注解/xml配置
新建工程springmvcdemo即相应的包:
并将输出路径改为Tomcat的webapps下:
部署完毕后运行Tomcat,浏览器页面显示“Hello world!”,说明Tomcat工作正常。
在pom.xml中添加mysql、SpringMVC相关等依赖:
<?xml version="1.0" encoding="UTF-8"?>
<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.bit</groupId>
<artifactId>SpringMVC2</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>SpringMVC2 Maven Webapp</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.7</maven.compiler.source>
<maven.compiler.target>1.7</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.0.1</version>
<scope>provided</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.el/javax.el-api -->
<dependency>
<groupId>javax.el</groupId>
<artifactId>javax.el-api</artifactId>
<version>3.0.0</version>
</dependency>
</dependencies>
<build>
<finalName>SpringMVC</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>3.1.0</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>3.8.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
</plugin>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>3.2.2</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>
</project>
首先,写tools包下的DbManager类,该类用来连接数据库:其属性需要username、password、driver、url:
package com.bit.tools;
import java.sql.*;
//
public class DbManager {
public String username="root";
public String password="jdpy1229jiajia";
public String driver="com.mysql.jdbc.Driver";
public String url="jdbc:mysql://localhost:3306/ming";
public Connection connection=null;
public Statement statement=null;
public ResultSet resultSet=null;
//无参构造
public DbManager(){}
//获取数据库连接
public Connection getConnection()
{
try {
Class.forName(driver);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
System.out.println("加载数据库成功");
try {
connection=DriverManager.getConnection(url,username,password);
System.out.println("数据库连接成功");
} catch (SQLException e) {
e.printStackTrace();
}
return connection;
}
//执行全查query all of form user
public ResultSet executeQueryForUser(String sql)
{
connection=this.getConnection();
try {
statement=connection.createStatement();
resultSet=statement.executeQuery(sql);
return resultSet;
} catch (SQLException e) {
e.printStackTrace();
}
return null;}
//关闭连接
public void closeConnection() throws SQLException {
if(resultSet!=null) {
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if(statement!=null)
statement.close();
if(connection!=null)
connection.close();
}
}
在resources下新建SpringMVC的配置文件springmvcservlet.xml:
通过<context:component-scan base-package=<“com.bit.controller”/>可以扫描到控制器:
<?xml version="1.0" encoding="ISO-8859-1"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx" xmlns:p="http://www.springframework.org/schema/p"
xmlns:util="http://www.springframework.org/schema/util"
xmlns:cache="http://www.springframework.org/schema/cache"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.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.xsd
http://www.springframework.org/schema/cache
http://www.springframework.org/schema/cache/spring-cache-3.1.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util.xsd">
<context:component-scan base-package="com.bit.controller"/>
<mvc:annotation-driven/>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
<property name="prefix" value="/jsps/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
在webapp下新建jsps文件夹,其中新建showuser,jsp:
<%--
Created by IntelliJ IDEA.
User: Lenovo
Date: 2019/8/9
Time: 20:23
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<%@taglib prefix="c" uri="http://java.sun.com/jstl/core_rt" %>>
<html>
<head>
<title>Title</title>
</head>
<body>
<table border="1" align="center" width="100%">
<tr>
<th>
UserId
</th>
<th>
UserName
</th>
<th>
UserAddr
</th>
</tr>
<c:forEach items="${userListKey}" var="user">
<tr>
<td>${user.userId}</td>
<td>${user.userName}</td
<td>${user.userAddr}</td>
</tr>
</c:forEach>
</table>
</body>
</html>
接下来,在web.xml中配置前端控制器:
<!DOCTYPE web-app PUBLIC
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app>
<display-name>Archetype Created Web Application</display-name>
<!--配置前端控制器-->
<servlet>
<servlet-name>myspringmvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvcservlet.xml</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>myspringmvc</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
接下来,写Controller,通过@Controller注解的方式:
import com.bit.po.User;
import com.bit.service.UserServiceImpl;
import com.bit.service.UserServive;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
import java.util.List;
@Controller
public class UserController {
//自行维护UserController类与UserService类之间的关系
private UserServive userServive=new UserServiceImpl();
//映射
@RequestMapping(value="/queryUser")
//接收请求,响应并跳转
public ModelAndView queryUser() throws Exception {
List<User> userList= userServive.queryUserService();
ModelAndView modelAndView=new ModelAndView();
