Spring --17.Spring中的核心監聽器ContextLoaderListener
阿新 • • 發佈：2018-11-19
開發環境：
JDK 1.8
Idea 2017
Tomcat:apache-tomcat-8
Spring:5.0.71、概述
ContextLoaderListener是Spring中的核心監聽器，當web工程啟動時，
該監聽器負責建立Spring的IOC容器，存放在ServletContext中；當需要用IOC容器時，就從ServletContext中獲取。
好處：
1、不用我們手動建立IOC容器，由監聽器負責建立；
2、可以保證整個工程中只有一個IOC容器；
2、建立web工程、引入依賴
工程目錄：
建立工程模板
匯入依賴pom.xml
<dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> <!-- JSP相關 --> <dependency> <groupId>jstl</groupId> <artifactId>jstl</artifactId> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jsp-api</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>5.0.7.RELEASE</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> </dependency> <!-- jdbc模板 --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>com.day04_tx</groupId> <artifactId>Spring_tx</artifactId> <version>0.0.1-SNAPSHOT</version> <scope>compile</scope> </dependency> </dependencies> <build> <plugins> <!-- 配置Tomcat外掛 --> <plugin> <groupId>org.apache.tomcat.maven</groupId> <artifactId>tomcat7-maven-plugin</artifactId> <configuration> <port>8080</port> <path>/</path> </configuration> </plugin> </plugins> <finalName>ContextLoaderListener</finalName> <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) --> <plugins> <plugin> <artifactId>maven-clean-plugin</artifactId> <version>3.0.0</version> </plugin> <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging --> <plugin> <artifactId>maven-resources-plugin</artifactId> <version>3.0.2</version> </plugin> <plugin> <artifactId>maven-compiler-plugin</artifactId> <version>3.7.0</version> </plugin> <plugin> <artifactId>maven-surefire-plugin</artifactId> <version>2.20.1</version> </plugin> <plugin> <artifactId>maven-war-plugin</artifactId> <version>3.2.0</version> </plugin> <plugin> <artifactId>maven-install-plugin</artifactId> <version>2.5.2</version> </plugin> <plugin> <artifactId>maven-deploy-plugin</artifactId> <version>2.8.2</version> </plugin> </plugins> </pluginManagement> </build>
3、建立相關類
AccountDao.java
package com.day04_listener.dao; import com.day04_listener.domain.Account; import java.util.List; /** * @ Author ：ShaoWei Sun. * @ Date ：Created in 9:36 2018/11/15 */ public interface AccountDao { /** * 查詢所有使用者資訊 * @return 返回集合 */ public abstract List<Account> findAll(); }
AccountDaoImpl.java
package com.day04_listener.dao.Impl;
import com.day04_listener.dao.AccountDao;
import com.day04_listener.domain.Account;
import com.day04_listener.rowmapper.AccountRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import java.util.List;
/**
*
* @ Author ：ShaoWei Sun.
* @ Date ：Created in 9:38 2018/11/15
*/
public class AccountDaoImpl implements AccountDao {
//jdbcTemplate依賴注入
private JdbcTemplate jdbcTemplate;
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}
/**
* 查詢所有使用者資訊
* @return 返回集合
*/
@Override
public List<Account> findAll() {
List<Account> list = this.jdbcTemplate.query("SELECT id,name,money FROM account ", new AccountRowMapper());
return list;
}
}
AccountService.java
package com.day04_listener.service;
import com.day04_listener.domain.Account;
import java.util.List;
/**
* @ Author ：ShaoWei Sun.
* @ Date ：Created in 9:50 2018/11/15
*/
public interface AccountService {
/**
* 查詢所有使用者資訊
* @return 返回集合
*/
List<Account> findAllAccount();
}
AccountServiceImpl.java
package com.day04_listener.service.Imlp;
import com.day04_listener.dao.AccountDao;
import com.day04_listener.domain.Account;
import com.day04_listener.service.AccountService;
import java.util.List;
/**
* @ Author ：ShaoWei Sun.
* @ Date ：Created in 9:53 2018/11/15
*/
public class AccountServiceImpl implements AccountService {
//accountDao依賴注入、set方法
private AccountDao accountDao;
public void setAccountDao(AccountDao accountDao) {
this.accountDao = accountDao;
}
/**
* 查詢所有使用者資訊
* @return 返回集合
*/
@Override
public List<Account> findAllAccount() {
return accountDao.findAll();
}
}
Account.java
package com.day04_listener.domain;
import java.io.Serializable;
/**
* @ Author ：ShaoWei Sun.
* @ Date ：Created in 8:50 2018/11/15
*/
public class Account implements Serializable {
private Long id;
private String name;
private Double money;
public Account(Long id, String name, Double money) {
this.id = id;
this.name = name;
this.money = money;
}
public Account() {
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Double getMoney() {
return money;
}
public void setMoney(Double money) {
this.money = money;
}
@Override
public String toString() {
return "Account{" +
"id=" + id +
", name='" + name + '\'' +
", money='" + money + '\'' +
'}';
}
}
AccountRowMapper.java 將資料庫資料轉換成java物件
package com.day04_listener.rowmapper;
import com.day04_listener.domain.Account;
import org.springframework.jdbc.core.RowMapper;
import java.sql.ResultSet;
import java.sql.SQLException;
/**將資料庫資料轉成java物件
* @ Author ：ShaoWei Sun.
