J2EE基本框架之Spring的建立，代码实现，重要jar包，spring-el

一.Spring的建立过程

1.建立Spring的配置文件--->Spring.xml

Spring 中的Bean标签

<?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:tx="http://www.springframework.org/schema/tx"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:task="http://www.springframework.org/schema/task"

       xsi:schemaLocation="http://www.springframework.org/schema/beans
						http://www.springframework.org/schema/beans/spring-beans.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 http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task.xsd">

    <bean id="stu" scope="singleton" class="com.westos.web02.bean.Student">
        <property name="xuhao" value="NO.001"></property>
        <property name="xingming" value="张三"></property>
        <property name="aihao">
            <list>
                <value>看电影</value>
                <value>购物</value>
            </list>
        </property>
        <property name="chengji">
            <map>
                <entry key="english" value="90"></entry>
                <entry key="math" value="80"></entry>
            </map>
            <!--<set>-->
                <!--<value>1</value>-->
                <!--<value>2</value>-->
            <!--</set>-->
            <!--<props>-->
                <!--<prop key="1">111</prop>-->
            <!--</props>-->
        </property>
    </bean>
    <bean id="student" scope="singleton" class="com.westos.web02.bean.Student">
        <property name="xuhao" value="NO.002"></property>
        <property name="xingming" value="李四"></property>
    </bean>
    <bean id="teacher"  class="com.westos.web02.bean.Teacher" init-method="init">
        <property name="student" ref="stu">

        </property>
        <property name="name" value="王老师"/>
    </bean>

    <bean id="teacher2" scope="singleton" class="com.westos.web02.bean.Teacher" autowire="byName">
        <property name="name" value="李老师"/>

    </bean>
    <bean id="teacher3" scope="prototype"  class="com.westos.web02.bean.Teacher" autowire="byName">
        <property name="name" value="张老师"/>

    </bean>
    <bean id="stu4" class="com.westos.web02.factory.StudentFactory" factory-method="create"></bean>
    <bean id="stu5" class="com.westos.web02.factory.StudentFactoryBean"></bean>
    <bean id="sqlSessionFactory" class="com.westos.web02.factory.MybatisFactoryBean">
        <property name="resource" value="mybatis.xml"/>
    </bean>
</beans>

2.初始化Spring的框架

package com.westos.web02.util;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * 使用单例模式初始化spring
 * Created by Administrator on 2018/8/23.
 */
public class SpringUtil {
    private static SpringUtil instance;
    private ApplicationContext context;
    private SpringUtil(){
        String filename="spring.xml";
        //初始化spring
        context = new ClassPathXmlApplicationContext(filename);
    }

    public static SpringUtil getInstance(){
        if(instance==null){
            instance=new SpringUtil();
        }
        return instance;
    }

    public Object getBean(String name){
        return context.getBean(name);
    }
    public ApplicationContext getContext(){
        return context;
    }
}

3.使用Spring来建立对象

代码示例操作如下：

student.java--->

package com.westos.web02.bean;

import java.util.List;
import java.util.Map;

/**
 * Created by Administrator on 2018/8/24.
 */
public class Student {
    private String xuhao;
    private String xingming;
    private List<String> aihao;
    private Map<String,Integer> chengji;

    @Override
    public String toString() {
        return "Student{" +
                "xuhao='" + xuhao + '\'' +
                ", xingming='" + xingming + '\'' +
                ", aihao=" + aihao +
                ", chengji=" + chengji +
                '}';
    }

    public Map<String, Integer> getChengji() {
        return chengji;
    }

    public void setChengji(Map<String, Integer> chengji) {
        this.chengji = chengji;
    }

    public List<String> getAihao() {
        return aihao;
    }

    public void setAihao(List<String> aihao) {
        this.aihao = aihao;
    }

    public String getXuhao() {
        return xuhao;
    }

    public void setXuhao(String xuhao) {
        this.xuhao = xuhao;
    }

    public String getXingming() {
        return xingming;
    }

    public void setXingming(String xingming) {
        this.xingming = xingming;
    }

}

teacher.java--->

package com.westos.web02.bean;

/**
 * Created by Administrator on 2018/8/24.
 */
public class Teacher {
    private String name;
    private Student student;
    private Student stu;

    public Student getStu() {
        return stu;
    }

    public void setStu(Student stu) {
        this.stu = stu;
    }

    @Override
    public String toString() {
        return "Teacher{" +
                "name='" + name + '\'' +
                ", student=" + student +
                ", stu=" + stu +
                '}';
    }

    public String getName() {
        return name;
    }

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

    public Student getStudent() {
        return student;
    }

    public void setStudent(Student student) {
        this.student = student;
    }

    public void init(){
        System.out.println("Teacher的初始化,"+this.getName());
    }
}

client.java --->

package com.westos.web02.util;

import com.westos.web02.bean.Student;
import com.westos.web02.bean.Teacher;

/**
 * Created by Administrator on 2018/8/24.
 */
public class Client {
    public static void main(String[] args){
        Student stu = SpringUtil.getInstance().getContext().getBean("stu",Student.class);
        System.out.println(stu.hashCode());
        Student stu2 = SpringUtil.getInstance().getContext().getBean("stu",Student.class);
        System.out.println(stu2.hashCode());
        Teacher teacher=SpringUtil.getInstance().getContext().getBean("teacher",Teacher.class);
        Teacher teacher3=SpringUtil.getInstance().getContext().getBean("teacher",Teacher.class);
        Teacher teacher4=SpringUtil.getInstance().getContext().getBean("teacher",Teacher.class);
        System.out.println(teacher.getStudent());
        System.out.println(teacher);
        System.out.println(teacher3);
        System.out.println(teacher4);
        Teacher teacher2=SpringUtil.getInstance().getContext().getBean("teacher2",Teacher.class);
        System.out.println(teacher2.getStudent());

