一、xml方式创建对象
<!-- 配置User对象创建--> <!-- id是取得别名，通过id别名可以把类找到--> <bean id="user" class="com.atguigu.spring5.User"></bean>
- id：唯一标识，不能加特殊符号
- class：类全路经（包类路径）
- name：可以加特殊符号
二、xml方式注入属性
DI：依赖注入，就是注入属性
第①种方式注入：set方法注入
package com.atguigu.spring5.Book; public class Book { private String bname; private String bauthor; public void setBname(String bname){ this.bname=bname; } public void setBauthor(String bauthor){ this.bauthor=bauthor; } public static void main(String[] args) { Book book = new Book(); book.setBname("abc"); } public void testDemo(){ System.out.println(bname+"---"+bauthor); } }
<?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"> <!-- 2.set方法注入属性--> <bean id="book" class="com.atguigu.spring5.Book.Book"> <!-- 使用propterty完成属性注入--> <!-- name：类里面属性名称--> <!-- value：向属性注入的值--> <property name="bname" value="追风筝的人"></property> <property name="bauthor" value="卡勒德·胡赛尼"></property> </bean> </beans>
package com.atguigu.spring5.Book; import org.springframework.context.ApplicationContext; import org.springframework.context.annotation.AnnotationConfigApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class BoolTestMain { public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("Booktest.xml"); Book book = context.getBean("book", Book.class); System.out.println(book); book.testDemo(); } }
我们还可以通过另一种方式简化写法—p名称空间注入
第②种方式注入：有参构造函数注入
public class Orders { // 有参数构造注入属性 private String oname; private String address; private double money; public Orders(String oname, String address, double money) { this.oname = oname; this.address = address; this.money = money; } public void show() { System.out.println(oname + "---" + address + "---" + money); } }
constructor-arg：通过构造函数注入
使用value标签属性： 默认按照constructor-arg标签的顺序
<constructor-arg value="电脑"></constructor-arg> <constructor-arg value="China"></constructor-arg>
用name标签属性： 不按照顺序也会自动匹配
<constructor-arg name="oname" value="电脑"></constructor-arg> <constructor-arg name="address" value="China"></constructor-arg>
使用index标签属性：index的值为参数的顺序，默认从0开始
<!--index="0"：有参构造的第一个属性--> <constructor-arg index="0" value="电脑"></constructor-arg> <constructor-arg index="1" value="China"></constructor-arg>
使用type标签属性：要和参数数据类型严格一致
（如果数据类型一致，按照constructor-arg标签的顺序匹配）
<constructor-arg type="double" value="23"></constructor-arg> <constructor-arg type="java.lang.String" value="电脑"></constructor-arg> <constructor-arg type="java.lang.String" value="China"></constructor-arg>
三、xml注入其他类型属性
1、字面量--null值
<constructor-arg name="oname" value="朝花夕拾"/> <constructor-arg name="oauthor" value="鲁迅"/> <constructor-arg name="address" > <null></null> </constructor-arg>
2、含有特殊符号
- <；>；
- 把带特殊符号内容写到!CDATA
<!-- 1、使用<>先进行转义--> <property name="bauthor" value="鲁迅"></property> <property name="bname" value="<>朝花夕拾>>"></property> <!-- 2、使用!CDATA--> <property name="bauthor"> <value><![CDATA[<<南京>>]]></value> </property>
3、注入属性-外部bean
通过ref属性将进行注入
public class School { //创建School类型属性，生成set方法 private Teacher teacher; public void setTeacher(Teacher teacher) { this.teacher = teacher; } }
<!-- 注入外部bean--> <bean id="school" class="com.atguigu.spring5.propertyTest.School"> <property name="teacher" ref="teachers"></property> </bean> <bean id="teachers" class="com.atguigu.spring5.propertyTest.Teacher"></bean>
4、注入属性-内部bean
什么是内部bean？
在某一个bean中定义另一个bean作为属性
什么时候使用内部bean？
如果School类中的某个属性的数据类型是另一个类Book，则可以把这个类Book定义在属性的内部
如何使用内部bean？
public class School { //创建School类型属性，生成set方法 private Teacher teacher; public void setTeacher(Teacher teacher) { this.teacher = teacher; } //部门 private Book dept; public void setDept(Book dept) { this.dept = dept; } }
public class Book { private String bname; private String bauthor; public void setBname(String bname) { this.bname = bname; } }
