UserService
public interface UserService {
public void save();
}
UserServiceImpl
public class UserServiceImpl implements UserService {
@Override
public void save() {
ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
UserDao userDao = (UserDao) app.getBean("userDao");
userDao.save();
}
}
<bean id="userDao" class="com.xdr630.dao.impl.UserDaoImpl"></bean>
<bean id="userService" class="com.xdr630.service.Impl.UserServiceImpl"></bean>
public class UserController {
public static void main(String[] args) {
ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService userService = (UserService) app.getBean("userService");
userService.save();
}
}
怎么将UserDao怎样注入到UserService内部呢?
1)set方法注入
在UserServiceImpl中添加setUserDao方法
public class UserServiceImpl implements UserService {
private UserDao userDao;
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
@Override
public void save() {
userDao.save();
}
}
配置Spring容器调用set方法进行注入
<bean id="userDao" class="com.xdr630.dao.impl.UserDaoImpl"></bean>
<bean id="userService" class="com.xdr630.service.Impl.UserServiceImpl">
<property name="userDao" ref="userDao"></property>
</bean>
1)set方法注入
P命名空间注入本质也是set方法注入,但比起上述的set方法注入更加方便,主要体现在配置文件中,如下:
首先,需要引入P命名空间:
xmlns:p="http://www.springframework.org/schema/p"
其次,需要修改注入方式
<bean id="userService" class="com.xdr630.service.Impl.UserServiceImpl" p:userDao-ref="userDao"/>
2)构造方法注入
创建有参构造
public class UserServiceImpl implements UserService {
private UserDao userDao;
public UserServiceImpl() {
}
public UserServiceImpl(UserDao userDao) {
this.userDao = userDao;
}
@Override
public void save() {
userDao.save();
}
}
<bean id="userDao" class="com.xdr630.dao.impl.UserDaoImpl"></bean>
<bean id="userService" class="com.xdr630.service.Impl.UserServiceImpl">
<constructor-arg name="userDao" ref="userDao"></constructor-arg>
</bean>
public class UserDaoImpl implements UserDao {
private String username;
private int age;
public void setUsername(String username) {
this.username = username;
}
public void setAge(int age) {
this.age = age;
}
@Override
public void save() {
System.out.println("username=" + username + "\n" + "age=" + age);
System.out.println("save running......");
}
}
<bean id="userDao" class="com.xdr630.dao.impl.UserDaoImpl">
<property name="username" value="xdr"/>
<property name="age" value="22"/>
</bean>
List <String>
)的注入public interface UserDao {
public void save();
}
public class UserDaoImpl implements UserDao {
private List<String> strList;
public void setStrList(List<String> strList) {
this.strList = strList;
}
public void save() {
System.out.println(strList);
System.out.println("save running......");
}
public interface UserService {
public void save();
}
public class UserServiceImpl implements UserService {
private UserDao userDao;
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
public UserServiceImpl() {
}
public UserServiceImpl(UserDao userDao) {
this.userDao = userDao;
}
@Override
public void save() {
userDao.save();
}
}
List<String>
是普通数据类型,用 value,如果是 User 或其他对象用 ref<bean id="userDao" class="com.xdr630.dao.impl.UserDaoImpl">
<property name="strList">
<list>
<value>aaa</value>
<value>bbb</value>
<value>ccc</value>
</list>
</property>
</bean>
<bean id="userService" class="com.xdr630.service.Impl.UserServiceImpl">
<constructor-arg name="userDao" ref="userDao"></constructor-arg>
</bean>
public class UserController {
public static void main(String[] args) {
ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService userService = (UserService) app.getBean("userService");
userService.save();
}
}
Map<String User>
)的注入public class User {
private String name;
private String addr;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddr() {
return addr;
}
public void setAddr(String addr) {
this.addr = addr;
}
@Override
public String toString() {
return "User{" +
"name='" + name + '\'' +
", addr='" + addr + '\'' +
'}';
}
}
public class UserDaoImpl implements UserDao {
private List<User> userList;
public void setUserList(List<User> userList) {
this.userList = userList;
}
public void save() {
System.out.println(userList);
System.out.println("save running......");
}
}
<bean id="userDao" class="com.xdr630.dao.impl.UserDaoImpl">
<property name="userMap">
<map>
<entry key="u1" value-ref="user1"></entry>
<entry key="u2" value-ref="user2"></entry>
</map>
</property>
</bean>
<bean id="user1" class="com.xdr630.domain.User">
<property name="name" value="tom"/>
<property name="addr" value="beijing"/>
</bean>
<bean id="user2" class="com.xdr630.domain.User">
<property name="name" value="jerry"/>
<property name="addr" value="shanghai"/>
</bean>
<bean id="userService" class="com.xdr630.service.Impl.UserServiceImpl">
<constructor-arg name="userDao" ref="userDao"></constructor-arg>
</bean>
public class UserController {
public static void main(String[] args) {
ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService userService = (UserService) app.getBean("userService");
userService.save();
}
}
<bean id="userDao" class="com.xdr630.dao.impl.UserDaoImpl">
<property name="properties">
<props>
<prop key="p1">ppp1</prop>
<prop key="p2">ppp2</prop>
<prop key="p3">ppp3</prop>
</props>
</property>
</bean>
<bean id="userService" class="com.xdr630.service.Impl.UserServiceImpl">
<constructor-arg name="userDao" ref="userDao"></constructor-arg>
</bean>
public class UserDaoImpl implements UserDao {
private Properties properties;
public void setProperties(Properties properties) {
this.properties = properties;
}
public void save() {
System.out.println(properties);
System.out.println("save running......");
}
}
public class UserController {
public static void main(String[] args) {
ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService userService = (UserService) app.getBean("userService");
userService.save();
}
}
<import resource="applicationContext-xxx.xml"/>
<bean>标签
id属性:在容器中Bean实例的唯一标识,不允许重复
class属性:要实例化的Bean的全限定名
scope属性:Bean的作用范围,常用是Singleton(默认)和prototype
<property>标签:属性注入
name属性:属性名称
value属性:注入的普通属性值
ref属性:注入的对象引用值
<list>标签
<map>标签
<properties>标签
<constructor-arg>标签
<import>标签:导入其他的Spring的分文件
原创声明:本文系作者授权腾讯云开发者社区发表,未经许可,不得转载。
如有侵权,请联系 cloudcommunity@tencent.com 删除。
原创声明:本文系作者授权腾讯云开发者社区发表,未经许可,不得转载。
如有侵权,请联系 cloudcommunity@tencent.com 删除。