2019/11/19 學習筆記

白天

Spring AOP

參考鏈接：https://blog.csdn.net/JinXYan/article/details/89302126

個人理解：Aop就是對OOP的補充，把我們各個業務組件中要用到的一些和業務核心功能無關的功能給抽出來，比如日誌功能，基本上每個業務組件都要用到，但是卻和我們的業務核心功能無關，這時候就應該把日誌功能給抽出來。

可以發現運行結果和執行順序
@Around->@Before->事件->@Around->@After->@AfterReturnings

Spring + Mybatis 簡單整合

建立一個Maven項目
引入相應依賴（網上看了很多案例，使用引用的依賴有點多）

<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.qing</groupId>
  <artifactId>spring_mybaties2</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  
  <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.build.timestamp.format>yyyyMMddHHmmss</maven.build.timestamp.format>
        <spring.version>5.2.0.RELEASE</spring.version>
        <mybatis.version>3.4.4</mybatis.version>
        <mybatisspring.version>1.3.1</mybatisspring.version>
        <jackson.version>2.7.0</jackson.version>
        <log4j.version>1.2.17</log4j.version>
        <slf4j.version>1.7.7</slf4j.version>
    </properties>
   
  <dependencies>
  <dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.12</version>
  <scope>test</scope>
  </dependency>
   <dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.12</version>
 
  </dependency>
 <dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>5.2.0.RELEASE</version>
</dependency>
  
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-core</artifactId>
  <version>5.2.0.RELEASE</version>
</dependency>
<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-test</artifactId>
  <version>5.2.0.RELEASE</version>
</dependency>
	<dependency>
	  <groupId>org.springframework</groupId>
	  <artifactId>spring-beans</artifactId>
	  <version>5.2.0.RELEASE</version>
	</dependency>

  <dependency>
	  <groupId>org.springframework</groupId>
	  <artifactId>spring-jdbc</artifactId>
	  <version>5.2.0.RELEASE</version>
	</dependency>

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>
        <dependency>
  <groupId>org.mybatis</groupId>
  <artifactId>mybatis-spring</artifactId>
  <version>2.0.3</version>
</dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        
  </dependencies>

</project>

然後建好相應層次，Dao層和entity層
UserDao：

package com.qing.test.dao;

import java.util.List;

import com.qing.test.entity.User;

public interface UserDao {
	 public void insert(User user);

     public void delete(int userId);

     public void update(User user);

     public User findById(int userID);

     public List<User> findAll();
}

User：

package com.qing.test.entity;

import java.io.Serializable;

public class User implements Serializable{
	private int userID;
	private String userName;
	private String userPwd;
	
	public int getUserID() {
		return userID;
	}
	public void setUserID(int userID) {
		this.userID = userID;
	}
	public User() {
		super();
	}
	public User(String userName, String userPwd) {
		super();
		this.userName = userName;
		this.userPwd = userPwd;
	}
	public User(int userID, String userName, String userPwd) {
		super();
		this.userID = userID;
		this.userName = userName;
		this.userPwd = userPwd;
	}
	@Override
	public String toString() {
		return "User [userID=" + userID + ", userName=" + userName + ", userPwd=" + userPwd + "]";
	}
	public String getUserName() {
		return userName;
	}
	public void setUserName(String userName) {
		this.userName = userName;
	}
	public String getUserPwd() {
		return userPwd;
	}
	public void setUserPwd(String userPwd) {
		this.userPwd = userPwd;
	}
	
}

然後建立Dao層對應的mybatis映射文件：
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.qing.test.dao.UserDao">
	<resultMap type="com.qing.test.entity.User" id="userResult">
              <!--其中id爲主鍵，result爲普通字段,property對應實體類屬性，column對應字段名（更準確的說應該是查詢結果集中的字段名）-->
              <id property="userID" column="user_id"/>
              <result property="userName" column="user_name"/>
              <result property="userPwd" column="user_pwd"/>
       </resultMap>
       
       <!-- 插入數據後獲得自增主鍵的值 -->
       <insert id="insert" keyProperty="id" keyColumn="user_id">
              INSERT INTO user
                     (user_name,user_pwd)
              VALUES
                     (#{userName},#{userPwd})
       </insert>
       
       <!-- 修改用戶內容 -->
       <update id="update">
              UPDATE user
              SET
                     user_name=#{userName},
                     user_pwd=#{userPwd},
              WHERE
                     user_id=#{userID}
       </update>
       
       <!-- 根據id刪除用戶 -->
       <delete id="delete">
              DELETE FROM user WHERE user_id=#{userID}
       </delete>
       
       <!-- 根據id查詢用戶 -->
       <select id="findById" resultMap="userResult">
              SELECT user_id,user_name,user_pwd FROM user WHERE user_id=#{userID}
       </select>
       
       <!-- 查詢所有用戶 -->
       <select id="findAll" resultMap="userResult">
              SELECT user_id,user_name,user_pwd FROM user
       </select>
</mapper>

然後建立Mybatis和Spring配置文件（最簡化只配置了一些東西）
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:aop="http://www.springframework.org/schema/aop"
	xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jdbc="http://www.springframework.org/schema/jdbc"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="
     http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
     http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
     http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.0.xsd
     http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
     http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
     http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">
	
   <context:annotation-config />
	
   <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">  
		<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
      	<property name="url" value="jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8"/>
      	<property name="username" value="root"/>
      	<property name="password" value="root"/>
   </bean>
	
	<bean id="sqlSession" class="org.mybatis.spring.SqlSessionFactoryBean">
	<property name="typeAliasesPackage" value="com.qing.test.entity" />
		<property name="dataSource" ref="dataSource"/>
		<property name="mapperLocations" value="mapper/*.xml"/>
	</bean>

	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
		<property name="basePackage" value="com.qing.test.dao"/>
	</bean>
	
</beans>

這裏的東西很少，日誌也沒有增加，數據庫也只配置了基本的東西
最後是測試類：

package spring_mybaties2;


import java.util.List;


import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.qing.test.dao.UserDao;
import com.qing.test.entity.User;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class Test {

	@Autowired
	private UserDao userDao;
	@org.junit.Test
	public void testAdd() {
		User user = new User();
		user.setUserName("liao qing");
		user.setUserPwd("1234");
		userDao.insert(user);
	}
	@org.junit.Test
	public void testList() {
		List<User> users=userDao.findAll();
		for (User user : users) {
			System.out.println(user);
		}
	}

}

遇到的問題：
Caused by: java.lang.ClassNotFoundException: org.mybatis.spring.SqlSessionFactoryBean

需要引入mybatis-spring依賴

浪費了很多時間，要一步一步來，可以先試試mybatis有沒有通，再解決spring的問題

2019/11/19 學習筆記

2019/11/19 學習筆記

白天

Spring AOP

Spring + Mybatis 簡單整合

公司剛入職了一名 Java 中級開發，短短 4 行代碼居然湊齊了 3 個 bug！我哭了~~

公衆號5月C#/.NET熱文一覽

git 下載大陸鏡像地址

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