Spring_初识配置+DI
第一个spring程序配置流程
先导入依赖
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.3.24</version>
</dependency>
实体类
public class Hello {
private String str;
public String getStr() {
return str;
}
public void setStr(String str) {
this.str = str;
}
@Override
public String toString() {
return "Hello{" +
"str='" + str + '\'' +
'}';
}
}
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"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd">
<!-- 使用Spring来创建对象，在Spring中，这些都称为Bean
类型 变量名 = new 类型()
Hello hello =new Hello()
bean = 对象 new hello();
id=变量名
class=new 对象
property 相当于给对象中属性赋值
-->
<bean id="hello" class="com.xiaofan.pojo.Hello">
<property name="str" value="Spring"/>
</bean>
</beans>
public class MyTest {
@Test
public void test(){
//获取spring的上下文对象
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
//我们的对象现在都在spring中的管理了，我们要使用，直接去里面取出来就可以
Hello hello = (Hello) context.getBean("hello");
System.out.println(hello.toString());
}
}
构造器注入
实体类
package com.xiaofan.pojo;
public class User {
private String name;
public User(){
System.out.println("User的无参构造");
}
public User(String name){
this.name =name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public void show(){
System.out.println("name:"+name);
}
}
<?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
https://www.springframework.org/schema/beans/spring-beans.xsd">
<!-- 第一种，下标赋值-->
<!-- <bean id="user" class="com.xiaofan.pojo.User">-->
<!-- <constructor-arg index="0" value="小凡"/>-->
<!-- </bean>-->
<!-- 不建议使用，如果两个参数都是String?-->
<!-- <bean id="user" class="com.xiaofan.pojo.User">-->
<!-- <constructor-arg type="java.lang.String" value="xiaofan"/>-->
<!-- </bean>-->
<!-- 直接通过参数名来设置-->
<bean id="user" class="com.xiaofan.pojo.User">
<constructor-arg name="name" value="xiaofan"/>
</bean>
</beans>
public class MyTest {
public static void main(String[] args) {
ApplicationContext context =new ClassPathXmlApplicationContext("beans.xml");
User user = (User) context.getBean("user");
user.show();
}
}
DI(依赖注入)
实体类
public class Student {
private String name;
private Address address;
private String[] books;
private List<String> hobbies;
private Map<String ,String > card;
private Set<String> games;
private Properties info;
private String wife;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Address getAddress() {
return address;
}
public void setAddress(Address address) {
this.address = address;
}
public String[] getBooks() {
return books;
}
public void setBooks(String[] books) {
this.books = books;
}
public List<String> getHobbies() {
return hobbies;
}
public void setHobbies(List<String> hobbies) {
this.hobbies = hobbies;
}
public Map<String, String> getCard() {
return card;
}
public void setCard(Map<String, String> card) {
this.card = card;
}
public Set<String> getGames() {
return games;
}
public void setGames(Set<String> games) {
this.games = games;
}
public Properties getInfo() {
return info;
}
public void setInfo(Properties info) {
this.info = info;
}
public String getWife() {
return wife;
}
public void setWife(String wife) {
this.wife = wife;
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", address=" + address.toString() +
", books=" + Arrays.toString(books) +
", hobbies=" + hobbies +
", card=" + card +
", games=" + games +
", info=" + info +
", wife='" + wife + '\'' +
'}';
}
}
public class Address {
private String address;
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "Address{" +
"address='" + address + '\'' +
'}';
}
}
<?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
https://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="address" class="com.xiaofan.pojo.Address">
<property name="address" value="西安"/>
</bean>
<bean id="student" class="com.xiaofan.pojo.Student">
<!-- 第一种，普通值注入，value-->
<property name="name" value="小凡"/>
<!-- 第二种，bean注入，ref-->
<property name="address" ref="address"/>
<!-- 数组注入-->
<property name="books">
<array>
<value>西游记</value>
<value>三国演义</value>
<value>水浒传</value>
<value>红楼梦</value>
</array>
</property>
<!-- list注入-->
<property name="hobbies">
<list>
<value>听歌</value>
<value>敲代码</value>
<value>看电影</value>
</list>
</property>
<!-- map注入-->
<property name="card">
<map>
<entry key="身份证" value="1234567898765433456"/>
<entry key="银行卡" value="3245678987654345765"/>
</map>
</property>
<!-- set注入-->
<property name="games">
<set>
<value>王者荣耀</value>
<value>LOL</value>
</set>
</property>
<!-- null注入-->
<property name="wife">
<null/>
</property>
<!-- Properties注入，特殊类型-->
<property name="info">
<props>
<prop key="driver">com.mysql.jdbc.Driver</prop>
<prop key="url">jdbc:mysql://localhost:8080/spring</prop>
<prop key="username">xiaofan</prop>
<prop key="password">123456</prop>
</props>
</property>
</bean>
</beans>
@Test
public void test(){
ApplicationContext context =new ClassPathXmlApplicationContext("beans.xml");
Student student =(Student) context.getBean("student");
System.out.println(student.toString());
}
命名空间注入
实体类
public class User {
private String name;
private int age;
public User() {
}
public User(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "User{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}
<?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:p="http://www.springframework.org/schema/p"
xmlns:c="http://www.springframework.org/schema/c"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd">
<!-- p命名空间注入，可以直接注入属性的值：property-->
<bean id="user" class="com.xiaofan.pojo.User" p:name="小凡" p:age="18"/>
<!-- c命名空间注入,通过构造器注入：construct-args-->
<bean id="user2" class="com.xiaofan.pojo.User" c:age="19" c:name="tata"/>
</beans>
@Test
public void test2(){
ApplicationContext context =new ClassPathXmlApplicationContext("userbeans.xml");
User user = context.getBean("user2", User.class);
System.out.println(user);
}
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