[Java Web] Spring

I. Overview

Spring is a lightweight enterprise application development framework that provides control inversion (IoC) and aspect-oriented programming (AOP) technology.

Second, control reversal

Control reversal means that the relationship between programs is no longer controlled directly using code, but instead is controlled using a container. So control is transferred from program code to external container, control transfer is control inversion. Because the dependencies between program components are controlled by the container. Dependency injection is a form of inversion control that dynamically injects dependencies into components through a container during a program run. In the IOC, a configuration file describes the dependencies between objects, and no longer calls other class objects using code. During a program run, the IOC container injects dependencies between objects by loading configuration files.

Beanfactory provides the core functionality of spring, using Factory mode for reverse control and dependency injection. Read the definition of JavaBean by reading an XML file or a property file for JavaBean creation, configuration, and management. Beanfactory is generally used as a container to obtain JavaBean. Use the Beanfactory subinterface ApplicationContext to read the XML configuration file and load the JavaBean.

//Message.java PackageBean; Public classMessage {PrivateString content;  PublicString getcontent () {returncontent; }     Public voidsetcontent (String content) { This. Content =content; }}<!--beans.xml--><?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" > <beanclass= "Bean. Message "name=" message "> <property name=" Content "value=" This is a spring test! " /> </bean></beans>//Solution.javaImportBean. Message;ImportOrg.springframework.context.ApplicationContext;ImportOrg.springframework.context.support.ClassPathXmlApplicationContext; Public classSolution { Public Static voidMain (string[] args) {ApplicationContext context=NewClasspathxmlapplicationcontext ("Beans.xml"); Message Message= (message) Context.getbean ("message"));    System.out.println (Message.getcontent ()); }}

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Assignment injection.

//Company.java PackageBean; Public classCompany {Private intID; PrivateString name;  Public intgetId () {returnID; }     PublicString GetName () {returnname; }     Public voidSetId (intID) { This. ID =ID; }     Public voidsetName (String name) { This. Name =name; } @Override PublicString toString () {returnString.Format ("[%d:%s]", ID, name); }}//Worker.java PackageBean;Importjava.util.List; Public classWorker {Private intID; PrivateString name; PrivateCompany company ; PrivateList<string>Like ;  Public intgetId () {returnID; }     PublicString GetName () {returnname; }     PublicCompany Getcompany () {returnCompany ; }     PublicList<string>getlike () {returnLike ; }     Public voidSetId (intID) { This. ID =ID; }     Public voidsetName (String name) { This. Name =name; }     Public voidSetcompany (company company) { This. Company =Company ; }     Public voidSetlike (list<string>Like ) {         This. like =Like ; } @Override PublicString toString () {returnString.Format ("[%d:%s] works at%s and likes%s", ID, name, company, like); }}//Spring-config.xml<?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" > <bean id= "Comp"class= "Bean. Company "> <property name=" id "value=" 101 "/> <property name=" name "value=" Google "/> </be an> <bean id= "worker"class= "Bean. Worker "> <property name=" id "value=" 1001 "/> <property name=" name "value=" Lee "/> &LT;PR Operty name= "Company" ref= "comp"/> <property name= "like" > <list> <value >Coding</value> <value>Game</value> &LT;VALUE&GT;BASKETBALL&LT;/VALUE&G            T </list> </property> </bean></beans>//Solution.javaImportBean. Worker;ImportOrg.springframework.context.ApplicationContext;ImportOrg.springframework.context.support.ClassPathXmlApplicationContext; Public classSolution { Public Static voidMain (string[] args) {ApplicationContext context=NewClasspathxmlapplicationcontext ("Spring-config.xml"); Worker worker= (worker) Context.getbean ("worker"));    System.out.println (Worker.tostring ()); }}

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Constructor injection.

//Company.java PackageBean; Public classCompany {Private intID; PrivateString name;  PublicCompany (intID, String name) {         This. ID =ID;  This. Name =name; } @Override PublicString toString () {returnString.Format ("[%d:%s]", ID, name); }}//Worker.java PackageBean;Importjava.util.List; Public classWorker {Private intID; PrivateString name; PrivateCompany company ; PrivateList<string>Like ;  PublicWorker (intID, String name, company Company, List<string>Like ) {         This. ID =ID;  This. Name =name;  This. Company =Company ;  This. like =Like ; } @Override PublicString toString () {returnString.Format ("[%d:%s] works at%s and likes%s", ID, name, company, like); }}//Spring-config.xml<?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" > <bean id= "Comp"class= "Bean. Company "> <constructor-arg index=" 0 "value=" 101 "/> <constructor-arg index=" 1 "value=" Google "/&gt    ; </bean> <bean id= "worker"class= "Bean.        Worker "> <constructor-arg index=" 0 "value=" 1001 "/> <constructor-arg index=" 1 "value=" Lee "/>                <constructor-arg index= "2" ref= "comp"/> <constructor-arg index= "3" > <list> <value>Coding</value> <value>Game</value> <value>bas ketball</value> </list> </constructor-arg> </bean></beans>//Solution.javaImportBean. Worker;ImportOrg.springframework.context.ApplicationContext;ImportOrg.springframework.context.support.ClassPathXmlApplicationContext; Public classSolution { Public Static voidMain (string[] args) {ApplicationContext context=NewClasspathxmlapplicationcontext ("Spring-config.xml"); Worker worker= (worker) Context.getbean ("worker"));    System.out.println (Worker.tostring ()); }}

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[Java Web] Spring