spring boot前传(二):读取外部资源文件
通过@PropertySource可以指定读取的配置文件，通过@Value注解获取值，具体用法见案例代码中的注释！
这里我们以初始化数据源dataSource为例来演示
工程目录
阿里巴巴开源的Durid数据源配置文件
=========================druidConfig.properties================================
driverClassName=com.mysql.jdbc.Driver
url=jdbc\:mysql\://localhost\:3306/schooldb
duridUserName=root
password=123456
#配置监控统计拦截的filters，去掉后监控界面sql无法统计
filters=stat
#配置初始化大小
initialSize=6
#配置初始化最大连接数
maxActive=20
#配置最小空闲连接数
minIdle=3
#配置获取连接等待超时的时间,1分钟
maxWait=60000
#检测连接是否有效的SQL
validationQuery=SELECT 'x'
#申请连接的时候检测，如果空闲时间大于timeBetweenEvictionRunsMillis，执行validationQuery检测连接是否有效
testWhileIdle=true
#申请连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能
testOnBorrow=false
#归还连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能
testOnReturn=false
#启用PSCache，必须配置大于0，当大于0时，poolPreparedStatements自动触发修改为true
maxPoolPreparedStatementPerConnectionSize=20
#对于长时间不使用的连接强制关闭
removeAbandoned=true
#超过30秒的空闲连接就可以被关闭了,单位是秒
removeAbandonedTimeout=30
#配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
timeBetweenEvictionRunsMillis=10000
#配置一个连接在池中最小生存的时间，单位是毫秒
minEvictableIdleTimeMillis=30000===============================SpringConfig.java=========================
package com.wx.config;
import java.sql.SQLException;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import com.alibaba.druid.pool.DruidDataSource;
import com.wx.dao.IUserDao;
import com.wx.dao.UserDaoImpl;
//通过该注解来表明该类是一个Spring的配置，相当于一个传统的ApplicationContext.xml
@Configuration
// 相当于配置文件里面的pom配置
==========================pom.xml==================================
4.0.0
com.wx
bootpre02
0.0.1-SNAPSHOT
org.springframework
spring-core
4.3.3.RELEASE
org.springframework
spring-beans
4.3.3.RELEASE
org.springframework
spring-context
4.3.3.RELEASE
org.springframework
spring-expression
4.3.3.RELEASE
log4j
log4j
1.2.17
com.alibaba
druid
1.0.9
mysql
mysql-connector-java
5.1.26
${project.artifactId}
org.apache.maven.plugins
maven-resources-plugin
UTF-8
org.apache.maven.plugins
maven-compiler-plugin
1.7
1.7
UTF-8
实体类
==============================UserEntity.java=====================
package com.wx.entitys;
import java.io.Serializable;
public class UserEntity implements Serializable {
private static final long serialVersionUID = 1034088741557780953L;
private Integer userId;
private String userName;
private String passWord;
private String email;
public UserEntity() {
}
public UserEntity(String userName, String passWord) {
super();
this.userName = userName;
this.passWord = passWord;
}
public Integer getUserId() {
return userId;
}
public void setUserId(Integer userId) {
this.userId = userId;
}
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;
}
public void setEmail(String email) {
this.email = email;
}
public String getEmail() {
return email;
}
}
=========================================UserDaoImpl.java==========================
package com.wx.dao;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import com.wx.entitys.UserEntity;
@Component("userDao")
public class UserDaoImpl implements IUserDao {
@Autowired
private DataSource dataSource;
public List queryUserList(){
List userList = new ArrayList();
Connection conn=null;
try {
conn=dataSource.getConnection();
PreparedStatement psmt=conn.prepareStatement("select * from users");
ResultSet rs=psmt.executeQuery();
UserEntity user=null;
while(rs.next()){
user=new UserEntity();
user.setUserId(rs.getInt("userId"));
user.setUserName(rs.getString("userName"));
user.setPassWord(rs.getString("passWord"));
user.setEmail(rs.getString("email"));
userList.add(user);
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
try {
if(conn!=null){
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
return userList;
}
}
=============================UserBiz.java=========================
package com.wx.biz;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;
import com.wx.dao.IUserDao;
import com.wx.entitys.UserEntity;
@Service
public class UserBiz {
//Autowired默认根据类型进行装配，Qualifier根据名称装配
@Autowired
@Qualifier("userDao")
private IUserDao userDao;
public List queryUserList(){
return userDao.queryUserList();
}
}
测试类
==================TestConfig01.java==============================package com.wx.test;
import java.util.List;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import com.wx.biz.UserBiz;
import com.wx.config.SpringConfig;
import com.wx.entitys.UserEntity;
public class TestConfig01 {
public static void main(String[] args) {
//通过java配置来实例化spring容器
AnnotationConfigApplicationContext ctx=
new AnnotationConfigApplicationContext(SpringConfig.class);
//在spring容器中获取bean对象
//名称userBiz是注解根据类UserBiz自动生成的
UserBiz userBiz=(UserBiz)ctx.getBean("userBiz");
//或者采取下面的方式
//UserBiz userBiz=(UserBiz)ctx.getBean(UserBiz.class);
List userList=userBiz.queryUserList();
for(UserEntity user:userList){
System.out.print(user.getUserId());
System.out.print("\t"+user.getUserName());
System.out.print("\t"+user.getPassWord());
System.out.println("\t"+user.getEmail());
}
try {
Thread.sleep(100000);
} catch (InterruptedException e) {
e.printStackTrace();
}
//销毁容器
ctx.destroy();
}
}
可以从sqlyog界面观察数据源是否正常启动
如果本文帮助到了您，请点个赞吧！