mybatis enum枚举 typeHandle
虽然mysql提供了enum类型，但有些情况下并不推荐直接使用。可以通过typeHandle将java中的枚举类型进行转换后存储到mysql
例如枚举 Delete
public enum Delete {
NO(1, "没删除"),
YES(2, "已删除");
private Integer code;
private String describe;
public Integer getCode() {
return code;
}
public String getDescribe() {
return describe;
}
Delete(Integer code, String describe) {
this.code = code;
this.describe = describe;
}
public static Delete getDeleteFromCode(int code) {
for (Delete delete : Delete.values()) {
if (delete.getCode() == code) {
return delete;
}
}
return null;
}
public static Delete getDeleteFromDescribe(String describe) {
for (Delete delete : Delete.values()) {
if (delete.getDescribe() == describe) {
return delete;
}
}
return null;
}
}对于Delete这个枚举类型，在进行存储的时候可有四种选择
a.存name，此例中是 no yes
b.存序号，此例中是 0,1
c.存code，此例中是1,2
d.存describe,此例中是 没删除，已删除
mybatis对枚举类型有两种类型支持 EnumTypeHandler和EnumOrdinalTypeHandler。
其中EnumTypeHandler为默认的，存储枚举的name值(此例对应的是"NO,YES")，而EnumOrdinalTypeHandler存储的是枚举的序号 此处“NO”对应的序号是“0”，“YES”对应的序号是“1”;
ab两种情况mybatis已经做出了支持，而cd两种情况就需要我们自定义实现TypeHandler类。具体操作代码如下：
建表语句
CREATE TABLE `test_table` (
`id` int(11) NOT NULL,
`deleteStatusA` varchar(11) DEFAULT '0',
`deleteStatusB` int(11) DEFAULT NULL,
`deleteStatusC` int(11) DEFAULT NULL,
`deleteStatusD` varchar(11) DEFAULT NULL,
`createTime` datetime DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`updateTime` timestamp NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=utf8实体类
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Table;
@Table(name = "test_table")
public class TestTable {
@Column(name = "id")
private Integer id;
private Delete delete;
@Column(name = "createTime")
private Date createtime;
@Column(name = "updateTime")
private Date updatetime;
/**
* @return ID
*/
public Integer getId() {
return id;
}
/**
* @param id
*/
public void setId(Integer id) {
this.id = id;
}
/**
* @return delete
*/
public Delete getDelete() {
return delete;
}
/**
* @param delete
*/
public void setDelete(Delete delete) {
this.delete = delete;
}
/**
* @return createTime
*/
public Date getCreatetime() {
return createtime;
}
/**
* @param createtime
*/
public void setCreatetime(Date createtime) {
this.createtime = createtime;
}
/**
* @return updateTime
*/
public Date getUpdatetime() {
return updatetime;
}
/**
* @param updatetime
*/
public void setUpdatetime(Date updatetime) {
this.updatetime = updatetime;
}
}mybatis配置文件
INSERT INTO test_table ( id,deleteStatusA)
values(#{id} ,#{delete})
INSERT INTO test_table ( id,deleteStatusB)
values(#{id} ,#{delete, typeHandler=org.apache.ibatis.type.EnumOrdinalTypeHandler})
INSERT INTO test_table ( id,deleteStatusC)
values(#{id} ,#{delete, typeHandler=com.hstao.typeHandle.DeleteCodeTypeHandle})
INSERT INTO test_table ( id,deleteStatusD)
values(#{id} ,#{delete, typeHandler=com.hstao.typeHandle.DeleteDescribeTypeHandle})
自定义的DeleteCodeTypeHandle
/**
* 描述: DeleteCodeTypeHandle
*
* @author hstao
* @create 2019-05-07 10:05
*/
public class DeleteCodeTypeHandle implements TypeHandler {
@Override
public void setParameter(PreparedStatement preparedStatement, int i, Delete delete, JdbcType jdbcType)
throws SQLException {
preparedStatement.setInt(i,delete.getCode());
}
@Override
public Delete getResult(ResultSet resultSet, String s) throws SQLException {
return Delete.getDeleteFromCode(resultSet.getInt(s));
}
@Override
public Delete getResult(ResultSet resultSet, int i) throws SQLException {
return Delete.getDeleteFromCode(resultSet.getInt(i));
}
@Override
public Delete getResult(CallableStatement callableStatement, int i) throws SQLException {
return Delete.getDeleteFromCode(callableStatement.getInt(i));
}
} 自定义的DeleteDescribeTypeHandle
/**
* 描述: DeleteDescribeTypeHandle
*
* @author hstao
* @create 2019-05-07 10:15
*/
public class DeleteDescribeTypeHandle implements TypeHandler {
@Override
public void setParameter(PreparedStatement preparedStatement, int i, Delete delete, JdbcType jdbcType)
throws SQLException {
preparedStatement.setString(i,delete.getDescribe());
}
@Override
public Delete getResult(ResultSet resultSet, String s) throws SQLException {
return Delete.getDeleteFromDescribe(resultSet.getString(s));
}
@Override
public Delete getResult(ResultSet resultSet, int i) throws SQLException {
return Delete.getDeleteFromDescribe(resultSet.getString(i));
}
@Override
public Delete getResult(CallableStatement callableStatement, int i) throws SQLException {
return Delete.getDeleteFromDescribe(callableStatement.getString(i));
}
} 测试调用：
/**
* 描述: TestTableManager
*
* @author hstao
* @create 2019-05-06 16:36
*/
@Component
public class TestTableManager implements TestTableManagerI {
@Resource
private TestTableMapper testTableMapper;
@Override
public void insert(){
TestTable testTable=new TestTable();
testTable.setId(100);
testTable.setDelete(Delete.YES);
testTableMapper.insertDataA(testTable);
testTableMapper.insertDataB(testTable);
testTableMapper.insertDataC(testTable);
testTableMapper.insertDataD(testTable);
}
}执行此处的insert方法，分别对应Delete的四种存储场景；
结果如下：
可以看到对于同一条数据，对于abcd四种不同场景，在mysql中最终存储的值不一样，根据业务需要，可以选择不同的类型，同时用java的enum来替代mysql的enum，代码可读性，封装也比较好