Druid介绍
Druid是Java语言中最好的数据库连接池。Druid能够提供强大的监控和扩展功能。
Druid是阿里巴巴开源平台上的一个项目,整个项目由数据库连接池、插件框架和SQL解析器组成。该项目主要是为了扩展JDBC的一些限制,可以让程序员实现一些特殊的需求,比如向密钥服务请求凭证、统计SQL信息、SQL性能收集、SQL注入检查、SQL翻译等,程序员可以通过定制来实现自己需要的功能。
Druid首先是一个数据库连接池,但它不仅仅是一个数据库连接池,它还包含一个ProxyDriver,一系列内置的JDBC组件库,一个SQL Parser。
Druid支持所有JDBC兼容的数据库,包括Oracle、MySql、Derby、Postgresql、SQL Server、H2等等。
Druid针对Oracle和MySql做了特别优化,比如Oracle的PS Cache内存占用优化,MySql的ping检测优化
首先,强大的监控特性,通过Druid提供的监控功能,可以清楚知道连接池和SQL的工作情况。
●监控SQL的执行时间、ResultSet持有时间、返回行数、更新行数、错误次数、错误堆栈信息。
●SQL执行日志,Druid提供了不同的LogFilter,能够支持Common-Logging、Log4j和JdkLog,你可以按需要选择相应的LogFilter,监控你应用的数据库访问情况。
●SQL执行的耗时区间分布。什么是耗时区间分布呢?比如说,某个SQL执行了1000次,其中0~1毫秒区间50次,1~10毫秒800次,10~100毫秒100次,100~1000毫秒30次,1~10秒15次,10秒以上5次。通过耗时区间分布,能够非常清楚知道SQL的执行耗时情况。
●监控连接池的物理连接创建和销毁次数、逻辑连接的申请和关闭次数、非空等待次数、PSCache命中率等。
其次,方便扩展。Druid提供了Filter-Chain模式的扩展API,可以自己编写Filter拦截JDBC中的任何方法,可以在上面做任何事情,比如说性能监控、SQL审计、用户名密码加密、日志等等。
Druid内置提供了用于监控的StatFilter、日志输出的Log系列Filter、防御SQL注入攻击的WallFilter。
阿里巴巴内部实现了用于数据库密码加密的CirceFilter,以及和Web、Spring关联监控的DragoonStatFilter。
第三,Druid集合了开源和商业数据库连接池的优秀特性,并结合阿里巴巴大规模苛刻生产环境的使用经验进行优化。
●ExceptionSorter。当一个连接产生不可恢复的异常时,例如Oracle error_code_28 session has been killed,必须立刻从连接池中逐出,否则会产生大量错误。目前只有Druid和JBoss DataSource实现了ExceptionSorter。
●PSCache内存占用优化对于支持游标的数据库(Oracle、SQL Server、DB2等,不包括MySql),PSCache可以大幅度提升SQL执行性能。一个PreparedStatement对应服务器一个游标,如果PreparedStatement被缓存起来重复执行,PreparedStatement没有被关闭,服务器端的游标就不会被关闭,性能提高非常显著。在类似“SELECT * FROM T WHERE ID = ?”这样的场景,性能可能是一个数量级的提升。但在Oracle JDBC Driver中,其他的数据库连接池(DBCP、JBossDataSource)会占用内存过多,极端情况可能大于1G。Druid调用OracleDriver提供管理PSCache内部API。
●LRU是一个性能关键指标,特别Oracle,每个Connection对应数据库端的一个进程,如果数据库连接池遵从LRU,有助于数据库服务器优化,这是重要的指标。Druid、DBCP、Proxool、JBoss是遵守LRU的。BoneCP、C3P0则不是。BoneCP在mock环境下性能可能还好,但在真实环境中则就不好了。
Druid提供了MySql、Oracle、Postgresql、SQL-92的SQL的完整支持,这是一个手写的高性能SQL Parser,支持Visitor模式,使得分析SQL的抽象语法树很方便。
简单SQL语句用时10微秒以内,复杂SQL用时30微秒。
通过Druid提供的SQL Parser可以在JDBC层拦截SQL做相应处理,比如说分库分表、审计等。Druid防御SQL注入攻击的WallFilter就是通过Druid的SQL Parser分析语义实现的。
Druid的优势是在JDBC最低层进行拦截做判断,不会遗漏。
项目介绍(能跑起来就好)
创建一个登陆页面,输入username和password,如果和数据库对应,则跳转的success.jsp,否则跳转到error.jsp
此项目是在我以前的SSM整合的代码该的,所以项目名称有些对不上,根据你tomcat下的名称就好
项目下载
项目运行展示
http://localhost:8080/SSMMaven/druid/sql.html
搭建(Maven)项目
和Druid有关的配置:
web.xml(添加一个Filter和servlet)
修改pom.xml(添加Druid依赖)
修改Spring的配置文件applicationContext.xml中的dataSource
项目结构
修改pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.imooc</groupId> <artifactId>SSMMaven</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>war</packaging> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <!-- 单元测试 --> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> <!-- 日志 --> <!-- 实现slf4j接口并整合 --> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.1.1</version> </dependency> <!-- io --> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.2</version> </dependency> <!-- Servlet web --> <dependency> <groupId>taglibs</groupId> <artifactId>standard</artifactId> <version>1.1.2</version> </dependency> <dependency> <groupId>jstl</groupId> <artifactId>jstl</artifactId> <version>1.2</version> <scope>compile</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> <scope>compile</scope> </dependency> <!-- 数据库 --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.39</version> </dependency> <!-- druid --> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.0.7</version> </dependency> <!-- 数据库连接池 c3p0 <dependency> <groupId>c3p0</groupId> <artifactId>c3p0</artifactId> <version>0.9.1.2</version> </dependency> --> <!-- Spring --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>4.3.10.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>4.3.10.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>4.3.10.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>4.3.10.RELEASE</version> </dependency> <!-- Spring MVC --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>4.3.10.RELEASE</version> </dependency> <!-- MyBatis --> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.4.1</version> </dependency> <!-- MyBatis-Spring --> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>1.3.0</version> </dependency> </dependencies> </project>
