【maven】記第一次基於SSM框架+maven的整合嘗試

【開發IDE】

InteIliJ IDEA 2019.3.3 (Ultimate Edition)

JDK 13.0.2

Apache Maven 3.6.3

MySQL Community Server 8.0.19

最近在學習maven，主要學習資料來源於B站：https://www.bilibili.com/video/BV1VE411Z77m?p=30

跟着視頻自己也走了一遍基於SSM框架+maven的項目構建，特此記錄下來。

這個demo很簡單，從MySQL中讀取數據並展示到頁面上。

項目整體架構如下圖所示：

項目詳細構建過程

創建基於maven骨架web-app的新工程並命名爲【ssm_maven】，並手動補齊main下的java和resources目錄以及test/jave目錄，並記得指定Source Roots，創建好以後的目錄結構如下：

#-> pom.xml文件導入項目依賴的jar包及其他約束

由於本次項目基於SSM框架構建，涉及jar包衆多也版本衝突問題也比較多，所以這個文件一般都是拿別人寫好的文件自己進行修改即可。完整的pom.xml如下

<?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.yy</groupId>
    <artifactId>ssm_maven</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>ssm_maven Maven Webapp</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <properties>
        <!--jdk版本控制-->
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>13</maven.compiler.source>
        <maven.compiler.target>13</maven.compiler.target>

        <!--  集中定義依賴版本號 -->
        <mybatis.version>3.5.4</mybatis.version>
        <mybatis.spring.version>2.0.4</mybatis.spring.version>
        <mysql.version>8.0.19</mysql.version>
        <!--        <druid.version>1.1.21</druid.version>--> <!--最新版有bug-->
        <druid.version>1.1.20</druid.version>
        <spring.version>5.2.4.RELEASE</spring.version>
        <jstl.version>1.2</jstl.version>
        <servlet-api.version>4.0.1</servlet-api.version>
        <jsp-api.version>2.0</jsp-api.version>
        <jackson.version>2.10.3</jackson.version>
        <slf4j.version>1.7.30</slf4j.version>
        <spring.security.version>5.3.0.RELEASE</spring.security.version>
    </properties>

    <!-- 鎖定jar包版本 -->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-context</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-web</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-webmvc</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-tx</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-test</artifactId>
                <version>${spring.version}</version>
            </dependency>
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>${mybatis.version}</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>${druid.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <!-- MyBatis -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>${mybatis.version}</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>${mybatis.spring.version}</version>
        </dependency>
        <!--分頁-->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>5.1.11</version>
        </dependency>
        <!-- MySql -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.19</version>
            <scope>runtime</scope>
        </dependency>
        <!-- 連接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>${druid.version}</version>
        </dependency>

        <dependency>
            <groupId>c3p0</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.1.2</version>
            <scope>compile</scope>
        </dependency>

        <!-- Spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jms</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- Spring security -->
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-web</artifactId>
            <version>${spring.security.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-config</artifactId>
            <version>${spring.security.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-core</artifactId>
            <version>${spring.security.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-taglibs</artifactId>
            <version>${spring.security.version}</version>
        </dependency>

        <!-- JSP相關 -->
        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>${jstl.version}</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>${servlet-api.version}</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jsp-api</artifactId>
            <version>${jsp-api.version}</version>
            <scope>provided</scope>
        </dependency>

        <!-- 日誌 -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j.version}</version>
            <scope>test</scope>
        </dependency>
        <!-- SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder". -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>1.6.6</version>
        </dependency>

        <!-- test -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.2</version>
                <!--    <configuration>-->
                <!--        <port>8080</port>-->
                <!--    </configuration>-->
            </plugin>
        </plugins>
    </build>
</project>

這裏有三點需要說明

（1）由於這裏使用的jdk是JavaSE13，所以直接指定這裏的-source和-target爲13了，其實只要7以上都可以。

<maven.compiler.source>13</maven.compiler.source>
<maven.compiler.target>13</maven.compiler.target>

（2）必須添加Tomcat7插件，maven自帶的Tomcat默認是6的版本。

<plugin>
    <groupId>org.apache.tomcat.maven</groupId>
    <artifactId>tomcat7-maven-plugin</artifactId>
    <version>2.2</version>
    <!--    <configuration>-->
    <!--        <port>8080</port>-->
    <!--    </configuration>-->
</plugin>

以上兩點可以參考我之前寫的一篇blog：https://blog.csdn.net/coralime/article/details/104699219

（3）注意這裏的連接池druid的版本是1.1.20，沒有使用最新版1.1.21，可以參考我之前寫的另一篇blog：https://blog.csdn.net/coralime/article/details/105032941

