概要
- 問題描述
我想用枚舉類來表示用戶當前狀態,枚舉類由 code
和 msg
組成,但我只想把 code
保存到數據庫,查詢處理,能知道用戶當前狀態,這應該怎麼做呢?在 Spring
整合MyBatis
的時候,我們有一個MyBatis的配置文件,我們可以用下面的標籤樣式指定
<typeHandlers>
<typeHandler handler="com.xxx.XxxTypeHandler" javaType="com.xxx.XxxEnum"/>
</typeHandlers>
那 Spring Boot
整合 MyBatis
呢?
- 解決方案
MyBatis爲我們提供瞭解決方案:你可以集成 BaseTypeHandler
,或者實現 TypeHandler
。我們需要在應用配置文件中指定handler的路徑
type-handlers-package: com.xxx.handlers
另外,我們需要在Handler上添加註解,指明枚舉類(enum)。
枚舉類
package com.fengwenyi.learn.java.mybatisenum;
/**
* @author Wenyi Feng
*/
public enum Status {
LOGIN(100, "在線"),
LOGOUT(200, "不在線")
;
private Integer code;
private String msg;
Status(Integer code, String msg) {
this.code = code;
this.msg = msg;
}
/**
* 通過 code 獲取 Status
* @param code
* @return
*/
public static Status getStatusByCode(Integer code) {
switch (code) {
case 100:
return LOGIN;
case 200:
return LOGOUT;
default:
return LOGOUT;
}
}
// getter
}
TypeHandler
package com.fengwenyi.learn.java.mybatisenum.handlers;
import com.fengwenyi.learn.java.mybatisenum.Status;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.MappedTypes;
import org.apache.ibatis.type.TypeHandler;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* @author Wenyi Feng
*/
@MappedTypes({Status.class})
public class UserStatusTypeHandler implements TypeHandler<Status> {
@Override
public void setParameter(PreparedStatement preparedStatement, int i, Status status, JdbcType jdbcType) throws SQLException {
preparedStatement.setInt(i, status.getCode());
}
@Override
public Status getResult(ResultSet resultSet, String s) throws SQLException {
Integer code = resultSet.getInt(s);
return Status.getStatusByCode(code);
}
@Override
public Status getResult(ResultSet resultSet, int i) throws SQLException {
Integer code = resultSet.getInt(i);
return Status.getStatusByCode(code);
}
@Override
public Status getResult(CallableStatement callableStatement, int i) throws SQLException {
Integer code = callableStatement.getInt(i);
return Status.getStatusByCode(code);
}
}
application.yml
spring:
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/learn
username: root
password: xfsy2018
mybatis:
type-aliases-package: com.fengwenyi.learn.java.mybatisenum.model
mapper-locations: classpath:mapper/*.xml
configuration:
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
type-handlers-package: com.fengwenyi.learn.java.mybatisenum.handlers
測試
@Autowired
private IUserService userService;
@Test
public void contextLoads() {
// find();
insert();
}
private void insert() {
UserModel model = new UserModel();
model.setStatus(Status.LOGIN);
boolean rs = userService.save(model);
System.out.println(rs);
}
private void find() {
List<UserModel> modelList = userService.findAll();
for (UserModel model : modelList) {
System.out.println(model.toString());
}
}
數據
測試代碼
https://github.com/fengwenyi/JavaLearnProject/tree/master/mybatis-enum