添加Spring的配置文件
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd"> <!-- 配置自动扫描的包,使其自动注入到IOC容器 --> <context:component-scan base-package="com.imooc.service"></context:component-scan> <!-- 导入资源文件 --> <context:property-placeholder location="classpath:db.properties" /> <!-- 配置数据源 --> <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"> <property name="username" value="${jdbc.user}"></property> <property name="password" value="${jdbc.password}"></property> <property name="driverClassName" value="${jdbc.driverClass}"></property> <property name="url" value="${jdbc.jdbcUrl}"></property> <!-- 初始化连接大小 --> <property name="initialSize" value="0"></property> <!-- 连接池最大使用连接数量 --> <property name="maxActive" value="20"></property> <!-- 连接池最小空闲 --> <property name="minIdle" value="0" /> <!-- 获取连接最大等待时间 --> <property name="maxWait" value="60000" /> <property name="validationQuery"> <value>SELECT 1</value> </property> <property name="testOnBorrow" value="false" /> <property name="testOnReturn" value="false" /> <property name="testWhileIdle" value="true" /> <!-- 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 --> <property name="timeBetweenEvictionRunsMillis" value="60000" /> <!-- 配置一个连接在池中最小生存的时间,单位是毫秒 --> <property name="minEvictableIdleTimeMillis" value="25200000" /> <!-- 打开removeAbandoned功能 --> <property name="removeAbandoned" value="true" /> <!-- 1800秒,也就是30分钟 --> <property name="removeAbandonedTimeout" value="1800" /> <!-- 关闭abanded连接时输出错误日志 --> <property name="logAbandoned" value="true" /> <!-- 监控数据库 --> <!-- <property name="filters" value="stat" /> --> <property name="filters" value="mergeStat" /> </bean> <!-- 配置MyBatis的SqlSession --> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <!-- 配置MyBatis的配置的文件 --> <property name="configLocation" value="classpath:mybatis.xml"></property> </bean> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <!-- 自动扫描 com.imooc.dao下的interface,并加入IOC容器 --> <property name="basePackage" value="com.imooc.dao" /> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property> </bean> <!-- 开启事务 --> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource" /> </bean> <!-- 可通过注解控制事务 --> <tx:annotation-driven transaction-manager="transactionManager" /> </beans>
配置SpringMVC的配置文件
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd 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-4.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd"> <!-- 配置自动扫描的包,自动加入WebIoc容器中 --> <context:component-scan base-package="com.imooc.handler"></context:component-scan> <!-- 配置视图解析器, --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/"></property> <property name="suffix" value=".jsp"></property> </bean> <!-- 处理静态资源文件,303校验等等(标配,必须写) --> <mvc:default-servlet-handler/> <mvc:annotation-driven></mvc:annotation-driven> </beans>
MyBatis的配置文件
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <!-- =====>设置别名: 将com.imooc.entity.User设置为User 如果不设置别名<select id="selectDemo" resultType="com.imooc.entity.User"> ***</select> 设置别名 <select id="selectDemo" resultType="User">***</select> --> <typeAliases> <package name="com.imooc.entity"></package> </typeAliases> <mappers> <mapper resource="com/imooc/mapper/UserMapper.xml" /> </mappers> </configuration>
数据库信息
jdbc.user=root jdbc.password=root jdbc.driverClass=com.mysql.jdbc.Driver jdbc.jdbcUrl=jdbc:mysql://localhost:3306/text jdbc.initPoolSize=5 jdbc.maxPoolSize=10 #...