#1-> dao層代碼編寫

#1.1-> main/java/ -> [package] com.yy.domain -> [pojo] User.java

MySQL數據庫中的user表如下

User.java中的屬性名需和user表中字段名保持一致。

package com.yy.domain;

public class User {

    private int user_id;
    private String username;
    private String birthdate;

    public User() {}

    public int getUser_id() {
        return user_id;
    }

    public void setUser_id(int user_id) {
        this.user_id = user_id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getBirthdate() {
        return birthdate;
    }

    public void setBirthdate(String birthdate) {
        this.birthdate = birthdate;
    }

    @Override
    public String toString() {
        return "User{" +
                "user_id=" + user_id +
                ", username='" + username + '\'' +
                ", birthdate='" + birthdate + '\'' +
                '}';
    }
}

#1.2-> main/java/ -> [package] com.yy.dao -> [interface] UserDao.java （注意這裏是接口文件）

package com.yy.dao;
import com.yy.domain.User;

public interface UserDao {
    public User findAllById(int id);
}

#1.3-> main/resources/ -> [Directory] com/yy/dao -> [xml] UserDao.xml

resources目錄下創建接口文件UserDao.java的映射文件mapper時，這裏不再是package而是直接創建Directory即可，注意路徑和接口文件路徑保持一致，不然找不到，另外這裏的mapper文件名也需要和接口名保持一致。

<?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.yy.dao.UserDao">
    <!-- <select id="findAllById" parameterType="int" resultType="com.yy.domain.User">-->
    <!-- 寫別名user也是可以的 -->
    <select id="findAllById" parameterType="int" resultType="user">
        select * from user where user_id = #{id};
    </select>
</mapper>

在指定resultType的時候可以直接指定類型“com.yy.domain.User”，也可以寫別名，一旦寫了別名需要在配置文件中添加掃描才行，可以忽略大小寫，但名稱還是要和pojo名保持一致，即這裏pojo名是“User”，別名只能寫“User”或“user”。

#1.4-> main/resources/ -> [xml] applicationContext.xml

編寫spring配置文件，添加DAO層配置

<!--  DAO層配置文件開始    -->
<!-- 配置數據連接池-->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
    <!--MySQL6以後的新版本-->
    <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
    <property name="url" value="jdbc:mysql://localhost/maven_db"/>
    <property name="username" value="root"/>
    <property name="password" value="1007"/>
</bean>

<!-- 配置生產SqlSession對象的工廠-->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
    <property name="dataSource" ref="dataSource"/>
    <!-- 掃描pojo包，給包下所有的pojo對象起別名 User->user此時user這個別名就可以直接使用了 -->
    <property name="typeAliasesPackage" value="com.yy.domain"/>
</bean>

<!-- 掃描接口包路徑，生成包下所有接口的代理對象，並且放入spring容器中 -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <property name="basePackage" value="com.yy.dao"/>
</bean>
<!--   DAO層配置文件結束   -->

#2-> Service層代碼編寫

#2.1-> main/java/ -> [package] com.yy.service -> [interface] UserService.java （注意這裏是接口文件）

爲了簡單演示，這裏UserService實現的功能和UserDao保持一致。

package com.yy.service;

import com.yy.domain.User;

public interface UserService {

    public User findAllById(int id);

}

#2.2-> main/java/ -> [package] com.yy.service.impl -> [java] UserServiceImpl.java （接口的實現類文件）

package com.yy.service.impl;

import com.yy.dao.UserDao;
import com.yy.domain.User;
import com.yy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl implements UserService {

    /* Filed Injection 變量注入警告 */
//    @Autowired
//    private UserDao userDao;

    /* spring推薦-構造器依賴注入 */
    private UserDao userDao;
    @Autowired
    public UserServiceImpl(UserDao userDao) {
        this.userDao = userDao;
    }
    
    /* setter方式注入 */
//    private UserDao userDao;
//    @Autowired
//    public void setUserDao(UserDao userDao){
//        this.userDao = userDao;
//    }

    @Override
    public User findAllById(int id) {
        return userDao.findAllById(id);
    }
}

關於@Autowired的注入問題可參考之前寫的一篇blog：https://blog.csdn.net/coralime/article/details/105013528

#2.3-> main/resources/ -> [xml] applicationContext.xml

編寫spring配置文件，添加Service層配置

<!--   Service配置文件開始   -->
<!--組件掃描配置-->
<context:component-scan base-package="com.yy.service"/>

