){
        System.out.println(this.name+" :: "+this.age);
    }

    public void showTeachers(){
        this.teachers.showStudents();
    }
}

[3].修改xml文件

[4].修改测试类,并测试

package com.company.testdemo;


import com.company.test.Students;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestStudents {
    @Test
    public void testShow() {
        //1 加载 spring 配置文件
        ApplicationContext context =
                new ClassPathXmlApplicationContext("beanTest.xml");
        //2 获取配置创建的对象
        Students students = context.getBean("students", Students.class);

        students.showTeachers();
    }
}

<2>.内部注入 [1].修改xml文件