网站被做跳转怎么办,个人网站开发软件,凡客t恤,了解深圳网站页面设计一、Ioc 控制反转 控制反转是一种思想 控制反转是为了降低程序耦合度#xff0c;提高程序扩展力#xff0c;达到 OCP 原则#xff0c;达到 DIP 原则 控制反转#xff0c;反转的是什么#xff1f; 将对象的创建权利交出去#xff0c;交给第三方容器负责 将对象和对象之…一、Ioc 控制反转 控制反转是一种思想 控制反转是为了降低程序耦合度提高程序扩展力达到 OCP 原则达到 DIP 原则 控制反转反转的是什么 将对象的创建权利交出去交给第三方容器负责 将对象和对象之间关系的维护权交出去交给第三方容器负责 控制反转这种思想如何实现呢 DIDependency Injection依赖注入 二、依赖注入
依赖注入实现了控制反转的思想
Spring通过依赖注入的方式来完成Bean管理的
Bean管理说的是Bean对象的创建以及Bean对象中属性的赋值或者叫做Bean对象之间关系的维护 依赖注入 依赖指的是对象和对象之间的关联关系 注入指的是一种数据传递行为通过注入行为来让对象和对象产生关系 依赖注入常见的实现方式包括两种 第一种set 注入 第二种构造注入 三、set 注入
set 注入基于 set 方法实现的底层会通过反射机制调用属性对应的set方法然后给属性赋值。这种方式要求属性必须对外提供 set 方法
?xml version1.0 encodingUTF-8?
project xmlnshttp://maven.apache.org/POM/4.0.0xmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsdmodelVersion4.0.0/modelVersiongroupIdorg.qiu/groupIdartifactIdspring-003-dependency-injection/artifactIdversion1.0-SNAPSHOT/versionpropertiesmaven.compiler.source8/maven.compiler.sourcemaven.compiler.target8/maven.compiler.target/propertiesdependenciesdependencygroupIdorg.springframework/groupIdartifactIdspring-context/artifactIdversion5.3.23/version/dependencydependencygroupIdjunit/groupIdartifactIdjunit/artifactIdversion4.13.2/versionscopetest/scope/dependency!--log4j2的依赖--dependencygroupIdorg.apache.logging.log4j/groupIdartifactIdlog4j-core/artifactIdversion2.19.0/version/dependencydependencygroupIdorg.apache.logging.log4j/groupIdartifactIdlog4j-slf4j2-impl/artifactIdversion2.19.0/version/dependency/dependencies/project
package org.qiu.spring.dao;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.dao* date 2022-10-31-17:46* since 1.0*/
public class UserDao {private static final Logger logger LoggerFactory.getLogger(UserDao.class);public void insert(){logger.info(正在保存用户数据......);}
}package org.qiu.spring.service;import org.qiu.spring.dao.UserDao;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.service* date 2022-10-31-17:53* since 1.0*/
public class UserService {private UserDao userDao;// 使用set方式注入必须提供set方法。// 反射机制要调用这个方法给属性赋值的。public void setUserDao(UserDao userDao) {this.userDao userDao;}public void save(){userDao.insert();}
}
?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdbean iduserDaoBean classorg.qiu.spring.dao.UserDao/beanbean iduserServiceBean classorg.qiu.spring.service.UserService!--想让 Spring 调用对应的 set 方法需要配置 property 标签nameset方法的方法名去掉 set剩下的单词首字母变小写ref: references“引用”。指定要注入的 bean 的 id一般情况下 name 位置写属性名就行了--property nameuserDao refuserDaoBean/property/bean/beans
package org.qiu.spring.test;import org.junit.Test;
import org.qiu.spring.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.test* date 2022-10-31-17:55* since 1.0*/
public class DITest {Testpublic void testSetDI(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(spring.xml);UserService userService applicationContext.getBean(userServiceBean, UserService.class);userService.save();}
}
运行结果 原理解析 通过 property 标签获取到属性名userDao 通过属性名推断出 set 方法名setUserDao 通过反射机制调用 setUserDao() 方法给属性赋值 property 标签的 name 是属性名。 property 标签的 ref 是要注入的 bean 对象的 id。(通过ref属性来完成 bean 的装配这是 bean 最简单的一种装配方式。装配指的是创建系统组件之间关联的动作) 可以把 set 方法注释掉再测试一下 通过测试得知底层实际上调用了 setUserDao() 方法。所以需要确保这个方法的存在
另外对于 property 标签来说ref 属性也可以采用标签的方式但使用 ref 属性是多数的
bean iduserServiceBean classcom.powernode.spring6.service.UserServiceproperty nameuserDaoref beanuserDaoBean//property
/bean
总结set 注入的核心实现原理通过反射机制调用 set 方法来给属性赋值让两个对象之间产生关系 四、构造注入
核心原理通过调用构造方法来给属性赋值
package org.qiu.spring.service;import org.qiu.spring.dao.UserDao;
import org.qiu.spring.dao.VipDao;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.service* date 2022-11-01-20:25* since 1.0*/
public class CustomerService {private UserDao userDao;private VipDao vipDao;public CustomerService(UserDao userDao, VipDao vipDao) {this.userDao userDao;this.vipDao vipDao;}public void save(){userDao.insert();vipDao.insert();}
