Spring - Bean属性注入
依赖注入的三种方式
1. 构造器注入
class UserService {
private UserDao userDao;
public UserService(UserDao userDao){
this.userDao = userDao;
}
}
2. setter注入
class Uservice {
private UserDao userDao;
public void setUserDao(UserDao userDao){
this.userDao = userDao;
}
3. 感知接口注入
interface UserDaoAware {
public void injectUserDao(UserDao userDao);
}
class UserService implements UserDaoAware {
private UserDao userDao;
public void injectUserDao(UserDao userDao){
this.userDao = userDao;
}
}
Spring支持前两种方式
Employee
package main.com.lee.e_di;
/**
* 雇员
*
* @author Lynch
*
*/
public class Employee {
private Integer age;
private String name;
private Product product;
public void setProduct(Product product) {
this.product = product;
}
public void setAge(Integer age) {
this.age = age;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Employee [age=" + age + ", name=" + name + ", product=" + product + "]";
}
}
EmployeeInfo
package main.com.lee.e_di;
/**
* 数据bean
*
* @author Lynch
*
*/
public class EmployeeInfo {
private String name = "周通";
private Integer age = 23;
public String getName() {
return name;
}
public Integer peekAge() {
return age;
}
}
Product
package main.com.lee.e_di;
/**
* 商品
*/
public class Product {
private String name;
private Double price;
public Product(String name, Double price) {
this.name = name;
this.price = price;
}
@Override
public String toString() {
return "Product [name=" + name + ", price=" + price + "]";
}
}
Student
package main.com.lee.e_di;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
public class Student {
private String[] aArr;
private List<String> aList;
private Set<String> aSet;
private Map<String, String> aMap;
private Properties properties;
public void setProperties(Properties properties) {
this.properties = properties;
}
public void setaArr(String[] aArr) {
this.aArr = aArr;
}
public void setaList(List<String> aList) {
this.aList = aList;
}
public void setaSet(Set<String> aSet) {
this.aSet = aSet;
}
public void setaMap(Map<String, String> aMap) {
this.aMap = aMap;
}
@Override
public String toString() {
return "Student [aArr=" + Arrays.toString(aArr) + ", aList=" + aList + ", aSet=" + aSet + ", aMap=" + aMap + ", properties=" + properties
+ "]";
}
}
applicationCotext.xml
<!-- 依赖注入的方式 构造器注入 -->
<bean id="product" class="main.com.lee.e_di.Product">
<constructor-arg index="0" type="java.lang.String"
value="宝马" />
<constructor-arg index="1" type="java.lang.Double"
value="1111.1" />
</bean>
<!-- 依赖注入的方式 setter方式 -->
<bean id="employee" class="main.com.lee.e_di.Employee">
<property name="age" value="23" />
<property name="name" value="成龙" />
<property name="product" ref="product" />
</bean>
<!-- P名称空间注入 -->
<bean id="employee2" class="main.com.lee.e_di.Employee" p:name="李连杰"
p:age="44" p:product-ref="product" />
<!-- SpEL -->
<bean id="employeeInfo" class="main.com.lee.e_di.EmployeeInfo" />
<bean id="employee3" class="main.com.lee.e_di.Employee">
<property name="name" value="#{employeeInfo.name}"></property>
<property name="age" value="#{employeeInfo.peekAge()}"></property>
<property name="product" value="#{product}"></property>
</bean>
<!-- 集合属性的注入 -->
<bean id="student" class="main.com.lee.e_di.Student">
<property name="aArr">
<list>
<value>数组值1</value>
<value>数组值2</value>
</list>
</property>
<property name="aList">
<list>
<value>列表值1</value>
<value>列表值2</value>
</list>
</property>
<property name="aSet">
<set>
<value>集合值1</value>
<value>集合值2</value>
<value>集合值2</value>
</set>
</property>
<property name="aMap">
<map>
<entry key="key1" value="映射值1"></entry>
<entry>
<key>
<value>key2</value>
</key>
<value>映射值2</value>
</entry>
</map>
</property>
<property name="properties">
<props>
<prop key="key1">值1</prop>
<prop key="key2">值2</prop>
</props>
</property>
</bean>
Test
package main.com.lee.e_di;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
* 依赖注入方式小测
*
* @author Lynch
*
*/
public class BeanDITest {
@Test
public void demo1() {
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");
// 构造器注入
Product product = (Product) applicationContext.getBean("product");
System.out.println(product);
// setter注入
Employee employee = (Employee) applicationContext.getBean("employee");
System.out.println(employee);
// p名称空间注入
Employee employee2 = (Employee) applicationContext.getBean("employee2");
System.out.println(employee2);
// SpEL注入
Employee employee3 = (Employee) applicationContext.getBean("employee3");
System.out.println(employee3);
// 集合注入
Student student = (Student) applicationContext.getBean("student");
System.out.println(student);
}
}
out
Product [name=宝马, price=1111.1]
Employee [age=23, name=成龙, product=Product [name=宝马, price=1111.1]]
Employee [age=44, name=李连杰, product=Product [name=宝马, price=1111.1]]
Employee [age=23, name=周通, product=Product [name=宝马, price=1111.1]]
Student [aArr=[数组值1, 数组值2], aList=[列表值1, 列表值2], aSet=[集合值1, 集合值2], aMap={key1=映射值1, key2=映射值2}, properties={key2=值2, key1=值1}]