maven构建项目,整合ssm(2 整合mybatis)

完整的代码请见码云  https://gitee.com/liuhuxiang/simplemavendemo

1 下载mysql 

这一步就不详述了,网上的教程有很多,小伙伴自行参考,有个点要注意下,高版本的mysql下载完成后,用navicat等客户端连接会有错误,建议下载4.1.17以下的版本

具体参考: https://blog.csdn.net/sun19910114/article/details/39118045

创建数据库

CREATE DATABASE liuhuxiang;

查询数据库

show databases;

进入数据库

use liuhuxiang;

创建测试表

DROP TABLE IF EXISTS `user_t`;
CREATE TABLE `user_t` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_name` varchar(40) NOT NULL,
  `password` varchar(255) NOT NULL,
  `age` int(4) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
insert  into `user_t`(`id`,`user_name`,`password`,`age`) values (1,'测试','sfasgfaf',24);

2 pom文件配置

通过maven去下载pom文件中指定的jar,主要包括一些spring的核心包,mybatis,dbcp,以及log4j的包,一次性提供给大家,通过命令 mvn clean install:install下载包,如果发现下载速度太慢的话,就去用阿里云镜像,享受飞速下载。。。

<?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>cn.liuhuxiang</groupId>
  <artifactId>simplemavendemo</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>simplemavendemo 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>
    <!-- spring版本号 -->
    <spring.version>4.0.2.RELEASE</spring.version>
    <!-- mybatis版本号 -->
    <mybatis.version>3.2.6</mybatis.version>
    <!-- log4j日志文件管理包版本 -->
    <slf4j.version>1.7.7</slf4j.version>
    <log4j.version>1.2.17</log4j.version>
  </properties>

  <!--依赖的jar-->
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <!-- spring核心包 -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-oxm</artifactId>
      <version>${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-webmvc</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-support</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <!-- mybatis核心包 -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>${mybatis.version}</version>
    </dependency>
    <!-- mybatis/spring包 -->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.2.2</version>
    </dependency>
    <!-- 导入java ee jar 包 -->
    <dependency>
      <groupId>javax</groupId>
      <artifactId>javaee-api</artifactId>
      <version>7.0</version>
    </dependency>
    <!-- 导入Mysql数据库链接jar包 -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.30</version>
    </dependency>
    <!-- 导入dbcp的jar包,用来在applicationContext.xml中配置数据库 -->
    <dependency>
      <groupId>commons-dbcp</groupId>
      <artifactId>commons-dbcp</artifactId>
      <version>1.2.2</version>
    </dependency>
    <!-- JSTL标签类 -->
    <dependency>
      <groupId>jstl</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>
    <!-- 日志文件管理包 -->
    <!-- log start -->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>${log4j.version}</version>
    </dependency>


    <!-- 格式化对象,方便输出日志 -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>1.1.41</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>
    <!-- log end -->
    <!-- 映入JSON -->
    <dependency>
      <groupId>org.codehaus.jackson</groupId>
      <artifactId>jackson-mapper-asl</artifactId>
      <version>1.9.13</version>
    </dependency>
    <!-- 上传组件包 -->
    <dependency>
      <groupId>commons-fileupload</groupId>
      <artifactId>commons-fileupload</artifactId>
      <version>1.3.1</version>
    </dependency>
    <dependency>
      <groupId>commons-io</groupId>
      <artifactId>commons-io</artifactId>
      <version>2.4</version>
    </dependency>
    <dependency>
      <groupId>commons-codec</groupId>
      <artifactId>commons-codec</artifactId>
      <version>1.9</version>
    </dependency>
  </dependencies>

  <build>
    <resources>
    <!-- maven项目中src源代码下的xml等资源文件编译进classes文件夹, 注意:如果没有这个,它会自动搜索resources下是否有mapper.xml文件, 如果没有就会报org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.pet.mapper.PetMapper.selectByPrimaryKey-->
      <resource>
        <directory>src/main/java</directory>
        <includes>
          <include>**/*.xml</include>
        </includes>
      </resource>
      <!--将resources目录下的配置文件编译进classes文件  -->
      <resource>
        <directory>src/main/resources</directory>
      </resource>
    </resources>
  </build>
</project>

3 构建包结构

我这里把我的包结构都提供出来了,大家可以参考建一下

这里可能会出现的问题,就是右键,new 的时候,没有java class这个选项?