}
?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdbean iduserDaoBean classorg.qiu.spring.dao.UserDao/bean idvipDaoBean classorg.qiu.spring.dao.VipDao/bean idcsBean classorg.qiu.spring.service.CustomerService!--构造注入public CustomerService(UserDao userDao, VipDao vipDao) {this.userDao userDao;this.vipDao vipDao;}指定构造方法的第一个参数下标是 0--constructor-arg index0 refuserDaoBean/constructor-arg index1 refvipDaoBean//bean!-- 也可以使用 name 注入若不指定下标也不指定参数名Spring自动根据类型匹配注入 --bean idcsBean2 classorg.qiu.spring.service.CustomerServiceconstructor-arg nameuserDao refuserDaoBean/constructor-arg namevipDao refvipDaoBean//bean/beans
Test
public void testConstructDI(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(beans.xml);CustomerService service applicationContext.getBean(csBean,CustomerService.class);service.save();
}
运行结果 五、set 注入专题 注入外部 Bean
这种方式比较常用
!-- 声明/定义 bean --
bean idorderDaoBean classorg.qiu.spring.dao.OrderDao/bean idorderServiceBean classorg.qiu.spring.service.OrderService!-- 使用 ref 属性来引入就是注入外部 bean --property nameorderDao reforderDaoBean/
/bean 注入内部 Bean
这种方式使用较少了解即可。
bean idorderServiceBean2 classorg.qiu.spring.service.OrderServiceproperty nameorderDao!-- 内部 bean --bean classorg.qiu.spring.dao.OrderDao//property
/bean 注入简单类型
package org.qiu.spring.bean;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-06-07:14* since 1.0*/
public class User {private String username;private String password;private int age;Overridepublic String toString() {return User{ username username \ , password password \ , age age };}public void setUsername(String username) {this.username username;}public void setPassword(String password) {this.password password;}public void setAge(int age) {this.age age;}
}
!-- 注入简单类型 --
bean iduserBean classorg.qiu.spring.bean.Userproperty nameusername value张三/property namepassword value123/property nameage value20/
/bean Test
public void testSimpleTypeSet(){ApplicationContext application new ClassPathXmlApplicationContext(set-di.xml);User userBean application.getBean(userBean, User.class);System.out.println(userBean);
}
运行结果 分析简单类型包括哪些
Spring 源码BeanUtils 类
public class BeanUtils{//......./*** Check if the given type represents a simple property: a simple value* type or an array of simple value types.* pSee {link #isSimpleValueType(Class)} for the definition of emsimple* value type/em.* pUsed to determine properties to check for a simple dependency-check.* param type the type to check* return whether the given type represents a simple property* see org.springframework.beans.factory.support.RootBeanDefinition#DEPENDENCY_CHECK_SIMPLE* see org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#checkDependencies* see #isSimpleValueType(Class)*/public static boolean isSimpleProperty(Class? type) {Assert.notNull(type, type must not be null);return isSimpleValueType(type) || (type.isArray() isSimpleValueType(type.getComponentType()));}/*** Check if the given type represents a simple value type: a primitive or* primitive wrapper, an enum, a String or other CharSequence, a Number, a* Date, a Temporal, a URI, a URL, a Locale, or a Class.* p{code Void} and {code void} are not considered simple value types.* param type the type to check* return whether the given type represents a simple value type* see #isSimpleProperty(Class)*/public static boolean isSimpleValueType(Class? type) {return (Void.class ! type void.class ! type (ClassUtils.isPrimitiveOrWrapper(type) ||Enum.class.isAssignableFrom(type) ||CharSequence.class.isAssignableFrom(type) ||Number.class.isAssignableFrom(type) ||Date.class.isAssignableFrom(type) ||Temporal.class.isAssignableFrom(type) ||URI.class type ||URL.class type ||Locale.class type ||Class.class type));}//........
