通过ibatis的blob 存储java的hashmap

 这几天测试blob获取和存储的时候,被卡了很久,最后才发现是占用了关键字导致无法获取结果,血的教训啊.
以后起名字要用最恶心的,不要用最方便的了.闲话少说,java的hashmap是不能直接存储到数据库中的.
本地数据库为mysql,里面有blob的类型可供使用.方法也很简单,上代码
数据库建表

CREATE TABLE `test` ( `id` varchar(32) NOT NULL, `fieldarr` blob, PRIMARY KEY (`id`) USING BTREE ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Java类

public class Test implements Serializable{ private String id; private byte[] fields; public String getId(){ return id; } public void setId(String id){ this.id = id; } public byte[] getFields(){ return fields; } public void setFields(byte[] fields){ this.fields = fields; } }

然后配置ibatis

<?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 namespace="Test"> <!-- Use type aliases to avoid typing the full classname every time. --> <typeAlias alias="Test" type="bruce.Test"/> <resultMap id="FieldResult" class="Test"> <result property="id" column="ID"/> <result property="fields" column="FIELDARR" jdbcType="BLOB" /> </resultMap> <select id="selectTestByid" parameterClass="string" resultMap="FieldResult"> <!--[CDATA[ select * from test where ID = #value# ]]> </select> <update id="updateTest" parameterClass="Test"> <![CDATA[ update test set FIELDARR = #fields# where ID = #id# ]]--> </update> </sqlMap>

dao正常写就可以

public List<Test> selectTestByid(String id) throws SQLException { return sqlMapper.queryForList("selectTestByid", id); } public void updateTest(Test t) throws SQLException { sqlMapper.update("updateTest", t); }

如此可以顺利存取byte了,这离目标hashmap还差一点.修改Test类

public class Test implements Serializable{ private String id; private byte[] fields; private HashMap fieldMap; public String getId(){ return id; } public void setId(String id){ this.id = id; } public byte[] getFields(){ try { ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(bos); oos.writeObject(fieldMap); fields=bos.toByteArray(); bos.flush(); oos.close(); bos.close(); } catch (IOException e) { } return fields; } public void setFields(byte[] fields){ this.fields = fields; try{ ByteArrayInputStream bais = new ByteArrayInputStream(fields); ObjectInputStream obis = new ObjectInputStream(bais); fieldMap = (HashMap<String, FieldDesc>)obis.readObject(); obis.close(); bais.close(); } catch (IOException e) { } catch (ClassNotFoundException e) { } } public HashMap getFieldMap(){ if(fieldMap==null) fieldMap = new HashMap(); return fieldMap; } }

stream的关闭写的不是很好,凑合用了.