这是因为构建完maven项目的时候,没有把src下的目录标注成可编译的目录,网上找了篇博客,大家参考下,配置一下就可以了 

https://blog.csdn.net/qq_27093465/article/details/52912444

4 使用MyBatis Generator构建代码

推荐的神器,构建代码十分方便,按照下面的地址操作即可,把构建好的代码粘贴过来

https://blog.csdn.net/zhshulin/article/details/23912615

但是这里有个点要注意,就是构建出来的代码,是按照代码生成器的目录层级存放的,我们生成代码之后,要按照自己的目录层级存放,并且把Mapper.xml 里面对应的东西改掉,否则在测试mybatis的时候,会报各种奇葩的错误

这三份文件 UserMaper  User  UserMapper.xml 就是代码生成器生成的,重点要注意的是UserMapper.xml,这里很容易出错,下面用红线标出来的,要特别注意,改成自己对应的路径名称

UserMaper

package com.liuhuxiang.dao;
import com.liuhuxiang.entity.User;
import org.springframework.stereotype.Component;
/**
 * @author liuhuxiang
 * @version $Id: UserMapper.java, v 0.1 2018年04月19日 15:46 liuhuxiang Exp $
 */
@Component
//把UserMapper注册成bean
public interface UserMapper {
    int deleteByPrimaryKey(Integer id);
    int insert(User record);
    int insertSelective(User record);
    User selectByPrimaryKey(Integer id);
    int updateByPrimaryKeySelective(User record);
    int updateByPrimaryKey(User record);
}

User

package com.liuhuxiang.entity;
/**
 * @author liuhuxiang
 * @version $Id: User.java, v 0.1 2018年04月19日 15:44 liuhuxiang Exp $
 */
public class User {
    private Integer id;
    private String userName;
    private String password;
    private Integer age;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName == null ? null : userName.trim();
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password == null ? null : password.trim();
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
}

UserMapper.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.liuhuxiang.dao.UserMapper" >

  <resultMap id="BaseResultMap" type="com.liuhuxiang.entity.User" >
    <id column="id" property="id" jdbcType="INTEGER" />
    <result column="user_name" property="userName" jdbcType="VARCHAR" />
    <result column="password" property="password" jdbcType="VARCHAR" />
    <result column="age" property="age" jdbcType="INTEGER" />
  </resultMap>

  <sql id="Base_Column_List" >
    id, user_name, password, age
  </sql>

  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select 
    <include refid="Base_Column_List" />
    from user_t
    where id = #{id,jdbcType=INTEGER}
  </select>

  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    delete from user_t
    where id = #{id,jdbcType=INTEGER}
  </delete>

  <insert id="insert" parameterType="com.liuhuxiang.entity.User" >
    insert into user_t (id, user_name, password,
      age)
    values (#{id,jdbcType=INTEGER}, #{userName,jdbcType=VARCHAR}, #{password,jdbcType=VARCHAR},
      #{age,jdbcType=INTEGER})
  </insert>

  <insert id="insertSelective" parameterType="com.liuhuxiang.entity.User" >
    insert into user_t
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        id,
      </if>
      <if test="userName != null" >
        user_name,
      </if>
      <if test="password != null" >
        password,
      </if>
      <if test="age != null" >
        age,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        #{id,jdbcType=INTEGER},
      </if>
      <if test="userName != null" >
        #{userName,jdbcType=VARCHAR},
      </if>
      <if test="password != null" >
        #{password,jdbcType=VARCHAR},
      </if>
      <if test="age != null" >
        #{age,jdbcType=INTEGER},
      </if>
    </trim>
  </insert>

  <update id="updateByPrimaryKeySelective" parameterType="com.liuhuxiang.entity.User" >
    update user_t
    <set >
      <if test="userName != null" >
        user_name = #{userName,jdbcType=VARCHAR},
      </if>
      <if test="password != null" >
        password = #{password,jdbcType=VARCHAR},
      </if>
      <if test="age != null" >
        age = #{age,jdbcType=INTEGER},
      </if>
    </set>
    where id = #{id,jdbcType=INTEGER}
  </update>

