spring mvc 读取xml文件数据库配置参数的方法

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本文主要介绍怎么通过属性注入与构造器注入实现把我们项目中要用到的数据库参数放到xml文件里面去，方便部署。

spring mvc 4.2.6项目

SQL Server 2008数据库

本文介绍的主要使用ApplicationContext以及其实现类实现。主要用到的是ClassPathXmlApplicationContext。

ClassPathXmlApplicationContext：从类路径ClassPath中寻找指定的XML配置文件，找到并装载

完成ApplicationContext的实例化工作。例如：

//装载单个配置文件实例化ApplicationContext容器
ApplicationContext cxt = new ClassPathXmlApplicationContext
("applicationContext.xml");
//装载多个配置文件实例化ApplicationContext容器
String[] configs = {"bean1.xml","bean2.xml","bean3.xml"};
ApplicationContext cxt = new ClassPathXmlApplicationContext(configs);

下面是具体步骤：

一、属性注入

属性注入即通过 setAttribute 方法注入Bean 的属性值或依赖的对象。属性注入使用元素, 使用 name 属性指定 Bean 的属性名称，value 属性或子节点指定属性值。

1、创建一个bean类DBParaProperty

package com;

public class DBParaProperty {
 //jdbc sqlserver 驱动类
 String sqlServerDriverClassName;
 //sqlserver 连接地址
 String sqlServerUrl;
 //sqlserver 用户名
 String sqlServerUserName;
 //sqlserver 密码
 String sqlServerPassword;

 public String getSqlServerDriverClassName(){
 return this.sqlServerDriverClassName;
 }

 public void setSqlServerDriverClassName(String sqlServerDriverClassName){
 this.sqlServerDriverClassName = sqlServerDriverClassName;
 }

 public String getSqlServerUrl(){
 return this.sqlServerUrl;
 }

 public void setSqlServerUrl(String sqlServerUrl){
 this.sqlServerUrl = sqlServerUrl;
 }

 public String getSqlServerUserName(){
 return this.sqlServerUserName;
 }

 public void setSqlServerUserName(String sqlServerUserName){
 this.sqlServerUserName = sqlServerUserName;
 }

 public String getSqlServerPassword(){
 return this.sqlServerPassword;
 }

 public void setSqlServerPassword(String sqlServerPassword){
 this.sqlServerPassword = sqlServerPassword;
 }
}

2、创建一个xml文件

文件内容如下

<?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 http://www.springframework.org/schema/beans/spring-beans.xsd">
 <bean id="DBParaProperty" class="com.DBParaProperty">
 <property name="sqlServerDriverClassName" value="com.microsoft.sqlserver.jdbc.SQLServerDriver"></property>
 <property name="sqlServerUrl" value="jdbc:sqlserver://127.0.0.1:1433;databaseName=test;"></property>
 <property name="sqlServerUserName" value="saDBParaProperty"></property>
 <property name="sqlServerPassword" value="admin123"></property>
 </bean>
</beans>

3、在Controller中使用

package test;

import com.DBParaConstructor;
import com.DBParaProperty;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
@RequestMapping("/test2")
public class test2 {
 @RequestMapping("/test")
 @ResponseBody
 public Object test2() {
 //如果xml文件在src下面的话，直接写文件名就行
 ApplicationContext cpxac = new ClassPathXmlApplicationContext("DBParaProperty.xml");
 //根据bean节点的标识获取对象，id
 DBParaProperty dbParaProperty = (DBParaProperty) cpxac.getBean("DBParaProperty");
 System.out.println(dbParaProperty.getSqlServerUserName());

 return dbParaProperty.getSqlServerUserName();
 }
}

二、构造器注入

通过构造方法注入Bean 的属性值或依赖的对象，它保证了 Bean 实例在实例化后就可以使用。构造器注入在元素里声明属性。

步骤如下：

1、创建DBParaConstructor类

package com;

public class DBParaConstructor {
 //jdbc sqlserver 驱动类
 public String sqlServerDriverClassName;
 //sqlserver 连接地址
 public String sqlServerUrl;
 //sqlserver 用户名
 public String sqlServerUserName;
 //sqlserver 密码
 public String sqlServerPassword;

 public DBParaConstructor(){}

 public DBParaConstructor(String sqlServerDriverClassName,String sqlServerUrl,String sqlServerUserName,String sqlServerPassword){
 this.sqlServerDriverClassName = sqlServerDriverClassName;
 this.sqlServerUrl = sqlServerUrl;
 this.sqlServerUserName = sqlServerUserName;
 this.sqlServerPassword = sqlServerPassword;
 }
}

2、在src下面的文件夹test下创建一个xml文件。

<?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 http://www.springframework.org/schema/beans/spring-beans.xsd">
 <bean id="DBParaConstructor" class="com.DBParaConstructor">
 <constructor-arg name="sqlServerDriverClassName" value="com.microsoft.sqlserver.jdbc.SQLServerDriver"></constructor-arg>
 <constructor-arg name="sqlServerUrl" value="jdbc:sqlserver://127.0.0.1:1433;databaseName=test;"></constructor-arg>
 <constructor-arg name="sqlServerUserName" value="saDBParaConstructor"></constructor-arg>
 <constructor-arg name="sqlServerPassword" value="admin456"></constructor-arg>
 </bean>
</beans>

3、在Controller中使用

package test;

import com.DBParaConstructor;
import com.DBParaProperty;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
@RequestMapping("/test2")
public class test2 {
 @RequestMapping("/test")
 @ResponseBody
 public Object test2() {
 ApplicationContext cpxac = new ClassPathXmlApplicationContext("DBParaProperty.xml");
 DBParaProperty dbParaProperty = (DBParaProperty) cpxac.getBean("DBParaProperty");
 System.out.println(dbParaProperty.getSqlServerUserName());

 ApplicationContext acc = new ClassPathXmlApplicationContext("/test/DBParaConstructor.xml");
 DBParaConstructor dbParaConstructor = (DBParaConstructor)acc.getBean("DBParaConstructor");
 System.out.println(dbParaConstructor.sqlServerUserName);

 return dbParaProperty.getSqlServerUserName()+"*****"+dbParaConstructor.sqlServerUserName;
 }
}

项目目录如下：