ibatis-TypeHandlerCallback使用

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场景

数据入库前需要加密，替换特殊字符，枚举类型转化；数据读取时需要对数值字段null保护等。。

应用实例

1.字段加密入库，解密读取

public class EncodeTypeHandler implements TypeHandlerCallback {    @Override    public void setParameter(ParameterSetter parameterSetter, Object o) throws SQLException {        String id = encode((String) o);        parameterSetter.setString(id);    }    @Override    public Object getResult(ResultGetter resultGetter) throws SQLException {        return decode(resultGetter.getString());    }    @Override    public Object valueOf(String s) {        return s;    }}

2.字段特殊字符处理（替换’\0’）

public class SpecialCharTypeHandler implements TypeHandlerCallback {    @Override    public void setParameter(ParameterSetter parameterSetter, Object o) throws SQLException {        if (o == null) {            parameterSetter.setString(null);            return;        }        String id = (String)o;        parameterSetter.setString(id.replaceAll("\0", ""));    }    @Override    public Object getResult(ResultGetter resultGetter) throws SQLException {        return resultGetter.getString();    }    @Override    public Object valueOf(String s) {        return s;    }}

3.字段保护（防止数据库里的值是null）

public class IntegerTypeHandler implements TypeHandlerCallback {    @Override    public Object getResult(ResultGetter getter) throws SQLException {        if (getter.wasNull()) {            return 0;        }        return getter.getInt();    }    @Override    public void setParameter(ParameterSetter setter, Object parameter)            throws SQLException {        setter.setInt((Integer)parameter);    }    @Override    public Object valueOf(String s) {        return s;    }}

4.枚举类型转化

public class OrderStatusTypeHandler implements TypeHandlerCallback {    @Override    public void setParameter(ParameterSetter parameterSetter, Object o) throws SQLException {        if(o==null)            o = OrderStatus.Init;        int b = ((OrderStatus) o).getCode();        parameterSetter.setInt(b);    }    @Override    public Object getResult(ResultGetter resultGetter) throws SQLException {        if (resultGetter.wasNull())            return null;        int code = resultGetter.getInt();        OrderStatus orderStatus = null;        orderStatus = OrderStatus.getOrderStatus(code);        return orderStatus;    }    @Override    public Object valueOf(String s) {        return s;    }}

配置

在sqlMapConfig或者在sqlMap都可以配置

- 配置别名使用
1.在sqlMapConfig里配置：

<sqlMapConfig>   <settings enhancementEnabled="true" lazyLoadingEnabled="false" cacheModelsEnabled="false"               useStatementNamespaces="false" maxRequests="32" maxSessions="10" maxTransactions="5"/>   <typeAlias alias="SpecialCharTypeHandler" type="com.mo.SpecialCharTypeHandler"/>   <sqlMap resource="sqlmap/PayOrderDao.xml"/></sqlMapConfig>

2.在sqlMap（PayOrderDao.xml）里配置

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"        "http://ibatis.apache.org/dtd/sql-map-2.dtd"><sqlMap>    <typeAlias alias="SpecialCharTypeHandler" type="com.mo.SpecialCharTypeHandler"/>    ...</sqlMap>

根据参数类型匹配使用
1.在sqlMapConfig里配置：

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE sqlMapConfig PUBLIC "-//ibatis.apache.org//DTD SQL Map Config 2.0//EN"        "http://ibatis.apache.org/dtd/sql-map-config-2.dtd"><sqlMapConfig>    <settings enhancementEnabled="true" lazyLoadingEnabled="false" cacheModelsEnabled="true"              useStatementNamespaces="false" maxRequests="32" maxSessions="10" maxTransactions="5"/>    <typeHandler javaType="com.mo.OrderStatus" callback="com.mo.OrderStatusTypeHandler"/>    <sqlMap resource="sqlmap/PayOrderDao.xml"/></sqlMapConfig>

2.在sqlMap（PayOrderDao.xml）里配置

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"        "http://ibatis.apache.org/dtd/sql-map-2.dtd"><sqlMap>    <typeHandler javaType="com.OrderStatus" callback="com.mo.OrderStatusTypeHandler"/>    ...</sqlMap>

使用

别名配置

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"        "http://ibatis.apache.org/dtd/sql-map-2.dtd"><sqlMap>    <typeAlias alias="OrderStatusTypeHandler" type="com.mo.OrderStatusTypeHandler"/>    ..    <update id="updatePayStatus">        update  tbl_pay_order        set         order_status=#orderStatus,handler=OrderStatusTypeHandler#,         where id=#id#;    </update>    ..</sqlMap>

参数类型匹配（不需要指定handler）

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"        "http://ibatis.apache.org/dtd/sql-map-2.dtd"><sqlMap>    <typeHandler javaType="com.mo.OrderStatus" callback="com.mo.OrderStatusTypeHandler"/>    ..    <update id="updatePayStatus">        update  tbl_pay_order        set         order_status=#orderStatus#,         where id=#id#;    </update>    ..</sqlMap>

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