} 简单类型 基本数据类型 基本数据类型对应的包装类 String 或 其他的 CharSequence 子类 Number 子类 Date 子类 URI URL Temporal 子类Java8 新特性有关于时间时区的类 Locale Class 另外还包括以上简单值类型对应的数组类型 package org.qiu.spring.bean;import java.net.URI;
import java.net.URL;
import java.time.LocalDate;
import java.util.Date;
import java.util.Locale;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-06-07:37* since 1.0*/
public class SimpleValueType {public static void main(String[] args) {System.out.println(new Date());}private byte b;private short s;private int i;private long l;private float f;private double d;private boolean flag;private char c;private Byte b1;private Short s1;private Integer i1;private Long l1;private Float f1;private Double d1;private Boolean flag1;private Character c1;private String str;private Date date;private Season season;private URI uri;private URL url;private LocalDate localDate;private Locale locale;private Class clazz;// 省略 setter 和 toString
}enum Season {SPRING, SUMMER, AUTUMN, WINTER
}
?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexsi:schemaLocationhttp://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdbean idsimpleValueType classorg.qiu.spring.bean.SimpleValueTypeproperty nameb value1/property names value1/property namei value1/property namel value1/property namef value1/property named value1/property nameflag valuefalse/property namec valuea/property nameb1 value2/property names1 value2/property namei1 value2/property namel1 value2/property namef1 value2/property named1 value2/property nameflag1 valuetrue/property namec1 valuea/property namestr valuezhangsan/!--注意value后面的日期字符串格式不能随便写必须是Date对象toString()方法执行的结果。--!--如果想使用其他格式的日期字符串就需要进行特殊处理了--!--一般不会把 Date 当作简单类型而是使用 ref 给 Date 类型属性赋值--property namedate valueSun Nov 06 07:50:46 CST 2022/property nameseason valueWINTER/property nameuri value/save.do/!--spring6之后会自动检查url是否有效如果无效会报错。--property nameurl valuehttp://www.baidu.com/!--java.util.Locale 主要在软件的本地化时使用。它本身没有什么功能更多的是作为一个参数辅助其他方法完成输出的本地化。--property namelocale valueCHINESE/property nameclazz valuejava.lang.String//bean/beans
Test
public void testAllSimpleType(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(spring-all-simple-type.xml);SimpleValueType simpleValueType applicationContext.getBean(simpleValueType, SimpleValueType.class);System.out.println(simpleValueType);
}
运行结果 需要注意的是 如果把 Date 当做简单类型的话日期字符串格式不能随便写。格式必须符合 Date 的 toString() 方法格式。显然这就比较鸡肋了。如果我们提供一个这样的日期字符串2010-10-11在这里是无法赋值给 Date 类型的属性的。 Spring6 之后当注入的是 URL那么这个 url 字符串是会进行有效性检测的。如果是一个存在的 url那就没问题。如果不存在则报错。 级联属性赋值了解
package org.qiu.spring.bean;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-06-08:58* since 1.0*/
public class Clazz {private String name;public void setName(String name) {this.name name;}Overridepublic String toString() {return Clazz{ name name \ };}
}
package org.qiu.spring.bean;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-06-09:01* since 1.0*/
public class Student {private String name;public void setName(String name) {this.name name;}Overridepublic String toString() {return Student{ name name \ };}
}
bean idstudentBean classorg.qiu.spring.bean.Studentproperty namename value张三/
/beanbean idclazzBean classorg.qiu.spring.bean.Clazzproperty namename value高三一班/
/bean
Test
public void testCascade(){ApplicationContext application new ClassPathXmlApplicationContext(cascade.xml);Student studentBean application.getBean(studentBean, Student.class);System.out.println(studentBean);Clazz clazzBean application.getBean(clazzBean, Clazz.class);System.out.println(clazzBean);
}
运行结果 package org.qiu.spring.bean;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-06-09:01* since 1.0*/
