spring appicationContext.xml
spring在加载applicationContext.xml文件的时候就把对象创建出来了,xml中配置的各种对象的创建方式就会被调用一遍不管你有没有从spring容器中申请对象,都会输出构造函数中的打印语句。
共用实体类
User.java
package cn.itcast.bean; public class User { public User() { System.out.println("User对象空参构造方法!!!!"); }
private String name; private Integer age; private Car car; public User(String name, Car car) { System.out.println("User(String name, Car car)!!"); this.name = name; this.car = car; } public User(Car car,String name) { System.out.println("User(Car car,String name)!!"); this.name = name; this.car = car; } public User(Integer name, Car car) { System.out.println("User(Integer name, Car car)!!"); this.name = name+""; this.car = car; } public Car getCar() { return car; } public void setCar(Car car) { this.car = car; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public void init(){ System.out.println("我是初始化方法!"); } public void destory(){ System.out.println("我是销毁方法!"); }
@Override public String toString() { return "User [name=" + name + ", age=" + age + ", car=" + car + "]"; } }
Car.java
package cn.itcast.bean; public class Car { private String name; private String color; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getColor() { return color; } public void setColor(String color) { this.color = color; } @Override public String toString() { return "Car [name=" + name + ", color=" + color + "]"; } }
1、普通配置
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd "> <!-- 将User对象交给spring容器管理 --> <!-- Bean元素:使用该元素描述需要spring容器管理的对象 class属性:被管理对象的完整类名. name属性:给被管理的对象起个名字.获得对象时根据该名称获得对象. 可以重复.可以使用特殊字符. id属性: 与name属性一模一样. 名称不可重复.不能使用特殊字符. 结论: 尽量使用name属性. --> <bean name="user" class="cn.itcast.bean.User" ></bean> <!-- 导入其他spring配置文件 --> <import resource="cn/itcast/b_create/applicationContext.xml"/> </beans>
测试:
public class Demo { @Test public void fun1(){ //1 创建容器对象 ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml"); //2 向容器"要"user对象 User u = (User) ac.getBean("user"); //3 打印user对象 System.out.println(u); } }
2、创建方式配置
UserFactory.java
public class UserFactory { public static User createUser(){ System.out.println("静态工厂创建User"); return new User(); } public User createUser2(){ System.out.println("实例工厂创建User"); return new User(); } }
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd "> <!-- 创建方式1:空参构造创建 --> <bean name="user" class="cn.itcast.bean.User" init-method="init" destroy-method="destory" ></bean>
<!-- 创建方式2:静态工厂创建 调用UserFactory的createUser方法创建名为user2的对象.放入容器 --> <bean name="user2" class="cn.itcast.b_create.UserFactory" factory-method="createUser" ></bean>
<!-- 创建方式3:实例工厂创建 调用UserFactory对象的createUser2方法创建名为user3的对象.放入容器 --> <bean name="user3" factory-bean="userFactory" factory-method="createUser2" ></bean> <bean name="userFactory" class="cn.itcast.b_create.UserFactory" ></bean> </beans>
测试:
@Test // 创建方式1:空参构造 public void fun1() { // 1 创建容器对象 ApplicationContext ac = new ClassPathXmlApplicationContext( "cn/itcast/b_create/applicationContext.xml"); // 2 向容器"要"user对象 User u = (User) ac.getBean("user"); // 3 打印user对象 System.out.println(u); } // 创建方式2:静态工厂 @Test public void fun2() { // 1 创建容器对象 ApplicationContext ac = new ClassPathXmlApplicationContext( "cn/itcast/b_create/applicationContext.xml"); // 2 向容器"要"user对象 User u = (User) ac.getBean("user2"); // 3 打印user对象 System.out.println(u); } // 创建方式3:实例工厂 @Test public void fun3() { // 1 创建容器对象 ApplicationContext ac = new ClassPathXmlApplicationContext( "cn/itcast/b_create/applicationContext.xml"); // 2 向容器"要"user对象 User u = (User) ac.getBean("user3"); // 3 打印user对象 System.out.println(u); } @Test // scope:singleton 单例 // scope:prototype 多例 public void fun4() { // 1 创建容器对象 ApplicationContext ac = new ClassPathXmlApplicationContext( "cn/itcast/b_create/applicationContext.xml"); // 2 向容器"要"user对象 User u = (User) ac.getBean("user"); User u2 = (User) ac.getBean("user"); User u3 = (User) ac.getBean("user"); User u4 = (User) ac.getBean("user"); System.out.println(u2 == u4);// 单例:true // 多例:false // 3 打印user对象 System.out.println(u); } @Test // 测试生命周期方法 public void fun5() { // 1 创建容器对象 ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext( "cn/itcast/b_create/applicationContext.xml"); // 2 向容器"要"user对象 User u = (User) ac.getBean("user"); // 3 打印user对象 System.out.println(u); // 关闭容器,触发销毁方法 ac.close(); }
当你运行第一个测试方法的时候控制台就会输出以下东西(因为spring加载配置文件的时候会把配置文件下所有的对象都创建)
User对象空参构造方法!!!! 我是初始化方法! 静态工厂创建User User对象空参构造方法!!!! 实例工厂创建User User对象空参构造方法!!!! User [name=null, age=null, car=null]
3、注入方式配置
CollectionBean.java
