个人如何办网站,网易企业邮箱app下载,岳阳建设公司网站,联盟网站前些天发现了一个巨牛的人工智能学习网站#xff0c;通俗易懂#xff0c;风趣幽默#xff0c;忍不住分享一下给大家。点击跳转到教程。
直接提取重点代码#xff1a; /*** 把结果集合按时间字段排序#xff0c;内部类重写排序规则#xff1a;* param list* return*/priv…前些天发现了一个巨牛的人工智能学习网站通俗易懂风趣幽默忍不住分享一下给大家。点击跳转到教程。
直接提取重点代码 /*** 把结果集合按时间字段排序内部类重写排序规则* param list* return*/private ListWorkWeightDto sortList(ListWorkWeightDto list){Collections.sort(list, new ComparatorWorkWeightDto() {Overridepublic int compare(WorkWeightDto ww1, WorkWeightDto ww2) {return ww2.getStartTime().compareTo(ww1.getStartTime());}});return list;} -------------------------------------------------------------------------------------------------
以下是详情
ListUtils.Java---功能类 [java] view plain copy package com.enable.common.utils; import java.lang.reflect.Field; import java.text.NumberFormat; import java.util.Collections; import java.util.Comparator; import java.util.Date; import java.util.List; /** * author yinaibang * 在数据库中查出来的列表中往往需要对不同的字段重新排序。 一般的做法都是使用排序的字段重新到数据库中查询。 * 如果不到数据库查询直接在第一次查出来的list中排序无疑会提高系统的性能。 下面就写一个通用的方法对list排序 * * 至少需要满足以下5点 * * ①.list元素对象类型任意 * ----使用泛型解决 * * ②.可以按照list元素对象的任意多个属性进行排序,即可以同时指定多个属性进行排序 * ---使用java的可变参数解决 * * ③.list元素对象属性的类型可以是数字(byte、short、int、long、float、double等包括正数、负数、0)、字符串(char、String)、日期(java.util.Date) * ---对于数字统一转换为固定长度的字符串解决,比如数字3和123转换为003和123 ;再比如-15和7转换为-015和007 * ---对于日期可以先把日期转化为long类型的数字数字的解决方法如上 * * ④.list元素对象的属性可以没有相应的getter和setter方法 * ---可以使用java反射进行获取private和protected修饰的属性值 * * ⑤.list元素对象的对象的每个属性都可以指定是升序还是降序 * --使用2个重写的方法(一个方法满足所有属性都按照升序(降序)另外一个方法满足每个属性都能指定是升序(降序)) * * */ public class ListUtils { /** * 对list的元素按照多个属性名称排序, * list元素的属性可以是数字byte、short、int、long、float、double等支持正数、负数、0、char、String、java.util.Date * * * param lsit * param sortname * list元素的属性名称 * param isAsc * true升序false降序 */ public static E void sort(ListE list, final boolean isAsc, final String... sortnameArr) { Collections.sort(list, new ComparatorE() { public int compare(E a, E b) { int ret 0; try { for (int i 0; i sortnameArr.length; i) { ret ListUtils.compareObject(sortnameArr[i], isAsc, a, b); if (0 ! ret) { break; } } } catch (Exception e) { e.printStackTrace(); } return ret; } }); } /** * 给list的每个属性都指定是升序还是降序 * * param list * param sortnameArr 参数数组 * param typeArr 每个属性对应的升降序数组 true升序false降序 */ public static E void sort(ListE list, final String[] sortnameArr, final boolean[] typeArr) { if (sortnameArr.length ! typeArr.length) { throw new RuntimeException(属性数组元素个数和升降序数组元素个数不相等); } Collections.sort(list, new ComparatorE() { public int compare(E a, E b) { int ret 0; try { for (int i 0; i sortnameArr.length; i) { ret ListUtils.compareObject(sortnameArr[i], typeArr[i], a, b); if (0 ! ret) { break; } } } catch (Exception e) { e.printStackTrace(); } return ret; } }); } /** * 对2个对象按照指定属性名称进行排序 * * param sortname * 属性名称 * param isAsc * true升序false降序 * param a * param b * return * throws Exception */ private static E int compareObject(final String sortname, final boolean isAsc, E a, E b) throws Exception { int ret; Object value1 ListUtils.forceGetFieldValue(a, sortname); Object value2 ListUtils.forceGetFieldValue(b, sortname); String str1 value1.toString(); String str2 value2.toString(); if (value1 instanceof Number value2 instanceof Number) { int maxlen Math.max(str1.length(), str2.length()); str1 ListUtils.addZero2Str((Number) value1, maxlen); str2 ListUtils.addZero2Str((Number) value2, maxlen); } else if (value1 instanceof Date value2 instanceof Date) { long time1 ((Date) value1).getTime(); long time2 ((Date) value2).getTime(); int maxlen