Java8新增时间类LocalDateTime、LocalDate、LocalTime，以及在Spring中作为参数入参
线程安全
以前我们习惯用的Date时间类是可变类，在多线程环境下操作时需要保证线程安全、而LocalDateTime、LocalDate、LocalTime类是不可变类，并且是线程安全的。
在日期格式化选择上Date使用的SimpleDateFormat本身也是线程不安全的，而现在取而代之的是DateTimeFormatter类，是线程安全的。
查看源码比较
LocalDateTime
DateTimeFormatter
SimpleDateFormat
LocalDateTime、LocalDate、LocalTime使用
获取当前时刻
LocalDateTime localDateTime = LocalDateTime.now();
System.out.println("表示当前时间："+localDateTime);
System.out.println("表示当前年份："+localDateTime.getYear());
System.out.println("表示当前月份："+localDateTime.getMonth());
System.out.println("表示当前月份："+localDateTime.getMonthValue());
System.out.println("表示当天日期："+localDateTime.getDayOfMonth());
System.out.println("表示当前时："+localDateTime.getHour());
System.out.println("表示当前分："+localDateTime.getMinute());
System.out.println("表示当前秒："+localDateTime.getSecond());
System.out.println("表示当前星期几："+localDateTime.getDayOfWeek());
System.out.println("表示当前是一年中的第几天："+localDateTime.getDayOfYear());
System.out.println("表示当前纳秒数："+localDateTime.getNano());
LocalDate、LocalTime方法同上
构造时间：指定年月日时分秒
LocalDateTime dateTime = LocalDateTime.of(2020, 2, 15, 06, 25, 45);
LocalDateTime dateTime1 = LocalDateTime.of(2020, Month.FEBRUARY, 15, 06, 25, 45);
System.out.println("构造日期2020-02-15 06:25:45"+dateTime);
System.out.println("构造日期2020-02-15 06:25:45"+dateTime1);
修改日期
LocalDateTime dateTime = LocalDateTime.now();
System.out.println("减少两年"+dateTime.minusYears(2));
System.out.println("减少两天"+dateTime.minusDays(2));
System.out.println("增加两年"+dateTime.plusYears(2));
System.out.println("增加两天"+dateTime.plusDays(2));
System.out.println("修改年份到2019"+dateTime.withYear(2019));
System.out.println("修改月份到3月"+dateTime.withMonth(3));
日期格式化
LocalDateTime dateTime = LocalDateTime.now();
System.out.println("格式化日期"+dateTime.format(DateTimeFormatter.ISO_DATE));
System.out.println("格式化日期"+dateTime.format(DateTimeFormatter.BASIC_ISO_DATE));
System.out.println("格式化日期"+dateTime.format(DateTimeFormatter.ofPattern("yyyy/MM/dd")));
输出结果
格式化日期2020-02-15
格式化日期20200215
格式化日期2020/02/15
时间反解析
LocalDateTime parse = LocalDateTime.parse("2020-02-15 06:42:34", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
System.out.println("时间反解析"+parse);
时间计算
LocalDate localDate = LocalDate.now();
System.out.println("本月第一天"+localDate.with(TemporalAdjusters.firstDayOfMonth()));
System.out.println("本月最后一天"+localDate.with(TemporalAdjusters.lastDayOfMonth()));
System.out.println("取2020年1月第一个周一"+LocalDate.parse("2020-01-01").with(TemporalAdjusters.firstInMonth(DayOfWeek.MONDAY)));
其他常用方法
LocalDateTime dateTime1 = LocalDateTime.of(2020, 2, 15, 06, 25, 45);
LocalDateTime dateTime = LocalDateTime.now();
System.out.println("判断LocalDateTime是否在指定LocalDateTime之后"+dateTime1.isAfter(dateTime));
System.out.println("时间反解析判断LocalDateTime是否在指定LocalDateTime之前"+dateTime1.isBefore(dateTime));
System.out.println("判断LocalDateTime是否在指定LocalDateTime相等"+dateTime1.isEqual(dateTime));
System.out.println("返回LocalDateTime的LocalDate部分"+dateTime.toLocalDate());
System.out.println("返回LocalDateTime的LocalTime部分"+dateTime.toLocalTime());
System.out.println("返回LocalDateTime的字符串表示 "+dateTime.toString());
当LocalDateTime、LocalDate、LocalTime作为RequestParam或者PathVariable时，使用Converter转换，如果以Json形式传入时，使用Jackson的json序列化和反序列化来转换。
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalTimeSerializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.convert.converter.Converter;
import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
import java.util.Date;
/**
* @author yly
* @ClassName DateConfig
* @Date 2020/2/15 7:59
* @Version 1.0
**/
@Configuration
public class DateConfig {
/**
* 默认日期时间格式
*/
public static final String DEFAULT_DATE_TIME_FORMAT = "yyyy-MM-dd HH:mm:ss";
/**
* 默认日期格式
*/
public static final String DEFAULT_DATE_FORMAT = "yyyy-MM-dd";
/**
* 默认时间格式
*/
public static final String DEFAULT_TIME_FORMAT = "HH:mm:ss";
/**
* LocalDate转换器，用于转换RequestParam和PathVariable参数
*/
@Bean
public Converter<String, LocalDate> localDateConverter() {
return new Converter<String, LocalDate>() {
@Override
public LocalDate convert(String source) {
return LocalDate.parse(source, DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT));
}
};
}
/**
* LocalDateTime转换器，用于转换RequestParam和PathVariable参数
*/
@Bean
public Converter<String, LocalDateTime> localDateTimeConverter() {
return new Converter<String, LocalDateTime>() {
@Override
public LocalDateTime convert(String source) {