<!-- 注入内部bean--> <bean id="school" class="com.atguigu.spring5.propertyTest.School"> <property name="teacher" ref="teachers"></property> <property name="dept" > <bean id="book" class="com.atguigu.spring5.Book.Book"> <property name="bname" value="朝花夕拾"></property> </bean> </property> </bean>
5、注入集合属性——数组、List集合、Map集合、Set集合
package com.atguigu.spring5.CollectionTypeTest; import java.util.Arrays; import java.util.List; import java.util.Map; import java.util.Set; /** * @BelongsProject: 02-Spring * @BelongsPackage: com.atguigu.spring5.CollectionTypeTest * @Author: dengLiMei * @CreateTime: 2023-02-09 09:46 * @Description: TODO * @Version: 1.0 */ public class Student { //数组 private String[] courses; // List集合 private List<String> lists; //Map集合 private Map<String, String> maps; //Set集合 private Set<String> sets; public void setSets(Set<String> sets) { this.sets = sets; } public Student() { } public void setCourses(String[] courses) { this.courses = courses; } public void setLists(List<String> lists) { this.lists = lists; } public void setMaps(Map<String, String> maps) { this.maps = maps; } public void show() { System.out.println(Arrays.toString(courses)); System.out.println((lists)); System.out.println((maps)); System.out.println((sets)); } }
<?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="students" class="com.atguigu.spring5.CollectionTypeTest.Student"> <!-- 数组--> <property name="courses"> <array> <value>spring5</value> <value>springboot</value> </array> </property> <!-- List类型--> <property name="lists"> <list> <value>springcloud</value> <value>springcloudAlibaba</value> </list> </property> <!-- Map集合--> <property name="maps"> <map> <entry key="QQ" value="腾讯"></entry> <entry key="淘宝" value="阿里"></entry> </map> </property> <!-- Set集合--> <property name="sets"> <set> <value>set-spring5</value> <value>set-springboot</value> </set> </property> </bean> </beans>
输出结果：
如果一个类中包含了另一个类的实体对象，可以这样写
public class Course { // 课程名称 private String cname; public void setCname(String cname) { this.cname = cname; } }
package com.atguigu.spring5.CollectionTypeTest; import java.util.Arrays; import java.util.List; import java.util.Map; import java.util.Set; public class Student2 { //实体对象-学生有多门课程 private List<Course> courseList; public void setCourseList(List<Course> courseList) { this.courseList = courseList; } @Override public String toString() { return "Student2{" + "courseList=" + courseList + '}'; } }
<bean id="student2" class="com.atguigu.spring5.CollectionTypeTest.Student2"> <property name="courseList"> <list> <ref bean="course1"></ref> <ref bean="course2"></ref> </list> </property> </bean> <!-- 创建多个course对象--> <bean id="course1" class="com.atguigu.spring5.CollectionTypeTest.Course"> <property name="cname" value="spring5框架"></property> </bean> <bean id="course2" class="com.atguigu.spring5.CollectionTypeTest.Course"> <property name="cname" value="MyBatis框架"></property> </bean>
public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("CollectionTypeBeans.xml"); Student2 students1 = context.getBean("student2", Student2.class); students1.show(); }
输出结果：
目前的问题：只能当前类使用，其他类不能用，接下来就是把集合属性抽取成公共部分让所有实体类都能够引入
抽取公共部分
public class Book { private List<String> list; public void setList(List<String> list) { this.list = list; } public void show(){ System.out.println(list); } }
<?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:util="http://www.springframework.org/schema/util" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd"> <!-- 1、提取list集合类型属性注入--> <util:list id="bookList"> <value>spring5</value> <value>springboot</value> <value>springcloud</value> </util:list> <!-- 2、提取list集合类型属性注入使用--> <bean id="book" class="com.atguigu.spring5.CollectionTypeTest.Book"> <property name="list" ref="bookList"></property> </bean> </beans>
public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("CollectionTypeBeans.xml"); Book book = context.getBean("book", Book.class); book.show(); }
输出结果：