public class Student {private String name;private Clazz clazz;public void setClazz(Clazz clazz) {this.clazz clazz;}public void setName(String name) {this.name name;}Overridepublic String toString() {return Student{ name name \ , clazz clazz };}
}
bean idstudentBean classorg.qiu.spring.bean.Studentproperty namename value张三/property nameclazz refclazzBean/
/bean
Test
public void testCascade(){ApplicationContext application new ClassPathXmlApplicationContext(cascade.xml);Student studentBean application.getBean(studentBean, Student.class);System.out.println(studentBean);Clazz clazzBean application.getBean(clazzBean, Clazz.class);System.out.println(clazzBean);
}
运行结果 !--级联属性赋值顺序不能颠倒使用级联属性赋值clazz 属性需要提供对应的 getter 方法
--
bean idstudentBean classorg.qiu.spring.bean.Studentproperty namename value张三/property nameclazz refclazzBean/property nameclazz.name value高三二班/
/beanbean idclazzBean classorg.qiu.spring.bean.Clazz/
public Clazz getClazz() {return clazz;
}
运行结果 注入数组
数组中的元素是简单类型
package org.qiu.spring.bean;import java.util.Arrays;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-06-22:16* since 1.0*/
public class QianDaYe {private String[] aiHaos;public void setAiHaos(String[] aiHaos) {this.aiHaos aiHaos;}Overridepublic String toString() {return QianDaYe{ aiHaos Arrays.toString(aiHaos) };}
}
bean idyuQian classorg.qiu.spring.bean.QianDaYe!-- 数组属性的元素是简单类型 --property nameaiHaosarrayvalue抽烟/valuevalue喝酒/valuevalue烫头/value/array/property
/bean
Test
public void testArray(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(spring-array.xml);QianDaYe yuQian applicationContext.getBean(yuQian, QianDaYe.class);System.out.println(yuQian);
}
运行结果 数组中元素不是简单类型
package org.qiu.spring.bean;import java.util.Arrays;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-06-22:16* since 1.0*/
public class QianDaYe {private String[] aiHaos;private Woman[] women;public void setAiHaos(String[] aiHaos) {this.aiHaos aiHaos;}public void setWomen(Woman[] women) {this.women women;}Overridepublic String toString() {return QianDaYe{ aiHaos Arrays.toString(aiHaos) , women Arrays.toString(women) };}
}
package org.qiu.spring.bean;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-06-22:24* since 1.0*/
public class Woman {private String name;public void setName(String name) {this.name name;}Overridepublic String toString() {return Woman{ name name \ };}
}
!-- 数组属性的元素不是简单类型 --
property namewomenarrayref beanw1 /ref beanw2 /ref beanw3 /ref beanw4 //array
/property
运行结果 注入 List 集合、Set 集合
注入集合集合中存放简单类型元素就用 value 标签存放的是非简单类型元素就用 ref 标签
package org.qiu.spring.bean;import java.util.List;
import java.util.Set;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-07-07:12* since 1.0*/
public class Person {// 注入 List 集合private ListString names;// 注入 Set 集合private SetString addrs;Overridepublic String toString() {return Person{ names names , addrs addrs };}public void setNames(ListString names) {this.names names;}public void setAddrs(SetString addrs) {this.addrs addrs;}
}
bean idpersonBean classorg.qiu.spring.bean.Personproperty namenames!-- List 集合有序可重复--listvalue张三/valuevalue张三/valuevalue张三/valuevalue李四/valuevalue李四/valuevalue王五/valuevalue王五/value/list/propertyproperty nameaddrs!-- Set 集合无序不可重复--setvalue北京/valuevalue广东/valuevalue上海/valuevalue上海/valuevalue上海/value/set/property
/bean Test
public void testCollection(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(spring-collection.xml);Person person applicationContext.getBean(personBean, Person.class);System.out.println(person);
}
运行结果 注入 Map 集合
// 注入 Map 集合
private MapInteger,String phones;Override
public String toString() {return Person{ names names , addrs addrs , phones phones };
}
property namephonesmap!-- key/value 都是简单类型使用 key/value --entry key1 value110/entry key3 value119/entry key5 value120/!-- key/value 不是简单类型使用 key-ref/value-ref --!-- entry key-ref value-ref / --/map