public class CollectionBean { private Object[] arr;//数组类型注入 private List list;//list/set 类型注入 private Map map;//map类型注入 private Properties prop;//properties类型注入 public Object[] getArr() { return arr; } public void setArr(Object[] arr) { this.arr = arr; } public List getList() { return list; } public void setList(List list) { this.list = list; } public Map getMap() { return map; } public void setMap(Map map) { this.map = map; } public Properties getProp() { return prop; } public void setProp(Properties prop) { this.prop = prop; } @Override public String toString() { return "CollectionBean [arr=" + Arrays.toString(arr) + ", list=" + list + ", map=" + map + ", prop=" + prop + "]"; } }
配置:
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xmlns:p="http://www.springframework.org/schema/p" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd "> <!-- set方式注入: --> <bean name="user" class="cn.itcast.bean.User" > <!--值类型注入: 为User对象中名为name的属性注入tom作为值 --> <property name="name" value="tom" ></property> <property name="age" value="18" ></property> <!-- 引用类型注入: 为car属性注入下方配置的car对象 --> <property name="car" ref="car" ></property> </bean> <!-- 将car对象配置到容器中 --> <bean name="car" class="cn.itcast.bean.Car" > <property name="name" value="兰博基尼" ></property> <property name="color" value="黄色" ></property> </bean> <!-- ============================================================ --> <!-- 构造函数注入 --> <bean name="user2" class="cn.itcast.bean.User" > <!-- name属性: 构造函数的参数名 --> <!-- index属性: 构造函数的参数索引 --> <!-- type属性: 构造函数的参数类型--> <!-- 上面 index和type是为了区分哪个构造函数 --> <constructor-arg name="name" index="0" type="java.lang.Integer" value="999" ></constructor-arg> <constructor-arg name="car" ref="car" index="1" ></constructor-arg> </bean> <!-- ============================================================= --> <!-- p名称空间注入, 走set方法 1.导入P名称空间 xmlns:p="http://www.springframework.org/schema/p" 2.使用p:属性完成注入 |-值类型: p:属性名="值" |-对象类型: p:属性名-ref="bean名称" --> <bean name="user3" class="cn.itcast.bean.User" p:name="jack" p:age="20" p:car-ref="car" > </bean> <!-- ============================================================= --> <!--spel注入: spring Expression Language sping表达式语言--> <bean name="user4" class="cn.itcast.bean.User" > <property name="name" value="#{user.name}" ></property> <property name="age" value="#{user3.age}" ></property> <property name="car" ref="car" ></property> </bean> <!-- ============================================================= --> <!-- 复杂类型注入 --> <bean name="cb" class="cn.itcast.c_injection.CollectionBean" > <!-- 如果数组中只准备注入一个值(对象),直接使用value|ref即可 <property name="arr" value="tom" ></property> --> <!-- array注入,多个元素注入 --> <property name="arr"> <array> <value>tom</value> <value>jerry</value> <ref bean="user4" /> </array> </property> <!-- 如果List中只准备注入一个值(对象),直接使用value|ref即可 <property name="list" value="jack" ></property> --> <property name="list" > <list> <value>jack</value> <value>rose</value> <ref bean="user3" /> </list> </property> <!-- map类型注入 --> <property name="map" > <map> <entry key="url" value="jdbc:mysql:///crm" ></entry> <entry key="user" value-ref="user4" ></entry> <entry key-ref="user3" value-ref="user2" ></entry> </map> </property> <!-- prperties 类型注入 --> <property name="prop" > <props> <prop key="driverClass">com.jdbc.mysql.Driver</prop> <prop key="userName">root</prop> <prop key="password">1234</prop> </props> </property> </bean> </beans>
测试:
public class Demo { @Test public void fun1(){ //1 创建容器对象 ApplicationContext ac = new ClassPathXmlApplicationContext("cn/itcast/c_injection/applicationContext.xml"); //2 向容器"要"user对象 User u = (User) ac.getBean("user"); //3 打印user对象 System.out.println(u); } @Test public void fun2(){ //1 创建容器对象 ApplicationContext ac = new ClassPathXmlApplicationContext("cn/itcast/c_injection/applicationContext.xml"); //2 向容器"要"user对象 User u = (User) ac.getBean("user2"); //3 打印user对象 System.out.println(u); } @Test public void fun3(){ //1 创建容器对象 ApplicationContext ac = new ClassPathXmlApplicationContext("cn/itcast/c_injection/applicationContext.xml"); //2 向容器"要"user对象 User u = (User) ac.getBean("user3"); //3 打印user对象 System.out.println(u); } @Test public void fun4(){ //1 创建容器对象 ApplicationContext ac = new ClassPathXmlApplicationContext("cn/itcast/c_injection/applicationContext.xml"); //2 向容器"要"user对象 User u = (User) ac.getBean("user4"); //3 打印user对象 System.out.println(u); } @Test public void fun5(){ //1 创建容器对象 ApplicationContext ac = new ClassPathXmlApplicationContext("cn/itcast/c_injection/applicationContext.xml"); //2 向容器"要"user对象 CollectionBean cb = (CollectionBean) ac.getBean("cb"); //3 打印user对象 System.out.println(cb); } }
测试结果:
User对象空参构造方法!!!! User(Integer name, Car car)!! User对象空参构造方法!!!! User对象空参构造方法!!!! User [name=tom, age=18, car=Car [name=兰博基尼, color=黄色]]