    }
}

client2.java--->

package com.westos.web02.util;

import com.westos.web02.bean.Student;
import com.westos.web02.bean.Teacher;
import com.westos.web02.dao.HaohanDao;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

/**
 * Created by Administrator on 2018/8/24.
 */
public class Client2 {

    public static void main(String[] args){
        //单例和多例的演示
        Teacher teacher2 = SpringUtil.getInstance().getContext().getBean("teacher2", Teacher.class);
        Teacher teacher21 = SpringUtil.getInstance().getContext().getBean("teacher2", Teacher.class);
        Teacher teacher3 = SpringUtil.getInstance().getContext().getBean("teacher3", Teacher.class);
        Teacher teacher31 = SpringUtil.getInstance().getContext().getBean("teacher3", Teacher.class);
        Student stu4 = SpringUtil.getInstance().getContext().getBean("stu4", Student.class);
        Student stu5 = SpringUtil.getInstance().getContext().getBean("stu5", Student.class);
        System.out.println("teacher2:"+teacher2);
        System.out.println("teacher21:"+teacher21);
        System.out.println("teacher3:"+teacher3);
        System.out.println("teacher31:"+teacher31);
        System.out.println("stu4:"+stu4);
        System.out.println("stu5:"+stu5);
        SqlSessionFactory sqlsessionFactory = SpringUtil.getInstance().getContext().getBean(SqlSessionFactory.class);
        SqlSession sqlsession = sqlsessionFactory.openSession();
        HaohanDao dao = sqlsession.getMapper(HaohanDao.class);
        System.out.println(dao.listNews());
        sqlsession.close();
    }
}

StudentFactory.java--->factory-method

package com.westos.web02.factory;

import com.westos.web02.bean.Student;

/**
 * Created by Administrator on 2018/8/24.
 */
public class StudentFactory {

    public static Student create(){
        return new Student();
    }
}

StudentFactoryBean.java

package com.westos.web02.factory;

import com.westos.web02.bean.Student;
import org.springframework.beans.factory.FactoryBean;

/**
 * Created by Administrator on 2018/8/24.
 */
public class StudentFactoryBean implements FactoryBean<Student> {
    @Override
    public Student getObject() throws Exception {
        return new Student();
    }

    @Override
    public Class<?> getObjectType() {
        return Student.class;
    }

    @Override
    public boolean isSingleton() {
        return false;
    }
}

MybatisFactoryBean.java--->mybatis 与 FactoryBean相结合

package com.westos.web02.factory;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.springframework.beans.factory.FactoryBean;

import java.io.InputStream;

/**
 * Created by Administrator on 2018/8/24.
 */
public class MybatisFactoryBean implements FactoryBean<SqlSessionFactory> {
    private String resource;

    public String getResource() {
        return resource;
    }

    public void setResource(String resource) {
        this.resource = resource;
    }

    @Override
    public SqlSessionFactory getObject() throws Exception {

        SqlSessionFactory sqlSessionFactory=null;
        try{
            InputStream in = Resources.getResourceAsStream(resource);
            //初始化sqlSession
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        }catch (Exception ex){
            ex.printStackTrace();
        }
        return sqlSessionFactory;
    }

    @Override
    public Class<?> getObjectType() {
        return SqlSessionFactory.class;
    }

    @Override
    public boolean isSingleton() {
        return true;
    }
}

mybatis.xml文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <properties>
        <property name="driver" value="com.mysql.jdbc.Driver"/>
    </properties>
    <!--<typeAliases>-->
        <!--<typeAlias type="com.westos.web01.dao.HaohanDao" alias="hd"/>-->
    <!--</typeAliases>-->

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC">
            </transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="jdbc:mysql://localhost:3306/javaweb?useUnicode=true&amp;characterEncoding=utf-8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!--此处注意xml文件的路径及路径的大小写问题-->
        <mapper resource="com/westos/web02/dao/HaohanDao.xml"/>
        <!--<package name="com.westos.web01.dao"/>-->
    </mappers>

</configuration>

client4.java--->

4.使用Spring与westos framework整合

二.Spring的jar包

1.BeanFactory : Spring的核心jar包；

2.AplicationContext：ontext包的核心是ApplicationContext接口。它由BeanFactory接口派生而来，因而提供了BeanFactory所有的功能。

三.Spring-el表达式

package com.westos.web02.util;

import org.springframework.expression.EvaluationContext;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;

import java.util.HashMap;
import java.util.Map;

/**
 * Created by Administrator on 2018/8/24.
 */
public class Client4 {
    public static void main(String[] args){
        ExpressionParser parser = new SpelExpressionParser();
        String strel="";
        strel="'Hello World'+(1+2)";
        String result=(String)parser.parseExpression(strel).getValue();
        System.out.println(result);

        strel="#stu.xuhao"; //访问对象的属性
        strel="#stu.aihao[0]"; //访问对象属性中的列表

        EvaluationContext context=new StandardEvaluationContext();
        context.setVariable("stu",SpringUtil.getInstance().getBean("stu"));
        result=(String)parser.parseExpression(strel).getValue(context);
        System.out.println(result);
        strel="#stu.chengji[english]"; //访问对象属性中的map
        System.out.println(parser.parseExpression(strel).getValue(context));
    }
}

J2EE基本框架之Spring的建立，代码实现，重要jar包，spring-el

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