SSM integrated learning notes (mainly ideas)

ssm Will be spring,springmvc,mybatis These three frameworks are used together .
The first is to import jar package ：

• mybatis what is needed jar
• spring what is needed jar
• Database driven jar
• Data source needs jar
• spring And mybatis The middle of integration jar
• springmvc Of jar
  
  Import complete jar After that, let's show the project directory ：
  As shown in the figure below ：
  
  First of all, explain the idea , Is to write a simple query , The front desk passes in a id, Backstage basis id The user information can be found and transferred to the front page for display .
  Let me start by saying that I wrote this demo The main steps ：
• First of all, I don't need to say anything about creating tables , The table has two fields ,id and username
• Then create web engineering , Write web.xml file , It mainly writes a load spirng Configuration file listeners and springmvc Front end controller for
• And then in src Create these four configuration files under ,applicationContext.xml, db.properties, mybatis-config.xml, springmvc-config.xml
• Then create the package , These are the bags in the above figure ,controller,po, dao,service also service Implementation package for
• Then write springmvc You have to configure the file , There are three main contents in it , Write scanned packages , Configure annotation driver , Configure the view parser
• Then write mybatis Configuration file for , There is only one content in it , Just give po Add an alias to your package , In this way mapper There is no need to write the full name of the class
• Then write db.properties There are some database configurations
• Last write applicationContext This is the most troublesome , The main contents of the writing are ： First, introduction db.properties file , Configure data sources , Configure transaction manager , Open transaction annotation , To configure mybatis Factory sqlsessionfactory, To configure mapper Scanner , Configure scan service package
• Then you can write happily User, UserDao,UserDao.xml,service,serviceImpl,controller, This is some simple logic , In the business layer service Write the transaction annotations and business layer annotations on the implementation class of and inject dao, stay controller Write the control layer annotation , Inject service, And configure the access path on the method ,return success Complete jump to jsp page
• The next step is to write jsp 了 , stay WEB-INF Create folder jsp, establish success.jsp You can complete the jump ~
  Next is the specific code ：

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_3_0.xsd" version="3.0">
  <display-name>ssm</display-name>
  <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>
  
  <!--  To configure springmvc Front end controller for   -->
  <!-- The front controller of this Spring Web application, responsible for handling all application requests -->
	<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:config/springmvc-config.xml</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>

	<!-- Map all requests to the DispatcherServlet for handling -->
	<servlet-mapping>
		<servlet-name>springDispatcherServlet</servlet-name>
		<!--  Don't intercept jsp -->
		<url-pattern>/</url-pattern>
	</servlet-mapping>
	
	<!--  Configuration is loaded spring File listener  -->
	<!-- needed for ContextLoaderListener -->
	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>classpath:config/applicationContext.xml</param-value>
	</context-param>

	<!-- Bootstraps the root web application context before servlet initialization -->
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
	
</web-app>

springmvc-config.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: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">

	<!--  scanning , Specify the package to scan  -->
	<context:component-scan base-package="com.hou.controller"></context:component-scan>
	
	<!--  view resolver  -->
	<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value="/WEB-INF/jsp/"></property>
		<property name="suffix" value=".jsp"></property>
	</bean>
	
	<!--  Configure annotation driver  -->
	<mvc:annotation-driven></mvc:annotation-driven>
</beans>

mybatis-config.xml

<?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>
	<typeAliases>
		<package name="com.hou.po"/>
	</typeAliases>
</configuration>

db.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql:///user
jdbc.username=root
jdbc.password=123456
jdbc.maxTotal=30
jdbc.maxIdle=10
jdbc.initialSize=5

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-4.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
	
	<!--  Read db.properties -->
	<context:property-placeholder location="classpath:config/db.properties"/>
	
	<!--  Configure data sources  -->
	<bean id="dataSource" class="org.apache.commons.dbcp2.BasicDataSource">
		<property name="driverClassName" value="${jdbc.driver}"></property>
    	<property name="url" value="${jdbc.url}"></property>
    	<property name="username" value="${jdbc.username}"></property>
    	<property name="password" value="${jdbc.password}"></property>
    	<property name="maxTotal" value="${jdbc.maxTotal}"></property>
    	<property name="maxIdle" value="${jdbc.maxIdle}"></property>
    	<property name="initialSize" value="${jdbc.initialSize}"></property>
	</bean>
	
	<!--  Transaction manager   Depending on the data source  -->
	<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
		<property name="dataSource" ref="dataSource"></property>
	</bean>
	
	<!--  Open transaction annotation  -->
	<tx:annotation-driven />
	
	<!-- 
		 To configure mybatis factory sqlsessionfactory
		 You need to give him a data source and mybatis Core profile for 
	 -->
	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
		<property name="dataSource" ref="dataSource"></property>
		<property name="configLocation" value="classpath:config/mybatis-config.xml"></property>
	</bean>
	
	<!--  To configure mapper Scanner   be based on MapperScannerConfigure  Automatically generate the mapper through the interface in the package  -->
	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
		<!--  Specified package  -->
		<property name="basePackage" value="com.hou.dao"></property>
	</bean>
	
	<!--  scanning service -->
	<context:component-scan base-package="com.hou.service"></context:component-scan>
	
</beans>

UserDao.java

package com.hou.dao;

import com.hou.po.User;

public interface UserDao {
    
	
	/**
	 * 	 according to id Query user information 
	 */
	public User findUserById(Integer id);
}

UserDao.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.hou.dao.UserDao">
	<select id="findUserById" parameterType="Integer" resultType="User">
		select * from t_user where id=#{id}
	</select>
</mapper>

UserService.java

package com.hou.service;

import com.hou.po.User;

public interface UserService {
    
	public User findUserById(Integer id);
}

UserSercviceImpl.java

package com.hou.service.impl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.hou.dao.UserDao;
import com.hou.po.User;
import com.hou.service.UserService;

@Service
@Transactional
public class UserSercviceImpl implements UserService {
    
	// Inject UserDao
	@Autowired
	private UserDao userDao;
	
	public User findUserById(Integer id) {
    
		return this.userDao.findUserById(id);
	}
}

UserController.java

package com.hou.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import com.hou.po.User;
import com.hou.service.UserService;

@Controller
public class UserController {
    
	// Inject service
	@Autowired
	private UserService userService;
	
	@RequestMapping("/findUserById")
	public String findUserById(Integer id, Model model) {
    
		User user = this.userService.findUserById(id);
		System.out.println(user);
		model.addAttribute("user", user);
		return "success";
	}
}

success.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>
	ok
	<br> Here is the user information found ：<br>
	id:${user.id}<br>
	username:${user.username}
</body>
</html>

Running environment ：tomcat v8.5
Run a screenshot ： Manually add /findUserById?id=2（ Query with a parameter , Successfully jump to success And display ）

Console output ： Above about SSL Warning of , We are testing , Don't mind . About SSL： You can use Baidu or reference ：https://www.cnblogs.com/mysql-dba/p/7061300.html

Database table structure ： The truth is , Consider the length of the field , I used it for convenience 255

Database table data ：

At present, we are considering using ajax and json To interact with the front and back …