  <update id="updateByPrimaryKey" parameterType="com.liuhuxiang.entity.User" >
    update user_t
    set user_name = #{userName,jdbcType=VARCHAR},
      password = #{password,jdbcType=VARCHAR},
      age = #{age,jdbcType=INTEGER}
    where id = #{id,jdbcType=INTEGER}
  </update>

</mapper>

5 整合mybats,配置文件

这步主要是配置jdbc.properties   log4j.properties   spring-mybatis.xml三个文件

jdbc.properties

主要是数据库连接的常量设置

# 1 这里一定要注意,看看后面是否有空格,要统一去掉,否则调试会报错
# 2 localhost如果不行的话,可以换成127.0.0.1 试试看,liuhuxiang为数据库名,之前傻乎乎的以为是表名=-=
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/liuhuxiang
username=root
password=admin
#定义初始连接数
initialSize=0
#定义最大连接数
maxActive=20
#定义最大空闲
maxIdle=20
#定义最小空闲
minIdle=1
#定义最长等待时间
maxWait=60000

log4j.properties

主要是日志的配置项,通过apache的开源项目Log4j,可以查看调试过程中的日志,非常好用

#这里大家直接copy就可以了,没有什么要改动的
#定义LOG输出级别
log4j.rootLogger=INFO,Console,File  
#定义日志输出目的地为控制台
log4j.appender.Console=org.apache.log4j.ConsoleAppender  
log4j.appender.Console.Target=System.out  
#可以灵活地指定日志输出格式,下面一行是指定具体的格式
log4j.appender.Console.layout = org.apache.log4j.PatternLayout  
log4j.appender.Console.layout.ConversionPattern=[%c] - %m%n  
#文件大小到达指定尺寸的时候产生一个新的文件
log4j.appender.File = org.apache.log4j.RollingFileAppender  
#指定输出目录
log4j.appender.File.File = logs/ssm.log  
#定义文件最大大小
log4j.appender.File.MaxFileSize = 10MB  
# 输出所以日志,如果换成DEBUG表示输出DEBUG以上级别日志
log4j.appender.File.Threshold = ALL  
log4j.appender.File.layout = org.apache.log4j.PatternLayout  
log4j.appender.File.layout.ConversionPattern =[%p] [%d{yyyy-MM-dd HH\:mm\:ss}][%c]%m%n

spring-mybatis.xml

这也是整合mybatis的关键文件

<?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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
                        http://www.springframework.org/schema/context
                        http://www.springframework.org/schema/context/spring-context-3.1.xsd
                        http://www.springframework.org/schema/mvc
                        http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">
    <!-- 自动扫描 -->
    <!--如果目录层级直接是src/main/java,那么base-package=“**” 就可以了,不过这样命名并不规范,不建议这样做-->
    <context:component-scan base-package="com.liuhuxiang" />
    <!-- 引入配置文件 -->
    <bean id="propertyConfigurer"
          class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="location" value="classpath:jdbc.properties" />
    </bean>

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
          destroy-method="close">
        <!--这里的${driver}..就是引用jdbc.preperties中的常量,能够点过去,说明配置是ok的-->
        <property name="driverClassName" value="${driver}" />
        <property name="url" value="${url}" />
        <property name="username" value="${username}" />
        <property name="password" value="${password}" />
        <!-- 初始化连接大小 -->
        <property name="initialSize" value="${initialSize}"></property>
        <!-- 连接池最大数量 -->
        <property name="maxActive" value="${maxActive}"></property>
        <!-- 连接池最大空闲 -->
        <property name="maxIdle" value="${maxIdle}"></property>
        <!-- 连接池最小空闲 -->
        <property name="minIdle" value="${minIdle}"></property>
        <!-- 获取连接最大等待时间 -->
        <property name="maxWait" value="${maxWait}"></property>
    </bean>

