浅谈mybatismapper.xml文件中$和＃的区别

 
  select * from user where username like CONCAT(CONCAT('%', #{name}), '%')
 

 
  select * from user where username like '%${value}%'
 

package com.weather.weatherexpert.common.utils; 
 
/**
 * 
Title: 
 * 
Description: 
 *
 * @Author 
 * @CreateTime 
 */
public enum City {
 
  XINZHOU(100002,"忻州"),
  DATONG(100003,"大同"),
  TAIYUAN(100001,"太原");
 
  private final Integer code;
  private final String name;
 
 
  City(Integer value, String desc) {
    this.code = value;
    this.name = desc;
  }
 
  public Integer getCode() {
    return code;
  }
 
  public String getName() {
    return name;
  }
}

 area_table
 
 
where 1=1

 and city_name=#{cityName}
 

package com.weather.weatherexpert.common.utils;
 
/**
 * 
Title: 
 * 
Description: 
 *
 * @Author
 * @CreateTime
 */
public class CityClass {
 
  public static enum CityEnum {
 
    XINZHOU(100002, "忻州"),
    DATONG(100003, "大同"),
    TAIYUAN(100001, "太原");
 
    private final Integer code;
    private final String name; 
 
    CityEnum(Integer value, String desc) {
      this.code = value;
      this.name = desc;
    }
 
    public Integer getCode() {
      return code;
    }
 
    public String getName() {
      return name;
    }
  }
}

/*   Caused by: org.apache.ibatis.builder.BuilderException: Error evaluating expression
    'cityName == @com.weather.weatherexpert.common.utils.CityClass@CityEnum.XINZHOU.getName'. Cause: org.apache.ibatis.ognl.OgnlException:
    Could not get static field CityEnum from class com.weather.weatherexpert.common.utils.CityClass [java.lang.NoSuchFieldException: CityEnum]*/
    
      area_table