Long.toString(Math.max(time1, time2)).length(); str1 ListUtils.addZero2Str(time1, maxlen); str2 ListUtils.addZero2Str(time2, maxlen); } if (isAsc) { ret str1.compareTo(str2); } else { ret str2.compareTo(str1); } return ret; } /** * 给数字对象按照指定长度在左侧补0. * * 使用案例: addZero2Str(11,4) 返回 0011, addZero2Str(-18,6)返回 -000018 * * param numObj * 数字对象 * param length * 指定的长度 * return */ public static String addZero2Str(Number numObj, int length) { NumberFormat nf NumberFormat.getInstance(); // 设置是否使用分组 nf.setGroupingUsed(false); // 设置最大整数位数 nf.setMaximumIntegerDigits(length); // 设置最小整数位数 nf.setMinimumIntegerDigits(length); return nf.format(numObj); } /** * 获取指定对象的指定属性值去除private,protected的限制 * * param obj * 属性名称所在的对象 * param fieldName * 属性名称 * return * throws Exception */ public static Object forceGetFieldValue(Object obj, String fieldName) throws Exception { Field field obj.getClass().getDeclaredField(fieldName); Object object null; boolean accessible field.isAccessible(); if (!accessible) { // 如果是private,protected修饰的属性需要修改为可以访问的 field.setAccessible(true); object field.get(obj); // 还原private,protected属性的访问性质 field.setAccessible(accessible); return object; } object field.get(obj); return object; } } UserInfo.java [java] view plain copy package com; import java.text.SimpleDateFormat; import java.util.Date; /** * * author yinaibang * */ public class UserInfo implements java.io.Serializable { private static final long serialVersionUID -3522051445403971732L; private Integer userId; private String username; private Date birthDate; private Integer age; private float fRate; private char ch; public Date getBirthDate() { return birthDate; } public String getBirthDatestr() { SimpleDateFormat formater new SimpleDateFormat(yyyy-MM-dd); return formater.format(getBirthDate()); } public UserInfo(Integer userId, String username, Date birthDate, Integer age, float fRate, char ch) { super(); this.userId userId; this.username username; this.birthDate birthDate; this.age age; this.fRate fRate; this.ch ch; } Override public String toString() { return UserInfo [userId userId , \tusername username , \tbirthDate getBirthDatestr() , \tage age , fRate fRate , ch ch ]; } } Test.java---测试类 [java] view plain copy package com; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.List; import com.enable.common.utils.ListUtils; /** * * author yinaibang * */ public class Test { public static void main(String[] args) throws Exception { Test testObj new Test(); ListUserInfo list new ArrayListUserInfo(); // public UserInfo(Integer userId, String username, Date birthDate,Integer age, float fRate, char ch) SimpleDateFormat formater new SimpleDateFormat(yyyy-MM-dd); UserInfo user1 new UserInfo(3, bbb, formater.parse(1980-12-01), 1, 1.2f, a); UserInfo user2 new UserInfo(0, 126, formater.parse(1900-10-11), 03, -3.6f, c); UserInfo user3 new UserInfo(12, 5, formater.parse(1973-08-21), 15, 9.32f, f); UserInfo user4 new UserInfo(465, 1567, formater.parse(2012-01-26), 20, 12.56f, 0); UserInfo user5 new UserInfo(2006, 4m, formater.parse(2010-05-08), 100, 165.32f, 5); UserInfo user6 new UserInfo(5487, hf67, formater.parse(2016-12-30), 103, 56.32f, m); UserInfo user7 new UserInfo(5487,jigg, formater.parse(2000-10-16), 103, 56.32f, m); UserInfo user8 new UserInfo(5487, jigg, formater.parse(1987-07-25), 103, 56.32f, m); list.add(user1); list.add(user2); list.add(user3); list.add(user4); list.add(user5); list.add(user6); list.add(user7); list.add(user8); System.out.println(\n-------原来序列-------------------); testObj.printfUserInfoList(list); // 