    <!-- spring和MyBatis完美整合,不需要mybatis的配置映射文件 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <!-- 自动扫描mapping.xml文件 -->
        <!--这里有的人写classpath会报错,可以写成classpath* 试试看,小编就是写classpath一直报错,所以加上了*-->
        <property name="mapperLocations" value="classpath*:com/liuhuxiang/mapping/*.xml"></property>
    </bean>

    <!-- DAO接口所在包名,Spring会自动查找其下的类 -->
    <!--建议value中指定的路径,都点点看,看看是不是自己要的路径,不要弄错了-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.liuhuxiang.dao" />
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
    </bean>

    <!-- (事务管理)transaction manager, use JtaTransactionManager for global tx -->
    <bean id="transactionManager"
          class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>

</beans>

6 补全service

UserService

package com.liuhuxiang.service;
import com.liuhuxiang.entity.User;

/**
 * @author liuhuxiang
 * @version $Id: UserService.java, v 0.1 2018年04月19日 15:28 liuhuxiang.
 */
public interface UserService {
    public User getUserById(int userId);
}

UserServiceImpl

package com.liuhuxiang.service;
import com.liuhuxiang.dao.UserMapper;
import com.liuhuxiang.entity.User;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;

/**
 * @author liuhuxiang
 * @version $Id: UserServiceImpl.java, v 0.1 2018年04月19日 15:29 liuhuxiang
 */
@Service("userService")
public class UserServiceImpl implements UserService {
    @Resource
    private UserMapper userMapper;
    @Override
    public User getUserById(int userId) {
        System.out.println("************************userId=" + userId);
        return this.userMapper.selectByPrimaryKey(userId);
    }
}

7 测试

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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="userService" class="com.liuhuxiang.service.UserServiceImpl"/>
</beans>

@RunWith(SpringJUnit4ClassRunner.class)

@ContextConfiguration

这两个标签不明白的,大家参考下面博客

https://blog.csdn.net/u013803262/article/details/52253825

TestMybatis

package src.test.java.testmybatis;
import com.alibaba.fastjson.JSON;
import com.liuhuxiang.entity.User;
import com.liuhuxiang.service.UserService;
import org.apache.log4j.Logger;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import javax.annotation.Resource;

/**
 * @author liuhuxiang
 * @version $Id: TestMybatis.java, v 0.1 2018年04月25日 21:55 liuhuxiang Exp $
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath*:applicationContext.xml", "classpath*:spring-mybatis.xml"})
public class TestMybatis {
    
    private static Logger      logger = Logger.getLogger(TestMybatis.class);
    @Resource
    private        UserService userService;

    @Test
    public void testMyBatis() {
        User user = userService.getUserById(1);
        logger.info(JSON.toJSONString(user));
    }
}

测试结果

表明与mybatis整合成功

8 遇到的问题

mybatis绑定错误  

整合mybatis的过程,遇到的最大的问题,大概就是这个令人头疼的错误吧

大家参考一下这篇博客

https://blog.csdn.net/gwd1154978352/article/details/68954224

小编参照博客修改了很多次,还是报错,我的Mapper.xml文件已经确定没有错误了,查了下,原来是maven打包的问题

maven会把resources下的xml打包成class文件,但是上面的UserMapper.xml并没有放在resources下,而是单独的建了一个包,用来存放这个xml

也就是说,自动打包的时候,不会把这份UserMapper.xml打包到class文件里面,所以解决方法在pom文件中,强制的把xml文件打到class文件中

<build>
  <resources>
    <!-- maven项目中src源代码下的xml等资源文件编译进classes文件夹,
      注意:如果没有这个,它会自动搜索resources下是否有mapper.xml文件,
      如果没有就会报org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.pet.mapper.PetMapper.selectByPrimaryKey-->
    <resource>
      <directory>src/main/java</directory>
      <includes>
        <include>**/*.xml</include>
      </includes>
    </resource>
    <!--将resources目录下的配置文件编译进classes文件  -->
    <resource>
      <directory>src/main/resources</directory>
    </resource>
  </resources>
</build>

问题解决

找不到JDBC连接

我遇到这个问题,是因为下载了最新版本的mysql,去官网找了低版本的mysql,测试成功

参考:https://blog.csdn.net/zhshulin/article/details/37956105

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