* @ Date ：Created in 8:51 2018/11/15
*/
public class AccountRowMapper implements RowMapper<Account> {
@Override
public Account mapRow(ResultSet resultSet, int row) throws SQLException {
Account account = new Account();
account.setId(resultSet.getLong("id"));
account.setName(resultSet.getString("name"));
account.setMoney(resultSet.getDouble("money"));
return account;
}
}
AccountServlet.java
package com.day04_listener.servlet;
import com.day04_listener.domain.Account;
import com.day04_listener.service.AccountService;
import org.springframework.context.ApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;
/**
* @ Author ：ShaoWei Sun.
* @ Date ：Created in 10:03 2018/11/16
*/
public class AccountServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//從servletContext中獲取唯一的Ioc容器
ApplicationContext ac = WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
//從ioc容器中獲取AccountService
AccountService accountService = (AccountService) ac.getBean("accountService");
List<Account> list = accountService.findAllAccount();
request.setAttribute("accounts",list);
request.getRequestDispatcher("/accounts.jsp").forward(request,response);
}
}
4、把相關bean配置到Spring中
applicationContext.xml
<?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:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
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
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd">
<!--匯入jdbc-->
<context:property-placeholder location="classpath:jdbc.properties"/>
<bean id="accountService" class="com.day04_listener.service.Imlp.AccountServiceImpl">
<property name="accountDao" ref="accountDao"></property>
</bean>
<bean id="accountDao" class="com.day04_listener.dao.Impl.AccountDaoImpl">
<property name="jdbcTemplate" ref="jdbcTemplate"></property>
</bean>
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean>
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="driverClassName" value="${jdbc.driverClass}"></property>
<property name="url" value="${jdbc.url}"></property>
<property name="username" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>
<!--配置事務管理器-->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<!--注入資料來源-->
<property name="dataSource" ref="dataSource"></property>
</bean>
<!--配置事務的屬性-->
<tx:advice id="txAdvice" transaction-manager="transactionManager">
<tx:attributes>
<!--find開頭的方法加只讀事務、*表示萬用字元、匹配任意方法-->
<tx:method name="find*" read-only="true"/>
<!--其餘方法是加可讀寫的事務-->
<tx:method name="*"/>
</tx:attributes>
</tx:advice>
<!--配置事務的切面-->
<aop:config>
<!--配置切入點表示式、告訴框架哪些方法要控制事務-->
<aop:pointcut id="pt" expression="execution(* com.day04_listener.service.Imlp.*.*(..))"/>
<!--將定義好的事務屬性應用到上述切入點-->
<aop:advisor advice-ref="txAdvice" pointcut-ref="pt"/>
</aop:config>
</beans>jdbc.properties
jdbc.driverClass = com.mysql.jdbc.Driver
jdbc.url = jdbc:mysql://localhost:3306/mybatis
jdbc.username = root
jdbc.password = sswqzxlog4j.properties
### direct log messages to stdout ###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
### direct messages to file mylog.log ###
log4j.appender.file=org.apache.log4j.FileAppender
log4j.appender.file.File=D:/mylog.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
### set log levels - for more verbose logging change 'info' to 'debug' ###
log4j.rootLogger=debug, stdout, file
5、在web.xml中配置核心監聽器
webapp/WEB-INF/web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">
<!--指定Spring核心配置檔案路徑-->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</context-param>
<!--配置監聽器、當工程啟動時、建立IOC容器、存放在ServletContext中-->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!--配置servlet 可用註解@WebServlet("/accountServlet")-->
<servlet>
<servlet-name>AccountServlet</servlet-name>
<servlet-class>com.day04_listener.servlet.AccountServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AccountServlet</servlet-name>
<url-pattern>/accountServlet</url-pattern>
</servlet-mapping>
</web-app>6、建立jsp頁面
accounts.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!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>
<style type="text/css">
#customers {
font-family: "Trebuchet MS", Arial, Helvetica, sans-serif;
width: 100%;
border-collapse: collapse;
}
#customers td, #customers th {
font-size: 1em;
border: 1px solid #98bf21;
padding: 3px 7px 2px 7px;
}
#customers th {
font-size: 1.1em;
text-align: left;
padding-top: 5px;
padding-bottom: 4px;
background-color: #A7C942;
color: #ffffff;
}
#customers tr.alt td {
color: #000000;
background-color: #EAF2D3;
}
</style>
</head>
<body>
<table id="customers">
<tr>
<th>編號</th>
<th>姓名</th>
<th>餘額</th>
</tr>
<c:forEach items="${accounts}" var="account">
<tr>
<td>${account.id}</td>
<td>${account.name}</td>
<td>${account.money}</td>
</tr>
</c:forEach>
</table>
</body>
</html>