/property
运行结果 注入 Properties 属性类对象
/*** 注入属性类对象* Properties 本质上也是一个 Map 集合* Properties 的父类是 HashTableHashTable 实现了 Map 接口* 虽然也是一个 Map 集合但是注入方式相似但不同* Properties 的 key/value 只能是 String 类型*/
private Properties properties;public void setProperties(Properties properties) {this.properties properties;
}Override
public String toString() {return Person{ names names , addrs addrs , phones phones , properties properties };
}
property namepropertiespropsprop keydrivercom.nmysql.cj.jdbc.Driver/propprop keyurljdbc:mysql://localhost:3306/spring/propprop keyusernameroot/propprop keypassword123/prop/props
/property
运行结果 注入 null 和 空字符串
package org.qiu.spring.bean;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-07-07:42* since 1.0*/
public class Cat {private String name;private int age;Overridepublic String toString() {return Cat{ name name \ , age age };}public void setName(String name) {this.name name;}public void setAge(int age) {this.age age;}
}
bean idcatBean classorg.qiu.spring.bean.Cat!-- property namename value/property --!-- 手动注入 null --property namenamenull//propertyproperty nameage value3/property
/bean
Test
public void testNull(){ApplicationContext application new ClassPathXmlApplicationContext(set-di.xml);Cat cat application.getBean(catBean, Cat.class);System.out.println(cat);
}
运行结果 不给属性值注入默认就是 null也可以手动注入
bean idcatBean classorg.qiu.spring.bean.Cat!-- 注入 空字符串 --property namename value/property!-- 方式二 --!--property namenamevalue//property--property nameage value3/property
/bean
运行结果 注入特殊字符
XML中有5个特殊字符分别是、、、、
以上5个特殊符号在XML中会被特殊对待会被当做XML语法的一部分进行解析如果这些特殊符号直接出现在注入的字符串当中会报错。 解决方案包括两种 第一种特殊符号使用转义字符代替。 第二种将含有特殊符号的字符串放到![CDATA[]] 当中。因为放在 CDATA 区中的数据不会被 XML 文件解析器解析。
5个特殊字符对应的转义字符分别是
特殊字符转义字符gt;lt;apos;quot;amp; package org.qiu.spring.bean;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-07-07:58* since 1.0*/
public class Math {private String result;public void setResult(String result) {this.result result;}Overridepublic String toString() {return Math{ result result \ };}
}
!-- 方式一 --
bean idmathBean classorg.qiu.spring.bean.Mathproperty nameresult value2 lt; 3/
/bean
Test
public void testSpecial(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(set-di.xml);Math mathBean applicationContext.getBean(mathBean, Math.class);System.out.println(mathBean);
}
运行结果 使用 CDATA 方式
bean idmathBean classcom.powernode.spring6.beans.Mathproperty nameresult!--只能使用 value 标签--value![CDATA[2 3]]/value/property
/bean
注意使用CDATA时不能使用value属性只能使用value标签。
运行结果 六、p 命名空间注入
目的简化配置
使用 p 命名空间注入的前提条件包括两个 第一在 XML 头部信息中添加 p 命名空间的配置信息xmlns:phttp://www.springframework.org/schema/p 第二p 命名空间注入是基于 setter 方法的所以需要对应的属性提供 setter 方法
package org.qiu.spring.bean;import java.util.Date;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-07-08:10* since 1.0*/
public class Dog {private String name;private int age;private Date birth;Overridepublic String toString() {return Dog{ name name \ , age age , birth birth };}public void setName(String name) {this.name name;}public void setAge(int age) {this.age age;}public void setBirth(Date birth) {this.birth birth;}
}
?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:phttp://www.springframework.org/schema/pxsi:schemaLocationhttp://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd!--第一步在 Spring 配置文件头部添加 p 命名空间xmlns:phttp://www.springframework.org/schema/p第二步使用p:属性名 属性值简单类型p:属性名-ref 属性值非简单类型--bean iddogBean classorg.qiu.spring.bean.Dog p:name小花 p:age3 p:birth-refbirthBean/!-- 获取当前系统时间 --bean idbirthBean classjava.util.Date//beans
Test
public void testP(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(spring-p.xml);Dog dog applicationContext.getBean(dogBean, Dog.class);System.out.println(dog);
}
运行结果 七、C 命名空间注入
c 命名空间是简化构造方法注入的
使用 c 命名空间的两个前提条件
