mybatis问题

mybatis配置问题

新建项目

1. 创建一个普通的maven项目

2. 删除src目录 （就可以把此工程当做父工程了，然后创建子工程）

3. 导入maven依赖

   <!--连接数据库-->
       <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
       <dependency>
           <groupId>mysql</groupId>
           <artifactId>mysql-connector-java</artifactId>
           <version>5.1.47</version>
       </dependency>
       <!--mybatis-->
       <dependency>
           <groupId>org.mybatis</groupId>
           <artifactId>mybatis</artifactId>
           <version>3.5.4</version>
       </dependency>
       <!--junit-->
       <dependency>
           <groupId>junit</groupId>
           <artifactId>junit</artifactId>
           <version>4.12</version>
       </dependency>
   

   2.2 创建一个模块

   • 编写mybatis的核心配置文件(一般放在resources下)

   • 创建一个文件，名字后缀为.xml就可以，不用里面的xml配置文件

字符问题

5.7版本

<?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>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?userSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value="123"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com/jirong/dao/UserMapper.xml"/>
    </mappers>
</configuration>

数据库8.0版本

<?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核心配置文件-->
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?userSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
    <!--资源代码注册-->
    <mappers>
        <mapper resource="com/jirong/dao/UserMapper.xml"/>
    </mappers>
</configuration>

5.7的不会报Caused by: org.xml.sax.SAXParseException; lineNumber: 5; columnNumber: 15; 1 字节的 UTF-8 序列的字节 1 无效。

8.0版本会报这个错误

原因

8.0版本出现了中文注释报错了

解决方法

<?xml version="1.0" encoding="UTF-8" ?>
变成<?xml version="1.0" encoding="UTF8" ?>就可以解决

导入资源失败

Caused by: org.apache.ibatis.exceptions.PersistenceException:
Error building SqlSession.
The error may exist in com/jirong/dao/UserMapper1.xml

1.maven自身的问题

解决方法pom.xml中添加如下代码

 <!--在build中配置resources，来防止我们资源导出失败的问题-->
    <build>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

2.文件名字错误，多检查

执行数据操作问题

1.核心配置文件中没有注册资源文件列如：UserMapper.xml

<?xml version="1.0" encoding="UTF8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--namespace=绑定一个指定的Dao/Mapper接口-->
<mapper namespace="com.jirong.dao.UserMapper">
    <select id="getUserList" resultType="com.jirong.pojo.User">
        select * from mybatis.user ;
--         select * from USER
    </select>
</mapper>

注册代码

   <mappers>
        <mapper resource="com/jirong/dao/UserMapper.xml"/>
    </mappers>

2.Invalid bound statement (not found)出现原因和解决方法

org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.jirong.dao.UserMapper.getUserList

可以看这个链接
还没解决可能犯了和本人一样的错

<?xml version="1.0" encoding="UTF8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--namespace=绑定一个指定的Dao/Mapper接口-->
<mapper namespace="com.jirong.dao.UserMapper">
    <select id="getUserList()" resultType="com.jirong.pojo.User">
        select * from mybatis.user ;
--         select * from USER
    </select>
</mapper>

id="getUserList()"给方法调用加上了();