Mybatis报错解决[不定时更新]

1、jdbcType=“int"和jdbcType=”_int"的区别

<resultMap id="Application" type="org.bean.Application">
        <constructor>
            <idArg column="id" javaType="_int"/>
            <arg column="project_id" javaType="_int"/>
            <arg column="name" javaType="string"/>
            <arg column="description" javaType="string"/>
            <arg column="deleted" javaType="_int"/>
        </constructor>
</resultMap>

public class Application {
    private int id;
    private int projectId;
    private String name;
    private int deleted;

    public Application(int id, int projectId, String name, String description, int deleted) {
        this.id = id;
        this.projectId = projectId;
        this.name = name;
        this.description = description;
        this.deleted = deleted;
    }
}

上面代码中mybatis的jdbcType=“int"须和Application中Integer类型对应，jdbcType=”_int"需和Application中int类型对应，任何一方不对应都会报java.lang.NoSuchMethodException: com.common.bean.Application.(int, int, java.lang.String, java.lang.String, int)错误。

2、报错：
The error may involve defaultParameterMap.
The error occurred while setting parameters.
com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure.
解决：我出现的原因是在写mybatis的mapper文件时在sql语句后面用/**/写了注释，删掉就好了。
原来：<select id="retrieveAll" resultMap="Event"> select * from event_definition /*where type='HD'*/ </select>
改成：<select id="retrieveAll" resultMap="Event"> select * from event_definition </select>就成功了。
还有一个解决方案，我在网上找到的，将jdbc:mysql://127.0.0.1:3306/hr?useUnicode=true&characterEncoding=UTF-8&useSSL=false中的useSSL=false配置去掉也能成功。
注：我用的mysql是8.0.11版本，mybatis是3.5.0版本。