1) Spring_HelloWorld

2022-10-16 07:23:58

1. Spring Tool Suite™

方式一：下载对应eclipse版本的文件，离线安装

4.4.2 springsource-tool-suite-3.6.4.RELEASE-e4.4.2-updatesite.zip 87MB

选择

Core / Spring IDE
Extensions / Spring IDE
Integrations / Spring IDE
Resources / Spring IDE

方式二：在线安装 install new sorftware - add site

2. 创建maven项目

导入spring jar包

<dependencies>

    <dependency>

        <groupId>org.springframework</groupId>

        <artifactId>spring-context</artifactId>

        <version>4.1.6.RELEASE</version>

    </dependency>

</dependencies>

spring-aop
spring-beans
spring-context
spring-core
spring-expression
commons-logging
aopalliance

创建IoC 容器配置文件

<?xml version="1.0" encoding="UTF-8"?>

<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">

    <beans>

        <bean id="person" class="cn.zno.hello.Person" >

            <property name="name" value="XiaoMing"></property>

            <property name="age" value="22"></property>

            <property name="savings" value="10000"></property>

            <property name="car" ref="car"></property>

        </bean>

        <bean id="car" class="cn.zno.hello.Car">

            <property name="brand" value="BYD"></property>

            <property name="price" value="54000"></property>

        </bean>

    </beans>

</beans>

Person.java

package cn.zno.hello;

public class Person {

    private String name;

    private int age;

    private double savings;

    private Car car;

    public void say(){

        System.out.println("Hello World!");

    }

    // -------------getter & setter-------------

    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;

    }

    public double getSavings() {

        return savings;

    }

    public void setSavings(double savings) {

        this.savings = savings;

    }

    public Car getCar() {

        return car;

    }

    public void setCar(Car car) {

        this.car = car;

    }

    @Override

    public String toString() {

        return "Person [name=" + name + ", age=" + age + ", savings=" + savings

                + ", car=" + car + "]";

    }

}

Car.java

package cn.zno.hello;

public class Car {

    private String brand;

    private double price;

    public String getBrand() {

        return brand;

    }

    public void setBrand(String brand) {

        this.brand = brand;

    }

    public double getPrice() {

        return price;

    }

    public void setPrice(double price) {

        this.price = price;

    }

    @Override

    public String toString() {

        return "Car [brand=" + brand + ", price=" + price + "]";

    }

}

Main.java

package cn.zno.hello;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Main {

    @SuppressWarnings("resource")

    public static void main(String[] args) {

//        /*传统方式*/

//        Person person = new Person();

//        person.setName("XiaoMing");

//        person.setAge(22);

//        person.setSavings(10000);

//        //-->

//        Car car = new Car();

//        car.setBrand("BYD");

//        car.setPrice(50000);

//        //<--

//        person.setCar(car);

//

//        System.out.println(person);

//        person.say();

        /*IoC*/

        ApplicationContext ctx = new ClassPathXmlApplicationContext("beans-hello.xml");

        Person person = (Person) ctx.getBean("person");

        System.out.println(person);

        person.say();

    }

}

Console:

六月 ,  :: 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh

信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@1ef7de4: startup date [Tue Jun  :: CST ]; root of context hierarchy

六月 ,  :: 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions

信息: Loading XML bean definitions from class path resource [beans-hello.xml]

Person [name=XiaoMing, age=, savings=10000.0, car=Car [brand=BYD, price=54000.0]]

Hello World!

注意问题：

applicationContext.xml 是借助sts生成

ApplicationContext ctx; 应该记死！其实现类可Ctrl+T | F4 查询

└─src

    └─main

        ├─java

        │  └─cn

        │      └─zno

        │          └─hello

        │                  Car.java

        │                  Main.java

        │                  Person.java

        │

        └─resources

                beans-hello.xml

常见错误：

1. xml文件不存在

六月 ,  :: 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh

信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@14e4e31: startup date [Tue Jun  :: CST ]; root of context hierarchy

六月 ,  :: 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions

信息: Loading XML bean definitions from class path resource [beans-hello1.xml]

Exception in thread "main" org.springframework.beans.factory.BeanDefinitionStoreException: IOException parsing XML document from class path resource [beans-hello1.xml]; nested exception is java.io.FileNotFoundException: class path resource [beans-hello1.xml] cannot be opened because it does not exist

    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:)

    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:)

    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:)

    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:)

    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:)

    at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:)

    at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:)

    at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:)

    at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:)

    at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:)

    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:)

    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:)

    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:)

    at cn.zno.hello.Main.main(Main.java:)

Caused by: java.io.FileNotFoundException: class path resource [beans-hello1.xml] cannot be opened because it does not exist

    at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:)

    at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:)

    ...  more

2.xml文件中bean未配置

六月 ,  :: 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh

信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@1ef7de4: startup date [Tue Jun  :: CST ]; root of context hierarchy

六月 ,  :: 上午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions

信息: Loading XML bean definitions from class path resource [beans-hello.xml]

Exception in thread "main" org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'person1' is defined

    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:)

    at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:)

    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:)

    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:)

    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:)

    at cn.zno.hello.Main.main(Main.java:)

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