package com.yl.bean;

public class DataSource {
  private String url;
  private String username;
  private String password;

  public DataSource() {
  }

  public String getUrl() {
    return url;
  }

  public void setUrl(String url) {
    this.url = url;
  }

  public String getUsername() {
    return username;
  }

  public void setUsername(String username) {
    this.username = username;
  }

  public String getPassword() {
    return password;
  }

  public void setPassword(String password) {
    this.password = password;
  }

  @Override
  public String toString() {
    return "DataSource{" +
        "url='" + url + '\'' +
        ", username='" + username + '\'' +
        ", password='" + password + '\'' +
        '}';
  }
}

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

  <!--導(dǎo)入配置文件-->
  <context:property-placeholder location="classpath:db.properties"></context:property-placeholder>

  <!--DataSource-->
  <bean id="dataSource" class="com.yl.bean.DataSource">
    <property name="password" value="${password}"></property>
    <property name="username" value="${username}"></property>
    <property name="url" value="${url}"></property>
  </bean>

</beans>

package com.yl;

import com.yl.bean.DataSource;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MainTest {

  public static void main(String[] args) {
    ApplicationContext applicationContext=new ClassPathXmlApplicationContext("bean1.xml");

    DataSource dataSource= (DataSource) applicationContext.getBean("dataSource");

    System.out.println(dataSource);
  }
}