修改web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>SSMMaven</display-name> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <!-- 设置字符过滤器,防止乱码 --> <filter> <filter-name>characterEncodingFilter</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> <init-param> <param-name>forceEncoding</param-name> <param-value>true</param-value> </init-param> </filter> <filter-mapping> <filter-name>characterEncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!-- SpringMVC --> <servlet> <servlet-name>springDispatcherServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext-mvc.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>springDispatcherServlet</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <!-- Spring --> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value> </context-param> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <!-- 经常需要排除一些不必要的url,比如.js,/jslib/等等。配置在init-param中。比如 --> <filter> <filter-name>DruidWebStatFilter</filter-name> <filter-class>com.alibaba.druid.support.http.WebStatFilter</filter-class> <init-param> <param-name>exclusions</param-name> <param-value>*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*</param-value> </init-param> </filter> <filter-mapping> <filter-name>DruidWebStatFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!-- druid的Servlet --> <servlet> <servlet-name>DruidStatView</servlet-name> <servlet-class>com.alibaba.druid.support.http.StatViewServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>DruidStatView</servlet-name> <url-pattern>/druid/*</url-pattern> </servlet-mapping> </web-app>
dao层
package com.imooc.dao; public interface UserMapper { //传入username返回password String selectPassword(String username); }
dao层的Mapper.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.imooc.dao.UserMapper"> <select id="selectPassword" resultType="String"> select password from user where username = #{username} </select> </mapper>
实体层
package com.imooc.entity; public class User { private Integer id; private String username; private String password; public User() { super(); } public User(String username, String password) { super(); this.username = username; this.password = password; } /* * (non-Javadoc) * * @see java.lang.Object#toString() */ @Override public String toString() { return "User [id=" + id + ", username=" + username + ", password=" + password + "]"; } /** * @return the id */ public Integer getId() { return id; } /** * @param id * the id to set */ public void setId(Integer id) { this.id = id; } /** * @return the username */ public String getUsername() { return username; } /** * @param username * the username to set */ public void setUsername(String username) { this.username = username; } /** * @return the password */ public String getPassword() { return password; } /** * @param password * the password to set */ public void setPassword(String password) { this.password = password; } }
控制层Controller
package com.imooc.handler; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import com.imooc.entity.User; import com.imooc.service.UserService; @Controller public class LoginHandler { @Autowired private UserService userService; @RequestMapping("/login.action") public String login(User user){ String password=userService.login(user.getUsername()); if(!user.getPassword().equals(password)){ return "error"; }else{ return "success"; } } /** * @return the userService */ public UserService getUserService() { return userService; } /** * @param userService the userService to set */ public void setUserService(UserService userService) { this.userService = userService; } public LoginHandler() { System.out.println("------------->LoginController"); } }
service层
package com.imooc.service; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import com.imooc.dao.UserMapper; @Service public class UserService { @Autowired private UserMapper userDao; public String login(String username){ return userDao.selectPassword(username); } public UserService() { super(); } /** * @return the userDao */ public UserMapper getUserDao() { return userDao; } /** * @param userDao the userDao to set */ public void setUserDao(UserMapper userDao) { this.userDao = userDao; } }
index.jsp登录页面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <form action="login.action" method="post"> username<input type="text" name="username"><br/> password<input type="password" name="password"><br/> <input type="submit" value="Submit"> </form> </body> </html>
success.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Insert title here</title> </head> <body> success.jsp </body> </html>
error.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Insert title here</title> </head> <body> error.jsp </body> </html>