<!--aop 面向切面編程，切面就是切入點和通知的組合-->
<!--配置事務管理器-->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="dataSource"/>
</bean>
<!--配置事務的通知-->
<tx:advice id="transactionInterceptor">
    <tx:attributes>
        <tx:method name="save*" propagation="REQUIRED"/>
        <tx:method name="update*" propagation="REQUIRED"/>
        <tx:method name="delete*" propagation="REQUIRED"/>
        <tx:method name="find*" read-only="true"/>
        <tx:method name="*" propagation="REQUIRED"/>
    </tx:attributes>
</tx:advice>

<!--配置切面-->
<aop:config>
    <aop:pointcut id="pointcut" expression="execution(* com.yy.service.impl.*.*(..))"/>
    <aop:advisor advice-ref="transactionInterceptor" pointcut-ref="pointcut"/>
</aop:config>
<!--   Service配置文件結束   -->

#TEST-> test/java/ -> [package] com.yy.test -> [class] UserTest.java

package com.yy.test;

import com.yy.dao.UserDao;
import com.yy.domain.User;
import com.yy.service.UserService;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UserTest {

    @Test
    public void findAllById() {
        // 獲取Spring容器
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");

        // -1- Dao(Mapper)測試 ----------------------------------
        // 從容器中拿到所需的Dao的代理對象
        UserDao userDao = applicationContext.getBean(UserDao.class);
        // 調用方法
        User user = userDao.findAllById(1);
        System.out.println(user.toString());

        // -2- Service測試     ----------------------------------
        // 從容器中拿到所需的Service的代理對象
        UserService userService = applicationContext.getBean(UserService.class);
        // 調用方法
        User user1 = userService.findAllById(2);
        System.out.println(user1.toString());
    }
}

輸出結果

User{user_id=1, username='Lay Zhang', birthdate='1991-10-07'}
User{user_id=2, username='Lee Joongi', birthdate='1982-04-17'}

至此，Dao層和Service層都編寫完畢，且測試通過沒有問題，接下來寫Web層的邏輯。

附上完整的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"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       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
			    http://www.springframework.org/schema/mvc
			    http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--    DAO層配置文件開始    -->
    <!--配置數據連接池-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <!--MySQL6以後的新版本-->
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost/maven_db"/>
        <property name="username" value="root"/>
        <property name="password" value="1007"/>
      </bean>

    <!-- 配置生產SqlSession對象的工廠-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <!-- 掃描pojo包，給包下所有的pojo對象起別名 User->user此時user這個別名就可以直接使用了 -->
        <property name="typeAliasesPackage" value="com.yy.domain"/>
    </bean>

    <!-- 掃描接口包路徑，生成包下所有接口的代理對象，並且放入spring容器中 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.yy.dao"/>
    </bean>
    <!--   DAO層配置文件結束   -->

    <!--   Service配置文件開始   -->
    <!--組件掃描配置-->
    <context:component-scan base-package="com.yy.service"/>

    <!--aop 面向切面編程，切面就是切入點和通知的組合-->
    <!--配置事務管理器-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
     </bean>
    <!--配置事務的通知-->
    <tx:advice id="transactionInterceptor">
        <tx:attributes>
            <tx:method name="save*" propagation="REQUIRED"/>
            <tx:method name="update*" propagation="REQUIRED"/>
            <tx:method name="delete*" propagation="REQUIRED"/>
            <tx:method name="find*" read-only="true"/>
            <tx:method name="*" propagation="REQUIRED"/>
        </tx:attributes>
    </tx:advice>

    <!--配置切面-->
    <aop:config>
        <aop:pointcut id="pointcut" expression="execution(* com.yy.service.impl.*.*(..))"/>
        <aop:advisor advice-ref="transactionInterceptor" pointcut-ref="pointcut"/>
    </aop:config>
    <!--   Service配置文件結束   -->
</beans>

#3-> Web層代碼編寫

#3.1-> main/java/ -> [package] com.yy.controller -> [java] UserController.java

由於頁面還沒有進行編寫，這裏的model需要設置的key值和最終return的頁面地址我們先空着不寫。

package com.yy.controller;

import com.yy.domain.User;
import com.yy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("users")
public class UserController {

    // 構造器依賴注入UserService
    private UserService userService;
    @Autowired
    public UserController(UserService userService) {
        this.userService = userService;
    }

    @RequestMapping("findUsers")
    public String findUsers(Model model){
        User user = userService.findAllById(1);
        /* 查詢到user之後需要放進model裏面 並設置key值 */
        model.addAttribute("",user);
        /* 具體跳轉到哪一個頁面 */
        return "";
    }
}

