mybatis 自定义传入参数类型(TypeHandler)

mybatis 自定义传入参数类型(TypeHandler)
关于处理model中list属性，要将list中的值转化为string存储到数据库中, java:List 数据库：varchar

Model中的属性是
private List protectedList;
Mysql数据库存储为：varchar（2000）

在自定义的typeHandler中定义方法
public class ListTypeHandler implements TypeHandler<List> {

@Override
public List<ProtectedBO> getResult(ResultSet rs, String column) throws SQLException {
	String protectedListValue = rs.getString(column);
	return protectedListValue == null ? null
			: new Gson().fromJson(protectedListValue, new TypeToken<List<ProtectedBO>>() {
			}.getType());
}

@Override
public List<ProtectedBO> getResult(ResultSet rs, int index) throws SQLException {
	String protectedListValue = rs.getString(index);
	return protectedListValue == null ? null
			: new Gson().fromJson(protectedListValue, new TypeToken<List<ProtectedBO>>() {
			}.getType());
}

@Override
public List<ProtectedBO> getResult(CallableStatement cs, int index) throws SQLException {
	String protectedListValue = cs.getString(index);
	return protectedListValue == null ? null
			: new Gson().fromJson(protectedListValue, new TypeToken<List<ProtectedBO>>() {
			}.getType());
}

@Override
public void setParameter(PreparedStatement ps, int index, List<ProtectedBO> protectedList, JdbcType jdbcType)
		throws SQLException {
	if (null == protectedList || protectedList.size() == 0 || protectedList.isEmpty()) {
		ps.setNull(index, Types.VARCHAR);
	} else {
		ps.setString(index, new Gson().toJson(protectedList));
	}
}

mybatis mapper.xml的添加或者编辑方法

mybatis-config.xml中加入如下的代码声明自定义handler