//通过key与value进行转向
modelAndView.addObject("userListKey",userList);
//通过视图解析器来解析
modelAndView.setViewName("showuser");
return modelAndView;
}
}
在service包中需要一个UserService接口:
package com.bit.service;
import com.bit.po.User;
import java.util.List;
public interface UserServive
{public List<User> queryUserService() throws Exception;
}
在po包中新建User类,该类的属性需要与数据库中的表对应:
package com.bit.po;
public class User {
private int userId;
private String userName;
private String userAddr;
//默认的无参构造
public User(){}
@Override
public String toString() {
return "User{" +
"userId=" + userId +
", userName='" + userName + '\'' +
", userAddr='" + userAddr + '\'' +
'}';
}
public int getUserId() {
return userId;
}
public void setUserId(int userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getUserAddr() {
return userAddr;
}
public void setUserAddr(String userAddr) {
this.userAddr = userAddr;
}
}
在service包中写实现类UserServiceImpl:
package com.bit.service;
import com.bit.dao.UserDao;
import com.bit.po.User;
import java.util.List;
public class UserServiceImpl implements UserServive{
private UserDao userDao=new UserDao();
//Service层需要调用dao
@Override
public List<User> queryUserService() throws Exception {
return userDao.queryUserDao();
}
}
service层需要调用dao,dao需要访问数据库。在dao包中写UserDao类:
package com.bit.dao;
import com.bit.po.User;
import com.bit.tools.DbManager;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
//dao层需要访问数据库
public class UserDao {
public List<User> queryUserDao()
{List<User> userList=null;
try{
String str="select * from user";
ResultSet resultSet=new DbManager().executeQueryForUser(str);
userList=new ArrayList<User>();
while (resultSet.next())
{User user=new User();
user.setUserId(resultSet.getInt("userid"));
user.setUserName(resultSet.getString("username"));
user.setUserAddr(resultSet.getString("useraddr"));
userList.add(user);}
return userList;}
catch (Exception ex)
{ex.printStackTrace();}
return userList;
}
}
运行Tomcat,浏览器显示结果为:
上述代码存在问题:在controller类和service类中都用到了new关键字,应该让Spring容器去创建类、管理类与类之间的关系。拷贝一份UserController2.,并在resources中新建springmvcbeans.xml:
在web.xml中修改使Spring能扫描到新增加的xml:
<param-value>classpath:springmvc*.xml</param-value>
并在springmvcbeans.xml中配置适配器和处理器:
<!--配置适配器-->
<bean id="simpleControllerHandlerAdapter" class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"/>
<!--配置处理器-->
<bean id="userController2" name="/userController2" class="com.bit.controller.UserController2"/>
<!--配置映射器-->
<bean id="beanNameUrlHandlerMapping" class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>
那么UserContraller2类需要实现Controller接口:
接下来,在springmvcbeans.xml中声明servive、dao、po等层的bean,需要servive包下的UserServiveImpl类提供getter、setter方法,而不再是在该类中自行new UserDao类,修改UserDao类:
package com.bit.service;
import com.bit.dao.UserDao;
import com.bit.po.User;
import java.util.List;
public class UserServiceImpl implements UserServive {
private UserDao userDao;
public UserDao getUserDao() {
return userDao;
}
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
@Override
public List<User> queryUserService() throws Exception {
return userDao.queryUserDao();
}
}
同理,UserController2类中不需要new UserServiveImpl,只需要提供setter、getter方法:
修改UserController2类:
package com.bit.controller;
import com.bit.po.User;
import com.bit.service.UserServiceImpl;
import com.bit.service.UserServive;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.List;
public class UserController2 implements Controller {
private UserServive userServive;
public UserServive getUserServive() {
return userServive;
}
public void setUserServive(UserServive userServive) {
this.userServive = userServive;
}
public ModelAndView handleRequest(HttpServletRequest var1, HttpServletResponse var2) throws Exception {
List<User> userList=userServive.queryUserService();
ModelAndView modelAndView=new ModelAndView();
modelAndView.addObject("userListKey",userList);
modelAndView.setViewName("showuser");
return modelAndView; }
}
那么这时UserController2类中拥有了UserServive属性,可以通过调用setter方法:
<!--配置处理器-->
<bean id="userController2" name="/userController2" class="com.bit.controller.UserController2">
<property name="UserServive" ref="userServive">
</property>
</bean>
在springmvcbeans.xml中声明servive、dao、po等层的bean,
<!--servive-->
<bean id="userServive" class="com.bit.service.UserServiceImpl">
<property name="userDao" ref="userDAo"/>
</bean>>
<!--Dao-->
<bean id="userDAo" class="com.bit.dao.UserDao"/>
通过XML配置的方式,运行Tomcat,浏览器显示结果为:
在springmvcservlet.xml中添加:
<context:component-scan base-package="com.bit.service"/>
(!!!!!直接扫描整个com.bit包才行。否则会报500错误。)
这样Spring就可以扫描到service包,对service包中的UserServiveImpl类使用@Service注解,即可。而接下来需要让Controller找到这个Service,只需在UserController类中加上@Autowired注解。
接下来,给dao包下的UserDao类添加@Component注解:
UserServiveImpl类调用了UserDao,因此需要在UserDao属性前加@Autowired注解,这时就不再需要UserDao属性的getter、setter方法了:
配置与注解是不可以混用的。
推荐使用注解。