第一需要在 xml 配置文件头部添加信息xmlns:chttp://www.springframework.org/schema/c
第二需要提供构造方法
package org.qiu.spring.bean;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-07-21:34* since 1.0*/
public class People {private String name;private int age;private boolean sex;Overridepublic String toString() {return People{ name name \ , age age , sex sex };}public People(String name, int age, boolean sex) {this.name name;this.age age;this.sex sex;}
}
?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:chttp://www.springframework.org/schema/cxsi:schemaLocationhttp://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd!--第一步在 Spring 配置文件头部添加 xmlns:chttp://www.springframework.org/schema/c第二步使用可以使用属性名字或下标注入--bean idpeopleBean classorg.qiu.spring.bean.People c:_0张三 c:age18 c:sextrue/bean/beans
Test
public void testC(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(spring-c.xml);People people applicationContext.getBean(peopleBean, People.class);System.out.println(people);
}
运行结果 八、util 命名空间
util 命名空间让配置复用
使用util命名空间的前提是在spring配置文件头部添加配置信息。如下 package org.qiu.spring.bean;import java.util.Properties;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-07-21:34* since 1.0*/
public class MyDataSource1 {private Properties properties;public void setProperties(Properties properties) {this.properties properties;}Overridepublic String toString() {return MyDataSource1{ properties properties };}
}
package org.qiu.spring.bean;import java.util.Properties;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-07-21:34* since 1.0*/
public class MyDataSource2 {private Properties properties;public void setProperties(Properties properties) {this.properties properties;}Overridepublic String toString() {return MyDataSource2{ properties properties };}
}
?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:utilhttp://www.springframework.org/schema/utilxsi:schemaLocationhttp://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsdutil:properties idpropprop keydrivercom.mysql.cj.jdbc.Driver/propprop keyurljdbc:mysql://localhost:3306/spring/propprop keyusernameroot/propprop keypassword123456/prop/util:propertiesbean iddataSource1 classorg.qiu.spring.bean.MyDataSource1property nameproperties refprop//beanbean iddataSource2 classorg.qiu.spring.bean.MyDataSource2property nameproperties refprop//bean
/beans
Test
public void testUtil(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(spring-util.xml);MyDataSource1 dataSource1 applicationContext.getBean(dataSource1, MyDataSource1.class);System.out.println(dataSource1);MyDataSource2 dataSource2 applicationContext.getBean(dataSource2, MyDataSource2.class);System.out.println(dataSource2);
}
运行结果 九、基于 XML 自动装配
Spring 还可以完成自动化的注入自动化注入又被称为自动装配。它可以根据名字进行自动装配也可以根据类型进行自动装配 根据名称自动装配
package org.qiu.spring.dao;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.dao* date 2022-11-05-20:40* since 1.0*/
public class OrderDao {private static final Logger logger LoggerFactory.getLogger(OrderDao.class);public void generate(){logger.info(订单正在生成......);}
}
package org.qiu.spring.service;import org.qiu.spring.dao.OrderDao;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.service* date 2022-11-05-20:42* since 1.0*/
public class OrderService {private OrderDao orderDao;public void setOrderDao(OrderDao orderDao) {this.orderDao orderDao;}/*** 生成订单的业务方法*/public void generate(){orderDao.generate();}
}
!--id一般也叫做 bean 的名称根据名称自动装配这个 id 需要是 setter 方法的名字去掉 set再将首字母改为小写
--
bean idorderDao classorg.qiu.spring.dao.OrderDao/!--根据名字进行自动装配自动装配也是基于 set 注入实现的
--
bean idorderService classorg.qiu.spring.service.OrderService autowirebyName/bean
Test
public void testAutowire(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(spring-autowire.xml);OrderService orderService applicationContext.getBean(orderService, OrderService.class);orderService.generate();
