MyBatis Custom type converter __mybatis

There is such a need :

There is a Boolean field that needs to be saved to the database, but the database does not support the Boolean type, so a single character (char (1)) is used to store the Boolean value, and a Boolean type is still used in the JavaBean.

We use MyBatis as the persistence layer framework, but there is a problem, the database is a char, and the program is a Boolean, how to implement data type automatic conversion.

Solution :

MyBatis provides support for custom type converters (Typehandler), so we can write our own type converters to implement this automatic conversion function.

implementation Steps :

The first step: writing a custom type converter

  Java code   /**   *    */   package  test.atfm.persistence.mybatis.handler;      import java.sql.callablestatement;    import java.sql.preparedstatement;   import java.sql.resultset;   Import  java.sql.SQLException;      import org.apache.ibatis.type.jdbctype;   import org.apache.ibatis.type.typehandler;     /**   *  @author     Conversion between chars in Boolean and JDBC in  * java;true-y;false-n   */   public class  BooleanTypeHandler implements TypeHandler {           /*  (non-javadoc)        *  @see   Org.apache.ibatis.type.typehandler#getresult (java.sql.resultset, java.lang.string)         */        @Override &Nbsp;      public object getresult (resultset arg0, string arg1 )  throws SQLException {           String  Str = arg0.getstring (arg1);           Boolean  rt = boolean.false;           if  ( Str.equalsignorecase ("Y") {                rt = Boolean.TRUE;           }           return rt;        }           /*  (non-javadoc)        *   @see  org.apache.ibatis.type.typehandler#getresult (java.sql.callablestatement, int)         */        @Override        public Object  GetResult (CALLABLESTATEMENT ARG0, INT ARG1)                 throws SQLException {            boolean b = arg0.getboolean (arg1);            return b == true ?  "Y"  :  "N";        }          /*  (non-javadoc)         *  @see  org.apache.ibatis.type.typehandler#setparameter (java.sql.preparedstatement,  Int, java.lang.object, org.apache.ibatis.type.jdbctype)        */         @Override        public void setparameter ( preparedstatement arg0, int arg1, object arg2,                JDBCTYPE ARG3)  throws SQLException {            Boolean b =  (Boolean)  arg2;            String value =  (Boolean)  b == true ?   "Y"  :  "N";           arg0.setstring (Arg1,  value);       }  }    

Step Two: Register the type converter

XML code <?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" > &       lt;configuration> <properties resource= "db.properties" ></properties> <typeHandlers> <strong><span style= "color: #ff0000;" ><typehandler javatype= "Boolean" jdbctype= "CHAR" handler= "Test.atfm.persistence.mybatis.handler.BooleanTyp Ehandler "/></span></