准备
user.sql
CREATE TABLE `user` (
`id` int(20) NOT NULL AUTO_INCREMENT COMMENT '主键',
`username` varchar(100) DEFAULT NULL COMMENT '用户名',
`password` varchar(100) DEFAULT NULL COMMENT '密码',
`nickname` varchar(100) DEFAULT NULL COMMENT '昵称',
`age` int(10) DEFAULT NULL COMMENT '年龄',
`gender` varchar(10) DEFAULT NULL COMMENT '性别',
`birthday` date DEFAULT NULL COMMENT '生日',
`phone` varchar(20) DEFAULT NULL COMMENT '电话',
`email` varchar(50) DEFAULT NULL COMMENT '邮箱',
`address` varchar(200) DEFAULT NULL COMMENT '地址',
`create_datetime` datetime DEFAULT NULL COMMENT '创建时间',
`update_datetime` datetime DEFAULT NULL COMMENT '更新时间',
`delete_status` int(1) DEFAULT NULL COMMENT '删除状态',
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COMMENT='用户';
User.java
package com.xzh.demo.domin;
import com.fasterxml.jackson.annotation.JsonFormat;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.Getter;
import lombok.NoArgsConstructor;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;
import org.springframework.format.annotation.DateTimeFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
// 主键
private Integer id;
// 用户名
private String username;
// 密码
private String password;
// 昵称
private String nickname;
// 年龄
private Integer age;
// 性别
private String gender;
// 生日
@JsonFormat(timezone="GMT+8", pattern="yyyy-MM-dd")
@DateTimeFormat(pattern="yyyy-MM-dd")
private Date birthday;
// 电话
private String phone;
// 邮箱
private String email;
// 地址
private String address;
// 创建时间
@JsonFormat(timezone="GMT+8", pattern="yyyy-MM-dd HH:mm:ss")
@DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss")
private Date createDatetime;
// 更新时间
@JsonFormat(timezone="GMT+8", pattern="yyyy-MM-dd HH:mm:ss")
@DateTimeFormat(pattern="yyyy-MM-dd HH:mm:ss")
private Date updateDatetime;
// 删除状态
private Integer deleteStatus;
public User(String username, String password, String nickname, Integer age, String gender, Date birthday, String phone, String email, String address, Date createDatetime, Date updateDatetime, Integer deleteStatus) {
this.username = username;
this.password = password;
this.nickname = nickname;
this.age = age;
this.gender = gender;
this.birthday = birthday;
this.phone = phone;
this.email = email;
this.address = address;
this.createDatetime = createDatetime;
this.updateDatetime = updateDatetime;
this.deleteStatus = deleteStatus;
}
@Override
public String toString() {
SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String birthdayStr = birthday != null ? sdf1.format(birthday) : "'null'";
String createDatetimeStr = createDatetime != null ? sdf2.format(createDatetime) : "'null'";
String updateDatetimeStr = updateDatetime != null ? sdf2.format(updateDatetime) : "'null'";
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
", nickname='" + nickname + '\'' +
", age=" + age +
", gender='" + gender + '\'' +
", birthday=" + birthdayStr +
", phone='" + phone + '\'' +
", email='" + email + '\'' +
", address='" + address + '\'' +
", createDatetime=" + createDatetimeStr +
", updateDatetime=" + updateDatetimeStr +
", deleteStatus=" + deleteStatus +
'}';
}
}
数据准备
public class StudyList {
SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
private List<User> userList = new ArrayList<User>() {{
try {
add(new User(1, "zs", "3", "张三", 14, "男",
sdf1.parse("2020-07-06"), "13067201234", "133266@qq.com", "福州",
sdf2.parse("2020-07-06 00:51:44"), sdf2.parse("2020-07-06 00:49:04"), 0));
add(new User(2, "ls", "123", "李四", 12, "男",
sdf1.parse("2020-08-29"), "13067201234", "133266@qq.com", "四川",
