寫在前面:2020年面試必備的Java後端進階面試題總結了一份複習指南在Github上,內容詳細,圖文並茂,有需要學習的朋友可以Star一下!
GitHub地址:https://github.com/abel-max/Java-Study-Note/tree/master
SSM框架簡介
無論你是前端,APP,後端開發工程師,搭建一個自己的後臺對於學習都是很有幫助的,本文是作者搭建SSM後端環境的記錄,閱讀完本文你也可以快速搭建一個屬於自己的後端代碼。
SSM框架是Spring MVC ,Spring和Mybatis 框架 的整合,是標準的MVC模式,將整個系統劃分爲View層,Controller層,Service層,DAO層四層,使用Spring MVC負責請求的轉發和視圖管理,Spring實現業務對象管理,Mybatis作爲數據對象的持久化引擎。
數據庫配置
首先我們創建一個數據庫和表。
創建數據庫的SQL
CREATE DATABASE time_manager_app
創建數據表的SQL
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`id` int(8) NOT NULL COMMENT '主鍵',
`name` varchar(255) COLLATE utf8_bin NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
向數據表中插入一條數據
INSERT INTO `user` VALUES ('1', '1');
創建工程
現在我們打開IDEA創建我們的maven工程
File->New->Project
選擇maven,選中紅框中的選項,點擊Next
紅框中的兩個選項隨便輸入,點擊Next
紅框中選擇本地安裝的maven軟件的位置,點擊Next
點擊finish
現在我們的maven工程就創建好了
接下來我們要創建一些工程需要的文件夾
右鍵選擇SRC->NEW->Directory
創建好的文件目錄如下
右鍵JAVA將它設置爲Source Root
右鍵resource將它設置爲Resources Root
工程創建完畢,接下來我們編寫我們需要的配置文件
配置文件編寫
首先我們在POM.XML中添加我們需要的依賴包
注意,複製時從備註裏的copy開始,複製到copy結束,不要整個文件複製
<?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.ssmtest</groupId>
<artifactId>ssmtest</artifactId>
<version>1.0-SNAPSHOT</version>
<!--從這裏開始copy -->
<!-- 用來設置版本號 -->
<properties>
<spring.version>4.2.4.RELEASE</spring.version>
<mybatis.version>3.2.8</mybatis.version>
<slf4j.version>1.7.12</slf4j.version>
<log4j.version>1.2.17</log4j.version>
<druid.version>1.0.9</druid.version>
</properties>
<!-- 用到的jar包 -->
<dependencies>
<!-- 單元測試 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<!-- 表示開發的時候引入,發佈的時候不會加載此包 -->
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>1.6.8</version>
</dependency>
<!-- spring框架包 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-oxm</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-jdbc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</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-expression</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>${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>
<!-- spring框架包 -->
<!-- mybatis框架包 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>${mybatis.version}</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>1.2.2</version>
</dependency>
<!-- mybatis框架包 -->
<!-- 數據庫驅動 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.35</version>
</dependency>
<!-- 導入dbcp的jar包,用來在applicationContext.xml中配置數據庫 -->
<dependency>
<groupId>commons-dbcp</groupId>
<artifactId>commons-dbcp</artifactId>
<version>1.4</version>
</dependency>
<!-- jstl標籤類 -->
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- log -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</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>
</dependency>
<!-- 連接池 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>${druid.version}</version>
</dependency>
<!--加入對json轉換-->
<!-- JSON: jackson -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>2.5.0</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.5.0</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.5.0</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.jr</groupId>
<artifactId>jackson-jr-all</artifactId>
<version>2.5.0</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.46</version>
</dependency>
<dependency>
<groupId>c3p0</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.1.2</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
</dependencies>
<build>
<finalName>jackwu</finalName>
<!-- java編譯插件,如果maven的設置裏配置好jdk版本就不用 -->
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.2</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
<!--打包配置文件-->
<resources>
<resource>
<directory>src\main\resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
<include>**/*.tld</include>
</includes>
<filtering>false</filtering>
</resource>
<resource>
<directory>src\main\java</directory>
<excludes>
<exclude>**/*.java</exclude>
</excludes>
</resource>
</resources>
</build>
<!--copy在這裏結束 -->
</project>
PS:如果你的網絡環境不好,Maven下載依賴包需要一段時間,不要着急,繼續接下來的配置就可以了
接下來我們在WEB-INF目錄下創建web.xml
web.xml內容如下,整個copy就可以
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
version="3.1">
<!-- 配置加載類路徑的配置文件 -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath*:applicationContext.xml</param-value>
</context-param>
<!-- 配置監聽器 -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<listener>
<listener-class>org.springframework.web.context.request.RequestContextListener</listener-class>
</listener>
<!-- 解決中文亂碼過濾器 -->
<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>
</filter>
<filter-mapping>
<filter-name>characterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- 前端控制器(加載classpath:springmvc.xml 服務器啓動創建servlet) -->
