How to convert java.util.Date, java.sql.Date, LocalDate, ZonedDateTime

Purpose

LocalDate has been added to Java8, which is very convenient. However, java.sql.Date is used when using JDBC, and java.util.Date is used when using POI, but interoperability is not considered in LocalDate. So, for the three that are often used in business, ZonedDateTime also summarized the conversion methods to facilitate interoperability.

Each conversion method

• java.sql.Date→LocalDate

sqlDate, utilDate and LocalDate.java

public LocalDate convertToLocalDate(java.sql.Date sqlDate){
	return sqlDate.toLocalDate();
}

• java.sql.Date→java.util.Date

sqlDate, utilDate and LocalDate.java

public java.util.Date convertToUtilDate(java.sql.Date sqlDate){
	return sqlDate;
}

• java.util.Date→LocalDate

sqlDate, utilDate and LocalDate.java

public LocalDate convertToLocalDate(java.util.Date utilDate){
	return utilDate.toInstant().atZone(ZoneId.systemDefault()).toLocalDate();
}

• java.util.Date→java.sql.Date

sqlDate, utilDate and LocalDate.java

public java.sql.Date convertToSqlDate(java.util.Date utilDate){
	return new java.sql.Date(utilDate.getTime());
}

• LocalDate→java.util.Date

sqlDate, utilDate and LocalDate.java

public java.util.Date convertToUtilDate(LocalDate localDate){
	 return java.util.Date.from(localDate.atStartOfDay().atZone(ZoneId.systemDefault()).toInstant());
}

• LocalDate→java.sql.Date

sqlDate, utilDate and LocalDate.java

public java.sql.Date convertToSqlDate(LocalDate localDate){
	return java.sql.Date.valueOf(localDate);
}

• java.util.Date→ZonedDateTime

sqlDate, utilDate and LocalDate.java

public ZonedDateTime convertToZonedDateTime(java.util.Date utilDate){
	return utilDate.toInstant().atZone(ZoneId.systemDefault());
}

• java.sql.Date→ZonedDateTime

sqlDate, utilDate and LocalDate.java

public ZonedDateTime convertToZonedDateTime(java.sql.Date sqlDate){
	return sqlDate.toLocalDate().atStartOfDay(ZoneId.systemDefault());
}

• LocalDate→ZonedDateTime

sqlDate, utilDate and LocalDate.java

public ZonedDateTime convertToZonedDateTime(LocalDate localDate){
	return localDate.atStartOfDay(ZoneId.systemDefault());
}

• ZonedDateTime→java.util.Date

sqlDate, utilDate and LocalDate.java

public java.util.Date convertToUtilDate(ZonedDateTime zonedDateTime){
	return java.util.Date.from(zonedDateTime.toInstant());
}

• ZonedDateTime→java.sql.Date

sqlDate, utilDate and LocalDate.java

public java.sql.Date convertToSqlDate(ZonedDateTime zonedDateTime){
	return java.sql.Date.valueOf(zonedDateTime.toLocalDate());
}

• ZonedDateTime→LocalDate

sqlDate, utilDate and LocalDate.java

public LocalDate convertToLocalDate(ZonedDateTime zonedDateTime){
	return zonedDateTime.toLocalDate();
}

Summary

The conversion method of java.util.Date, java.sql.Date, LocalDate, ZonedDateTime is summarized. The source, including the tests, can be found here [https://github.com/xaatw0/quiita/blob/master/src/sqlDate, utilDate and LocalDate.java).