sdf2.parse("2020-07-07 09:16:18"), sdf2.parse("2020-07-06 00:49:04"), 0));
add(new User(3, "ww", "1", "王五", 15, "男",
sdf1.parse("2020-07-06"), "13067201234", "133266@qq.com", "福州",
sdf2.parse("2020-07-06 00:51:44"), sdf2.parse("2020-07-06 00:49:04"), 0));
add(new User(4, "super", "3", "超管", 13, "男",
sdf1.parse("2020-07-06"), "13067201234", "133266@qq.com", "福州",
sdf2.parse("2020-07-06 00:51:44"), sdf2.parse("2020-07-06 00:49:04"), 0));
add(new User(5, "zs", "3", "管理员1", 14, "男",
sdf1.parse("2020-07-06"), "13067201234", "133266@qq.com", "福州",
sdf2.parse("2020-07-06 00:51:44"), sdf2.parse("2020-07-06 00:49:04"), 0));
add(new User(6, "root;", "2", "管理员2", 16, "男",
sdf1.parse("2020-07-06"), "13067201234", "133266@qq.com", "福州",
sdf2.parse("2020-07-06 00:51:44"), sdf2.parse("2020-07-06 00:49:04"), 0));
add(new User(7, "root", ";2", "管理员3", 14, "男",
sdf1.parse("2020-07-06"), "13067201234", "133266@qq.com", "福州",
sdf2.parse("2020-07-06 00:51:44"), sdf2.parse("2020-07-06 00:49:04"), 0));
} catch (ParseException e) {
e.printStackTrace();
}
}};
}
List 常用用法
添加
// 添加
public void add() {
User user = new User();
user.setId(10);
user.setUsername("test");
userList.add(user);
}
插入
// 插入
public void insert() {
User user = new User();
user.setId(10);
user.setUsername("test");
userList.add(2, user);
}
删除
// 删除（按对对象）
public void delete1() {
// boolean remove(Object o);
userList.remove(userList.get(0));
}
// 删除（按位序）
public void delete2() {
// E remove(int index)
User remove = userList.remove(2);
}
// 删除（按条件）
public void delete3() {
// boolean removeIf(Predicate<? super E> filter)
userList.removeIf(obj -> obj.getPassword().equals("1"));
}
替换
// 替换
public void reset() {
User user = userList.get(1);
user.setUsername("替换");
userList.set(1, user);
}
获取
// 获取
public void get() {
User user = userList.get(1);
System.out.println(user);
}
截取
// 截取
public void sub() {
// List<E> subList(int fromIndex, int toIndex); 范围 [fromIndex, toIndex)
List<User> list = userList.subList(3, 4);
}
转数组
// 转数组
public void toArray() {
List<String> list = Arrays.asList("a", "b", "c");
String[] array = list.toArray(new String[list.size()]);
for (String s : array) {
System.out.print(s + " ");
}
}
判空
判断元素个数是否为0，不能判断是否为空指针
public void isEmpty() {
List list = new ArrayList();
System.out.println(list.isEmpty());
}
判断是否为空指针且元素个数是否为0
public void isBlank() {
boolean bool = userList == null || userList.isEmpty();
System.out.println(bool);
}
判包含
单字段
// 判包含（单字段）
public void isContains() {
long count = userList.stream().map(User::getUsername).filter(e -> "ls".equals(e)).count();
System.out.println(count > 0);
}
多字段
// 判包含（多字段）
public void isContains2() {
long count = userList.stream().map(e -> e.getUsername() + ',' + e.getPassword()).filter(e -> "zs,,1".equals(e)).count();
System.out.println(count > 0);
}
// 判包含（多字段）
public void isContains3() {
User user = new User();
user.setUsername("zs,");
user.setPassword("1");
boolean b = userIndexOf(user) >= 0;
System.out.println(b);
}
public int userIndexOf(Object o) {
if (o == null) {
for (int i = 0; i < userList.size(); i++)
if (userList.get(i)==null)
return i;
} else {
for (int i = 0; i < userList.size(); i++)
if (userEquals(o, userList.get(i)))
return i;
}
return -1;
}
public boolean userEquals(Object u, Object o) {
if (u == o) return true;
if (o == null || u.getClass() != o.getClass()) return false;
User user2 = (User) o;
User user1 = (User) u;
return new EqualsBuilder()
.append(user1.getUsername(), user2.getUsername())