}
运行结果 根据类型自动装配
package org.qiu.spring.dao;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.dao* date 2022-10-31-20:27* since 1.0*/
public class VipDao {private static final Logger logger LoggerFactory.getLogger(UserDao.class);public void insert(){logger.info(正在保存VIP信息......);}
}
package org.qiu.spring.dao;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.dao* date 2022-10-31-17:46* since 1.0*/
public class UserDao {private static final Logger logger LoggerFactory.getLogger(UserDao.class);public void insert(){logger.info(正在保存用户数据......);}
}
package org.qiu.spring.service;import org.qiu.spring.dao.UserDao;
import org.qiu.spring.dao.VipDao;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.service* date 2022-11-01-20:25* since 1.0*/
public class CustomerService {private UserDao userDao;private VipDao vipDao;public void setUserDao(UserDao userDao) {this.userDao userDao;}public void setVipDao(VipDao vipDao) {this.vipDao vipDao;}/*public CustomerService(UserDao userDao, VipDao vipDao) {this.userDao userDao;this.vipDao vipDao;}*/public void save(){userDao.insert();vipDao.insert();}
}
!--根据类型注入自动装配是基于 setter 方法的必须提供 setter 方法根据类型进行自动装配的时候在有效的配置文件当中某种类型的实例只能有一个
--
bean classorg.qiu.spring.dao.VipDao/
bean classorg.qiu.spring.dao.UserDao/
bean idcs classorg.qiu.spring.service.CustomerService autowirebyType/
Test
public void testAutowireByType(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(spring-autowire.xml);CustomerService customerService applicationContext.getBean(cs, CustomerService.class);customerService.save();
}
运行结果 十、Spring 引入外部属性配置文件
我们都知道编写数据源的时候是需要连接数据库的信息的例如driver url username password等信息。这些信息可以单独写到一个属性配置文件中这样用户修改起来会更加的方便
第一步写一个数据源类提供相关属性
package org.qiu.spring.bean;import javax.sql.DataSource;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.util.logging.Logger;/*** author 秋玄* version 1.0* email qiu_2022aliyun.com* project Spring* package org.qiu.spring.bean* date 2022-11-09-11:01* since 1.0*/
public class MyDataSource implements DataSource {private String driver;private String url;private String username;private String password;Overridepublic String toString() {return MyDataSource{ driver driver \ , url url \ , username username \ , password password \ };}public String getDriver() {return driver;}public void setDriver(String driver) {this.driver driver;}public String getUrl() {return url;}public void setUrl(String url) {this.url url;}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;}// 省略实现 DataSource 接口中的方法
}
第二步在类路径下新建 jdbc.properties 文件并配置信息
drivercom.mysql.cj.jdbc.Driver
urljdbc:mysql://localhost:3306/spring
usernameroot
passwordroot
第三步在 spring 配置文件中引入 context 命名空间
?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contexthttp://www.springframework.org/schema/contextxsi:schemaLocationhttp://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd/beans
第四步在 spring 中配置使用 jdbc.properties 文件
?xml version1.0 encodingUTF-8?
beans xmlnshttp://www.springframework.org/schema/beansxmlns:xsihttp://www.w3.org/2001/XMLSchema-instancexmlns:contexthttp://www.springframework.org/schema/contextxsi:schemaLocationhttp://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context.xsdcontext:property-placeholder locationjdbc.properties/bean iddataSource classorg.qiu.spring.bean.MyDataSourceproperty namedriver value${driver}/property nameurl value${url}/property nameusername value${username}/property namepassword value${password}//bean/beans
测试程序
Test
public void testProperties(){ApplicationContext applicationContext new ClassPathXmlApplicationContext(spring-properties.xml);MyDataSource dataSource applicationContext.getBean(dataSource, MyDataSource.class);System.out.println(dataSource);
}
运行结果 一 叶 知 秋奥 妙 玄 心