按userId升序、username降序、birthDate升序排序 String [] sortNameArr {userId,username,birthDate}; boolean [] isAscArr {true,false,true}; ListUtils.sort(list,sortNameArr,isAscArr); System.out.println(\n--------按按userId升序、username降序、birthDate升序排序如果userId相同则按照username降序,如果username相同则按照birthDate升序------------------); testObj.printfUserInfoList(list); // 按userId、username、birthDate都升序排序 ListUtils.sort(list, true, userId, username,birthDate); System.out.println(\n--------按userId、username、birthDate排序如果userId相同则按照username升序,如果username相同则按照birthDate升序------------------); testObj.printfUserInfoList(list); // 按userId、username都倒序排序 ListUtils.sort(list, false, userId, username); System.out.println(\n--------按userId和username倒序如果userId相同则按照username倒序------------------); testObj.printfUserInfoList(list); // 按username、birthDate都升序排序 ListUtils.sort(list, true, username, birthDate); System.out.println(\n---------按username、birthDate升序如果username相同则按照birthDate升序-----------------); testObj.printfUserInfoList(list); // 按birthDate倒序排序 ListUtils.sort(list, false, birthDate); System.out.println(\n---------按birthDate倒序-----------------); testObj.printfUserInfoList(list); // 按fRate升序排序 ListUtils.sort(list, true, fRate); System.out.println(\n---------按fRate升序-----------------); testObj.printfUserInfoList(list); // 按ch倒序排序 ListUtils.sort(list, false, ch); System.out.println(\n---------按ch倒序-----------------); testObj.printfUserInfoList(list); } private void printfUserInfoList(ListUserInfo list) { for (UserInfo user : list) { System.out.println(user.toString()); } } } 运行结果 [java] view plain copy -------原来序列------------------- UserInfo [userId3, usernamebbb, birthDate1980-12-01, age1, fRate1.2, cha] UserInfo [userId0, username126, birthDate1900-10-11, age3, fRate-3.6, chc] UserInfo [userId12, username5, birthDate1973-08-21, age15, fRate9.32, chf] UserInfo [userId465, username1567, birthDate2012-01-26, age20, fRate12.56, ch0] UserInfo [userId2006, username4m, birthDate2010-05-08, age100, fRate165.32, ch5] UserInfo [userId5487, usernamehf67, birthDate2016-12-30, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate2000-10-16, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate1987-07-25, age103, fRate56.32, chm] --------按按userId升序、username降序、birthDate升序排序如果userId相同则按照username降序,如果username相同则按照birthDate升序------------------ UserInfo [userId0, username126, birthDate1900-10-11, age3, fRate-3.6, chc] UserInfo [userId3, usernamebbb, birthDate1980-12-01, age1, fRate1.2, cha] UserInfo [userId12, username5, birthDate1973-08-21, age15, fRate9.32, chf] UserInfo [userId465, username1567, birthDate2012-01-26, age20, fRate12.56, ch0] UserInfo [userId2006, username4m, birthDate2010-05-08, age100, fRate165.32, ch5] UserInfo [userId5487, usernamejigg, birthDate1987-07-25, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate2000-10-16, age103, fRate56.32, chm] UserInfo [userId5487, usernamehf67, birthDate2016-12-30, age103, fRate56.32, chm] --------按userId、username、birthDate排序如果userId相同则按照username升序,如果username相同则按照birthDate升序------------------ UserInfo [userId0, username126, birthDate1900-10-11, age3, fRate-3.6, chc] UserInfo [userId3, usernamebbb, birthDate1980-12-01, age1, fRate1.2, cha] UserInfo [userId12, username5, birthDate1973-08-21, age15, fRate9.32, chf] UserInfo [userId465, username1567, birthDate2012-01-26, age20, fRate12.56, ch0] UserInfo [userId2006, username4m, birthDate2010-05-08, age100, fRate165.32, ch5] UserInfo [userId5487, usernamehf67, birthDate2016-12-30, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate1987-07-25, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate2000-10-16, age103, fRate56.32, chm] --------按userId和username倒序如果userId相同则按照username倒序------------------ UserInfo [userId5487, usernamejigg, birthDate1987-07-25, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate2000-10-16, age103, fRate56.32, chm] UserInfo [userId5487, usernamehf67, birthDate2016-12-30, age103, fRate56.32, chm] UserInfo [userId2006, username4m, birthDate2010-05-08, age100, fRate165.32, ch5] UserInfo [userId465, username1567, birthDate2012-01-26, age20, fRate12.56, ch0] UserInfo [userId12, username5, birthDate1973-08-21, age15, fRate9.32, chf] UserInfo [userId3, usernamebbb, birthDate1980-12-01, age1, fRate1.2, cha] UserInfo [userId0, username126, birthDate1900-10-11, age3, fRate-3.6, chc] ---------按username、birthDate升序如果username相同则按照birthDate升序----------------- UserInfo [userId2006, username4m, birthDate2010-05-08, age100, fRate165.32, ch5] UserInfo [userId0, username126, birthDate1900-10-11, age3, fRate-3.6, chc] UserInfo [userId465, username1567, birthDate2012-01-26, age20, fRate12.56, ch0] UserInfo [userId12, username5, birthDate1973-08-21, age15, fRate9.32, chf] UserInfo [userId3, usernamebbb, birthDate1980-12-01, age1, fRate1.2, cha] UserInfo [userId5487, usernamehf67, birthDate2016-12-30, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate1987-07-25, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate2000-10-16, age103, fRate56.32, chm] ---------按birthDate倒序----------------- UserInfo [userId5487, usernamehf67, birthDate2016-12-30, age103, fRate56.32, chm] UserInfo [userId465, username1567, birthDate2012-01-26, age20, fRate12.56, ch0] UserInfo [userId2006, username4m, birthDate2010-05-08, age100, fRate165.32, ch5] UserInfo [userId5487, usernamejigg, birthDate2000-10-16, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate1987-07-25, age103, fRate56.32, chm] UserInfo [userId3, usernamebbb, birthDate1980-12-01, age1, fRate1.2, cha] UserInfo [userId12, username5, birthDate1973-08-21, age15, fRate9.32, chf] UserInfo [userId0, username126, birthDate1900-10-11, age3, fRate-3.6, chc] ---------按fRate升序----------------- UserInfo [userId0, username126, birthDate1900-10-11, age3, fRate-3.6, chc] UserInfo [userId3, usernamebbb, birthDate1980-12-01, age1, fRate1.2, cha] UserInfo [userId12, username5, birthDate1973-08-21, age15, fRate9.32, chf] UserInfo [userId465, username1567, birthDate2012-01-26, age20, fRate12.56, ch0] UserInfo [userId5487, usernamehf67, birthDate2016-12-30, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate2000-10-16, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate1987-07-25, age103, fRate56.32, chm] UserInfo [userId2006, username4m, birthDate2010-05-08, age100, fRate165.32, ch5] ---------按ch倒序----------------- UserInfo [userId5487, usernamehf67, birthDate2016-12-30, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate2000-10-16, age103, fRate56.32, chm] UserInfo [userId5487, usernamejigg, birthDate1987-07-25, age103, fRate56.32, chm] UserInfo [userId12, username5, birthDate1973-08-21, age15, fRate9.32, chf] UserInfo [userId0, username126, birthDate1900-10-11, age3, fRate-3.6, chc] UserInfo [userId3, usernamebbb, birthDate1980-12-01, age1, fRate1.2, cha] UserInfo [userId2006, username4m, birthDate2010-05-08, age100, fRate165.32, ch5] UserInfo [userId465, username1567, birthDate2012-01-26, age20, fRate12.56, ch0]