<servlet>
<servlet-name>dispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!-- 配置初始化參數,創建完DispatcherServlet對象,加載springmvc.xml配置文件 -->
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-mvc.xml</param-value>
</init-param>
<!-- 服務器啓動的時候,讓DispatcherServlet對象創建 -->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcherServlet</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>
接着我們在resources文件夾下創建applicationContext.xml
同樣內容整個複製
<?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">
<!-- 開啓註解掃描,管理service和dao -->
<context:component-scan base-package="service">
</context:component-scan>
<context:component-scan base-package="dao">
</context:component-scan>
<context:property-placeholder location="classpath:db.properties"/>
<!-- 配置連接池 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="${jdbc.driver}"/>
<property name="jdbcUrl" value="${jdbc.url}"/>
<property name="user" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</bean>
<!-- 把交給IOC管理 SqlSessionFactory -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
</bean>
<!-- 掃描dao接口 -->
<bean id="mapperScanner" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="dao"/>
</bean>
<!-- 配置Spring的聲明式事務管理 -->
<!-- 配置事務管理器 -->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager"/>
</beans>
接着我們在resource文件夾下創建spring-mvc.xml
同樣內容整個複製
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:mvc="http://www.springframework.org/schema/mvc"
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"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.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
">
<!-- 掃描controller的註解,別的不掃描 -->
<context:component-scan base-package="controller">
</context:component-scan>
<!-- 配置視圖解析器 -->
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<!-- JSP文件所在的目錄 -->
<property name="prefix" value="/pages/" />
<!-- 文件的後綴名 -->
<property name="suffix" value=".jsp" />
</bean>
<!-- 開啓對SpringMVC註解的支持 -->
<mvc:annotation-driven />
<!--
支持AOP的註解支持,AOP底層使用代理技術
JDK動態代理,要求必須有接口
cglib代理,生成子類對象,proxy-target-class="true" 默認使用cglib的方式
-->
<!--
支持AOP的註解支持,AOP底層使用代理技術
JDK動態代理,要求必須有接口
cglib代理,生成子類對象,proxy-target-class="true" 默認使用cglib的方式
-->
<aop:aspectj-autoproxy proxy-target-class="true"/>
<!-- 輸出對象轉JSON支持 -->
<bean
class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
<property name="messageConverters">
<list>
<bean
class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="supportedMediaTypes">
<list>
<value>text/html;charset=UTF-8</value>
<value>text/plain;charset=UTF-8</value>
<value>application/json;charset=UTF-8</value>
</list>
</property>
</bean>
</list>
</property>
</bean>
</beans>
接着我們在resource文件夾下創建db.properties
同樣內容整個複製
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/time_manager_app?characterEncoding=utf-8
jdbc.username=rootjdbc.password=root
現在我們的工程文件結構是這樣的
接下來我們要編寫我們的java代碼
Java代碼編寫
首先我們創建幾個需要的文件夾
接着我們在相應的文件夾下創建我們的java文件
文件結構如下
每個文件下的代碼如下
UserController
package controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import service.UserService;
@Controller
@RequestMapping("/user")
public class UserController {
@Autowired
private UserService userService;
@RequestMapping("/find.do")
@ResponseBody
public Object findAll(){
Object a = userService.findAll(); System.out.println(a);
return a;
}}
UserDao
package dao;
import org.apache.ibatis.annotations.Select;
import pojo.User;
import java.util.List;
public interface UserDao {
@Select("select * from user")
public List<User> findAll();
}
User
package pojo;
public class User {
private int id;
private String name;
public int getId() {
return id;
} public void setId(int id) {
this.id = id;
} public String getName() {
return name;
} public void setName(String name) {
this.name = name;
}}
UserServiceImpl
package service.impl;
import dao.UserDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import pojo.User;
import service.UserService;
import java.util.List;
@Service
@Transactional
public class UserServiceImpl implements UserService {
@Autowired
private UserDao userDao;
public List<User> findAll(){
return userDao.findAll();
}}
UserService
package service;
import pojo.User;
import java.util.List;
public interface UserService {
public List<User> findAll();
}
到這裏代碼應該是沒有錯誤的.如果有錯誤,可能是依賴包沒有下載好,等待一下
接下來我們配置tomcat
配置tomcat
點擊idea右上角的位置,接着點擊edit
按順序點擊紅色框的位置
在紅框處選擇tomcat版本
接着配置我們的war包,點擊紅色框處
選擇第二個
清空application context中的內容,點擊apply
NO NO NO配置中間我們出現了一個問題
應該把resource文件夾更名爲resources Sorry
正確的工程路徑如下
啓動程序
接下來我們要啓動我們的程序,測試是否配置成功
按順序點擊紅框處
等待打包成功,會出現target文件夾,控制檯log如下
接着點擊綠色箭頭,啓動程序
測試
打開我們的瀏覽器,輸入 http://localhost :8080/user/find.do
Amazing數據庫中的一條數據已經成功返回了,到此我們的SSM工程配置成功。