mybatis-扩展

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使用pageHelper参考官方https://github.com/pagehelper/Mybatis-PageHelper/blob/master/wikis/zh/HowToUse.md

 

批处理

• mybatis批处理

修改构建sqlsession对象的方式即可

　　　　SqlSession openSession = sqlSessionFactory.openSession(ExecutorType.BATCH);
        long start = System.currentTimeMillis();
        try{
            EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
            for (int i = 0; i < 10000; i++) {
                mapper.addEmp(new Employee(UUID.randomUUID().toString().substring(0, 5), "b", "1"));
            }
            openSession.commit();
            long end = System.currentTimeMillis();
            //批量：（预编译sql一次==>设置参数===>10000次===>执行（1次））
            //Parameters: 616c1(String), b(String), 1(String)==>4598
            //非批量：（预编译sql=设置参数=执行）==》10000    10200
            System.out.println("执行时长："+(end-start));
        }finally{
            openSession.close();
        }

• 整合spring

需要批处理看这里

　　拿到session之后，按照mybatis批处理的使用方式编码即可

 

调用存储过程

create or replace p_temp_procedure(
　　p_table_name in varchar,p_start in int,p_end in int,p_count out int,p_records out sys_refcursor
) as
begin
     select count(*) into p_count from p_table_name;
　　  open p_records for
　　　　select * from (select rownum rn,t.* from p_table_name t where rownum<=p_end) where rn >=p_start; 

end p_temp_procedure;

 

• statementType="CALLABLE":表示要调用存储过程
• 语法{call procedure_name(params)}；参数里的jdbcType参考JdbcType枚举里的属性

<select id="getPageByProcedure" statementType="CALLABLE" databaseId="oracle">
        {call hello_test(
            #{start,mode=IN,jdbcType=INTEGER},
            #{end,mode=IN,jdbcType=INTEGER},
            #{count,mode=OUT,jdbcType=INTEGER},
            #{emps,mode=OUT,jdbcType=CURSOR,javaType=ResultSet,resultMap=PageEmp}
        )}
</select>

<resultMap type="com.mybatis.bean.Employee" id="PageEmp">
        <id column="EMPLOYEE_ID" property="id"/>
        <result column="LAST_NAME" property="email"/>
        <result column="EMAIL" property="email"/>
</resultMap>

 

自定义类型处理器

mybatis默认枚举类型保存的方式是枚举名称，如果我们要用枚举的其他属性作为存储内容的话，需要自定义typeHandler

实现TypeHandler接口。或者继承BaseTypeHandler

public class MyEnumEmpStatusTypeHandler implements TypeHandler<EmpStatus> {

    /**
     * 定义当前数据如何保存到数据库中
     */
    @Override
    public void setParameter(PreparedStatement ps, int i, EmpStatus parameter,
            JdbcType jdbcType) throws SQLException {
        // TODO Auto-generated method stub
        System.out.println("要保存的状态码："+parameter.getCode());
        ps.setString(i, parameter.getCode().toString());
    }

    @Override
    public EmpStatus getResult(ResultSet rs, String columnName)
            throws SQLException {
        // TODO Auto-generated method stub
        //需要根据从数据库中拿到的枚举的状态码返回一个枚举对象
        int code = rs.getInt(columnName);
        System.out.println("从数据库中获取的状态码："+code);
        EmpStatus status = EmpStatus.getEmpStatusByCode(code);
        return status;
    }

    @Override
    public EmpStatus getResult(ResultSet rs, int columnIndex)
            throws SQLException {
        // TODO Auto-generated method stub
        int code = rs.getInt(columnIndex);
        System.out.println("从数据库中获取的状态码："+code);
        EmpStatus status = EmpStatus.getEmpStatusByCode(code);
        return status;
    }

    @Override
    public EmpStatus getResult(CallableStatement cs, int columnIndex)
            throws SQLException {
        // TODO Auto-generated method stub
        int code = cs.getInt(columnIndex);
        System.out.println("从数据库中获取的状态码："+code);
        EmpStatus status = EmpStatus.getEmpStatusByCode(code);
        return status;
    }

public enum EmpStatus {
    LOGIN(100,"用户登录"),LOGOUT(200,"用户登出"),REMOVE(300,"用户不存在");
    
    
    private Integer code;
    private String msg;
    private EmpStatus(Integer code,String msg){
        this.code = code;
        this.msg = msg;
    }
    public Integer getCode() {
        return code;
    }
    
    public void setCode(Integer code) {
        this.code = code;
    }
    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }
    
    //按照状态码返回枚举对象
    public static EmpStatus getEmpStatusByCode(Integer code){
        switch (code) {
            case 100:
                return LOGIN;
            case 200:
                return LOGOUT;    
            case 300:
                return REMOVE;
            default:
                return LOGOUT;
        }
    }

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