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  • Spring学习笔记(一)

    Spring学习笔记(一)

    Spring核心思想:

    IOC:  Inversion Of Control (控制反转) / DI: Dependency Injection (依赖注入)

    AOP: Aspect Oriented Programming (面向切面编程)


    IOC

    1. 简单的应用

    Model

    package com.wangj.spring.model;
    
    public class User {
        private String username;
        private String password;
    
        public String getUsername() {
            return username;
        }
    
        public void setUsername(String username) {
            this.username = username;
        }
    
        public String getPassword() {
            return password;
        }
    
        public void setPassword(String password) {
            this.password = password;
        }
    }
    View Code

    Dao

    package com.wangj.spring.dao;
    
    import com.wangj.spring.model.User;
    
    public interface UserDao {
        void save(User user);
    }
    View Code

    DaoImpl

    package com.wangj.spring.dao.impl;
    
    import com.wangj.spring.dao.UserDao;
    import com.wangj.spring.model.User;
    
    public class UserDaoImpl implements UserDao {
        @Override
        public void save(User user) {
            System.out.println(String.format("user(%s) saved!", user.getUsername()));
        }
    }
    View Code

    Service

    package com.wangj.spring.service;
    
    import com.wangj.spring.dao.UserDao;
    import com.wangj.spring.model.User;
    
    public class UserService {
        private UserDao userDao;
    
        public void add(User user) {
            userDao.save(user);
        }
    
        public UserDao getUserDao() {
            return userDao;
        }
    
        public void setUserDao(UserDao userDao) {
            this.userDao = userDao;
        }
    }
    View Code

    jar

    applicationContext.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" xmlns:aop="http://www.springframework.org/schema/aop"
        xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context"
        xmlns:tx="http://www.springframework.org/schema/tx"
        xsi:schemaLocation="
                http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
                http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
                http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
        
        <bean id="userDao" class="com.wangj.spring.dao.impl.UserDaoImpl">
        </bean>
        
        <bean id="userService" class="com.wangj.spring.service.UserService">
            <property name="userDao" ref="userDao"></property>
        </bean>
    </beans>
    View Code

    test

    package com.wangj.spring;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.FileSystemXmlApplicationContext;
    
    import com.wangj.spring.model.User;
    import com.wangj.spring.service.UserService;
    
    public class SpringDemo {
        public static void main(String[] args) {
            ApplicationContext applicationContext = new FileSystemXmlApplicationContext("config/applicationContext.xml");
            
            UserService service = (UserService) applicationContext.getBean("userService");
            
            User user = new User();
            user.setUsername("wangj");
            user.setPassword("wangj1130");
            service.add(user);
        }
    }
    View Code

    2. 具体用法(XML配置)

    • bean注入方法
    1. set方法注入
    
    <bean id="userService" class="com.wangj.spring.service.UserService">
        <property name="userDao" ref="userDao"></property>
    </bean>
    
    2. 构造方法注入
    <bean id="userService" class="com.wangj.spring.service.UserService">
    <constructor-arg>
        <ref bean="userDao"/>
        <!-- <bean class="com.wangj.test.spring.dao.impl.UserDaoImpl"/> --> <!-- 重新new对象 -->
    </constructor-arg>
    </bean>
    
    当构造方法里含有多个参数时:
    1)根据类型
    <bean id="exampleBean" class="examples.ExampleBean">
        <constructor-arg type="int" value="7500000"/>
        <constructor-arg type="java.lang.String" value="42"/>
    </bean>
    2)根据顺序
    <bean id="exampleBean" class="examples.ExampleBean">
        <constructor-arg index="0" value="7500000"/>
        <constructor-arg index="1" value="42"/>
    </bean>
    • bean scope属性:

      scope="singleton" //(默认)每次使用同一个对象

         ="prototype" //每次都new一个新的(Struts Action)

         =request、session、global session(不重要)

    • 集合注入
    <bean name="userDAO" class="com.wangj.dao.impl.UserDAOImpl">
          <property name="sets">
              <set>
                  <value>1</value>
                  <value>2</value>
              </set>
          </property>
          <property name="lists">
              <list>
                  <value>1</value>
                  <value>2</value>
                  <value>3</value>
              </list>
          </property>
          <property name="maps">
              <map>
                  <entry key="1" value="1"></entry>
                  <entry key="2" value="2"></entry>
                  <entry key="3" value="3"></entry>
                  <entry key="4" value="4"></entry>
              </map>
          </property>
    </bean>
    • autowire 自动装配

      autowire="byName" // 根据名称自动装配,该名称为setXxx()方法中xxx(set后的字符串首字母小写),与变量名无关

          ="byType" // 根据类型自动装配

          ="default" // 跟<beans 节点中 default-autowire属性一致,如果<beans节点中未配置default-autowire属性,则报异常

    • bean生命周期

      lazy-init="true" // 什么时用到什么时候初始化(sping初始化默认将所有bean加载到内存)

      init-method="init" // 容器初始化时调用

      destroy-method="destroy" // 容器销毁时调用

      (init-method、destroy-method 一般不和prototype一起用)

      

    作者:踮起脚尖眺望
    出处:http://www.cnblogs.com/wangj1130
    本文版权归作者所有,欢迎转载,但未经作者同意必须保留此段声明,且在文章页面明显位置给出原文连接,否则保留追究法律责任的权利。
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  • 原文地址:https://www.cnblogs.com/wangj1130/p/4899392.html
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