Spring注入值到Bean的三种方式

package com.example.pojo;

public class User
{
 private String username;
 private String password;
 
 public String getUsername() {
 return username;
 }
 public void setUsername(String username) {
 this.username= username;
 }
 public String getPassword() {
 return type;
 }
 public void setPassword(String password) {
 this.password= password;
 }
}

<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
 http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

 <bean id="user" class="com.example.User">
 <property name="username">
  <value>scott</value>
 </property>
 <property name="password">
  <value>tiger</value>
 </property>
 </bean>
</beans>

<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
 http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

 <bean id="user" class="com.example.User">
 <property name="username" value="scott" />
 <property name="password" value="tiger" />
 </bean>
</beans>

<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"
 xsi:schemaLocation="http://www.springframework.org/schema/beans
 http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

 <bean id="user" class="com.example.User" 
  p:username="scott" p:password="tiger" />
 
</beans>