#3.2-> main/resources/ -> [xml] springmvc.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"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       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
			    http://www.springframework.org/schema/mvc
			    http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 組件掃描 -->
    <context:component-scan base-package="com.yy.controller"/>

    <!-- 處理器映射器 處理器適配器 -->
    <mvc:annotation-driven/>

    <!-- 視圖解析器 -->
    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!-- 前綴-頁面放在文件夾路徑 /WEB-INF/pages/ 下 -->
        <property name="prefix" value="/WEB-INF/pages/"/>
        <!-- 後綴-頁面以.jsp結尾 -->
        <property name="suffix" value=".jsp"/>
        <!-- 完整的路徑：/WEB-INF/pages/xxx.jsp -->
    </bean>

    <!-- 釋放靜態資源 防止servlet的"/"攔截了所有資源，包括靜態資源 -->
    <mvc:default-servlet-handler/>

</beans>

#3.3-> main/webapp/WEB-INF/ -> [Directory] pages -> userInfo.jsp

<%--
  Created by IntelliJ IDEA.
  User: Coralime
  Date: 2020/3/22
  Time: 15:54
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
    <title>userInfo</title>
</head>
<body>
<form>
    <table width="100%" border="1">
        <tr>
            <td>user_id</td>
            <td>${userinfo.user_id}</td>
        </tr>
        <tr>
            <td>username</td>
            <td>${userinfo.username}</td>
        </tr>
        <tr>
            <td>birthdate</td>
            <td>${userinfo.birthdate}</td>
        </tr>
    </table>
</form>
</body>
</html>

頁面配置完成，注意頁面取值使用的是EL表達式，key值爲“userinfo”，另外頁面存放地址爲 src/main/webapp/WEB-INF/pages/userInfo.jsp

現在可以回過頭去完善UserController.java

#3.4-> 完善 main/java/com.yy.controller.UserController.java

- 查詢到user之後需放進model裏面，以key-value的方式註解。映射到前端頁面userInfo.jsp中，這裏的key就是EL表達式中的userinfo。

- return頁面的實際地址: src/main/webapp/WEB-INF/pages/userInfo.jsp

因爲在springmvc.xml裏的視圖解析器中配置了[前綴]和[後綴]，所以這裏可以直接寫頁名userInfo即可。

package com.yy.controller;

import com.yy.domain.User;
import com.yy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("users")
public class UserController {

    // 構造器依賴注入UserService
    private UserService userService;
    @Autowired
    public UserController(UserService userService) {
        this.userService = userService;
    }

    @RequestMapping("findUsers")
    public String findUsers(Model model){
        User user = userService.findAllById(1);
        /* 查詢到user之後需要放進model裏面
         * 以key-value的方式註解，映射前端頁面
         * key -> userInfo.jsp中EL表達式中的userinfo */
        model.addAttribute("userinfo",user);
        /* 具體跳轉到哪一個頁面的地址: /WEB-INF/pages/userInfo.jsp
         * 因爲在springmvc.xml裏的視圖解析器中配置了[前綴]和[後綴]
         * 所以這裏可以直接寫頁名就行 */
        return "userInfo";
    }
}

#3.5-> main/webapp/WEB-INF/ -> web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <!-- 編碼過濾器 -->
    <filter>
        <filter-name>encodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <!--private String encoding;-->
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <!--public void setForceEncoding(boolean forceEncoding)-->
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <!-- /* 所有地址全部攔截 -->
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!-- 配置spring核心監聽器 -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <!-- 重新指定spring配置文件的路徑 -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext.xml</param-value>
    </context-param>

    <!-- 配置springMVC的核心Servlet -->
    <servlet>
        <servlet-name>dispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!-- 配置springmvc.xml文件 -->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
        <!-- 讓這個文件首先加載，優先級最高 -->
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

啓動tomcat7:run，打開瀏覽器輸入：http://localhost:8080/ssm_maven/users/findUsers 回車

一點說明：tomcat啓動以後在console輸出的地址是 http://localhost:8080/ssm_maven/

但要訪問到userInfo.jsp頁面必須按上面那個地址來，具體映射關係如下：

【maven】記第一次基於SSM框架+maven的整合嘗試

SQL優化-20231016

【SpringBoot】第一次運行SpringBoot的HelloWorld Demo錯誤記錄

【MySQL】安裝MySQL 8.0.19中遇到的問題小結

【maven】記第一次使用maven創建web工程遇到的坑

【maven】webapp項目發佈到 weblogic 資源文件報錯404找不到

【spring】關於@Autowired警告的一點說明

https://yachay.unat.edu.pe/blog/index.php?comment_area=format_blog&comment_component=blog&comment_co

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