jdk LocalDateTime mybatis 空指针解决办法
引入jar包:
-
mysql.mysql-connector-java:5.1.39
-
org.mybatis.mybatis:3.5.2
3. org.mybatis.mybatis-spring:2.0.2
在项目中的mybats升级使用了jdk8的LocalDateTime等后,数据库timesstamp字段有的记录是null,导致查询时出现下面错误
org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.executor.result.ResultMapException: Error attempting to get column 'UPDATE_TIME' from result set. Cause: java.lang.NullPointerException
at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:78)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:440)
at com.sun.proxy.$Proxy154.selectList(Unknown Source)
at org.mybatis.spring.SqlSessionTemplate.selectList(SqlSessionTemplate.java:223)
at org.apache.ibatis.binding.MapperMethod.executeForMany(MapperMethod.java:147)
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:80)
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:57)
at com.sun.proxy.$Proxy181.find(Unknown Source)
at cn.enn.ygego.sunny.sv.service.online.impl.LogisticsBrandServiceImpl.list(LogisticsBrandServiceImpl.java:67)
at cn.enn.ygego.sunny.sv.controller.online.LogisticsBrandController.list(LogisticsBrandController.java:49)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
不能把null转换为LocalDateTime。通过跟踪代码,发现问题出在mysql的驱动上,JDBC42ResultSet的getObject代码如下:
public <T> T getObject(int columnIndex, Class<T> type) throws SQLException {
if (type == null) {
throw SQLError.createSQLException("Type parameter can not be null", "S1009", this.getExceptionInterceptor());
} else if (type.equals(LocalDate.class)) {
return type.cast(this.getDate(columnIndex).toLocalDate());
} else if (type.equals(LocalDateTime.class)) {
return type.cast(this.getTimestamp(columnIndex).toLocalDateTime());
} else if (type.equals(LocalTime.class)) {
return type.cast(this.getTime(columnIndex).toLocalTime());
} else {
if (type.equals(OffsetDateTime.class)) {
try {
return type.cast(OffsetDateTime.parse(this.getString(columnIndex)));
} catch (DateTimeParseException var5) {
}
} else if (type.equals(OffsetTime.class)) {
try {
return type.cast(OffsetTime.parse(this.getString(columnIndex)));
} catch (DateTimeParseException var4) {
}
}
return super.getObject(columnIndex, type);
}
}
return type.cast(this.getTimestamp(columnIndex).toLocalDateTime());代码中this.getTimestamp(columnIndex)返回null,再次执行toLocalDateTime(),当然报错。
解决方式升级mysql驱动,我升级到5.1.47,其他版本没有测试,在5.1.47中代码如下:
public <T> T getObject(int columnIndex, Class<T> type) throws SQLException {
if (type == null) {
throw SQLError.createSQLException("Type parameter can not be null", "S1009", this.getExceptionInterceptor());
} else if (type.equals(LocalDate.class)) {
Date date = this.getDate(columnIndex);
return date == null ? null : type.cast(date.toLocalDate());
} else if (type.equals(LocalDateTime.class)) {
Timestamp timestamp = this.getTimestamp(columnIndex);
return timestamp == null ? null : type.cast(timestamp.toLocalDateTime());
} else if (type.equals(LocalTime.class)) {
Time time = this.getTime(columnIndex);
return time == null ? null : type.cast(time.toLocalTime());
} else {
String string;
if (type.equals(OffsetDateTime.class)) {
try {
string = this.getString(columnIndex);
return string == null ? null : type.cast(OffsetDateTime.parse(string));
} catch (DateTimeParseException var5) {
}
} else if (type.equals(OffsetTime.class)) {
try {
string = this.getString(columnIndex);
return string == null ? null : type.cast(OffsetTime.parse(string));
} catch (DateTimeParseException var4) {
}
}
return super.getObject(columnIndex, type);
}
}