return LocalDateTime.parse(source, DateTimeFormatter.ofPattern(DEFAULT_DATE_TIME_FORMAT));
}
};
}
/**
* LocalTime转换器，用于转换RequestParam和PathVariable参数
*/
@Bean
public Converter<String, LocalTime> localTimeConverter() {
return new Converter<String, LocalTime>() {
@Override
public LocalTime convert(String source) {
return LocalTime.parse(source, DateTimeFormatter.ofPattern(DEFAULT_TIME_FORMAT));
}
};
}
/**
* Date转换器，用于转换RequestParam和PathVariable参数
*/
@Bean
public Converter<String, Date> dateConverter() {
return new Converter<String, Date>() {
@Override
public Date convert(String source) {
SimpleDateFormat format = new SimpleDateFormat(DEFAULT_DATE_TIME_FORMAT);
try {
return format.parse(source);
} catch (ParseException e) {
throw new RuntimeException(e);
}
}
};
}
/**
* Json序列化和反序列化转换器，用于转换Post请求体中的json以及将我们的对象序列化为返回响应的json
*/
@Bean
public ObjectMapper objectMapper(){
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
objectMapper.disable(DeserializationFeature.ADJUST_DATES_TO_CONTEXT_TIME_ZONE);
//LocalDateTime系列序列化和反序列化模块，继承自jsr310，我们在这里修改了日期格式
JavaTimeModule javaTimeModule = new JavaTimeModule();
javaTimeModule.addSerializer(LocalDateTime.class,new LocalDateTimeSerializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_TIME_FORMAT)));
javaTimeModule.addSerializer(LocalDate.class,new LocalDateSerializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT)));
javaTimeModule.addSerializer(LocalTime.class,new LocalTimeSerializer(DateTimeFormatter.ofPattern(DEFAULT_TIME_FORMAT)));
javaTimeModule.addDeserializer(LocalDateTime.class,new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_TIME_FORMAT)));
javaTimeModule.addDeserializer(LocalDate.class,new LocalDateDeserializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT)));
javaTimeModule.addDeserializer(LocalTime.class,new LocalTimeDeserializer(DateTimeFormatter.ofPattern(DEFAULT_TIME_FORMAT)));
//Date序列化和反序列化
javaTimeModule.addSerializer(Date.class, new JsonSerializer<Date>() {
@Override
public void serialize(Date date, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
SimpleDateFormat formatter = new SimpleDateFormat(DEFAULT_DATE_TIME_FORMAT);
String formattedDate = formatter.format(date);
jsonGenerator.writeString(formattedDate);
}
});
javaTimeModule.addDeserializer(Date.class, new JsonDeserializer<Date>() {
@Override
public Date deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
SimpleDateFormat format = new SimpleDateFormat(DEFAULT_DATE_TIME_FORMAT);
String date = jsonParser.getText();
try {
return format.parse(date);
} catch (ParseException e) {
throw new RuntimeException(e);
}
}
});
javaTimeModule.addSerializer(Date.class, new JsonSerializer<Date>() {
@Override
public void serialize(Date date, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
SimpleDateFormat formatter = new SimpleDateFormat(DEFAULT_DATE_FORMAT);
String formattedDate = formatter.format(date);
jsonGenerator.writeString(formattedDate);
}
});
javaTimeModule.addDeserializer(Date.class, new JsonDeserializer<Date>() {
@Override
public Date deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
SimpleDateFormat format = new SimpleDateFormat(DEFAULT_DATE_FORMAT);
String date = jsonParser.getText();
try {
return format.parse(date);
} catch (ParseException e) {
throw new RuntimeException(e);
}
}
});
objectMapper.registerModule(javaTimeModule);
return objectMapper;
}
}
创建DateModel
/**
* @author yly
* @ClassName DateModel
* @Date 2020/2/15 8:06
* @Version 1.0
**/
public class DateModel {
private Date date;
private LocalDateTime localDateTime;
private LocalDate localDate;
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
public LocalDateTime getLocalDateTime() {
return localDateTime;
}
public void setLocalDateTime(LocalDateTime localDateTime) {
this.localDateTime = localDateTime;
}
public LocalDate getLocalDate() {
return localDate;
}
public void setLocalDate(LocalDate localDate) {
this.localDate = localDate;
}
}
创建controller
@RestController
public class DateController {
@RequestMapping("/requestParamDateMOdel")
public DateModel dateModel(DateModel dateModel){
return dateModel;
}
@RequestMapping("/requestBodyDateMOdel")
public DateModel getDateModel(@RequestBody DateModel dateModel){
return dateModel;
}
}
请求
对应的SQL类型
SQL -> Java
date -> LocalDate
time -> LocalTime
timestamp -> LocalDateTime
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