.append(user1.getPassword(), user2.getPassword())
.isEquals();
}
判重
单字段
// 判重（单字段）
public void isRepeat() {
List<String> collect = userList.stream().map(User::getUsername).collect(Collectors.toList());
Set<?> noRepeatSet = new HashSet<>(collect);
boolean bool = !(collect.size() == noRepeatSet.size());
System.out.println(bool);
}
多字段
// 判重（多字段）
public void isRepeat2() {
List<String> collect = userList.stream().map(e -> e.getUsername() + ',' + e.getPassword()).collect(Collectors.toList());
Set<?> noRepeatSet = new HashSet<>(collect);
boolean bool = !(collect.size() == noRepeatSet.size());
System.out.println(bool);
}
去重
单字段
// 去重1（单字段）
public void distinct1() {
List<User> list = new ArrayList<>(userList.stream()
.collect(Collectors.toMap(User::getUsername, Function.identity(), (oldValue, newValue) -> newValue))
.values());
listToStr(list);
}
// 去重2（单字段）
public void distinct2() {
List<User> list = new ArrayList<>(userList.stream()
.collect(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(User::getUsername)))));
listToStr(list);
}
多字段
// 去重1（多字段）
public void distinct1_2() {
List<User> list = new ArrayList<>(userList.stream()
.collect(Collectors.toMap(e -> e.getUsername() + ',' + e.getPassword(), Function.identity(), (oldValue, newValue) -> newValue))
.values());
listToStr(list);
}
// 去重2（多字段）
public void distinct2_2() {
List<User> list = userList.stream()
.collect(Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(e -> e.getUsername() + ',' + e.getPassword()))), ArrayList::new));
listToStr(list);
}
去重
//查重
public static <T> List<T> findRepeat(Collection<T> datas) {
if (datas instanceof Set) {
return new ArrayList<>();
}
HashSet<T> set = new HashSet<T>();
List<T> repeatEles = new ArrayList<T>();
for (T t : datas) {
if (set.contains(t)) {
repeatEles.add(t);
} else {
set.add(t);
}
}
return repeatEles;
}
排序
单字段
// 排序 单字段
public void sort(){
List<User> collect = userList.stream().sorted(
Comparator.comparing(User::getAge)).collect(Collectors.toList());
listToStr(collect);
}
多字段
// 排序 多字段
public void sort2(){
List<User> collect = userList.stream().sorted(
Comparator.comparing(User::getAge).reversed().thenComparing(User::getPassword)).collect(Collectors.toList());
listToStr(collect);
}
封装工具类
ListUtils.java
package com.xzh.demo.util;
import jdk.internal.org.objectweb.asm.tree.analysis.Value;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.poi.ss.formula.functions.T;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.*;
import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.stream.Collectors;
public class ListUtils {
public static final String DESC = "desc";
public static final String ASC = "asc";
public static <T> int indexOf(List<T> list, Object obj, BiFunction<? super T, ? super Object, Boolean> equ) {
if (obj == null) {
for (int i = 0; i < list.size(); i++)
if (list.get(i) == null)
return i;
} else {
for (int i = 0; i < list.size(); i++)
if (equ.apply(list.get(i), obj))
return i;
}
return -1;
}
public static <T> int indexOf(List<T> list, Object obj, String... fieldNames) {
if (obj == null) {
for (int i = 0; i < list.size(); i++)
if (list.get(i) == null)
return i;
} else {
for (int i = 0; i < list.size(); i++)
if (equal(list.get(i), obj, fieldNames))
return i;
}
return -1;
}
/**
* List 转 String, 用于遍历输出
*/
public static String toStr(List<?> list) {
return toStr(list, true);
}
/**
* List 转 String, 用于遍历输出
*/
public static String toStr(List<?> list, boolean print) {
StringBuffer str = new StringBuffer();
for (Object o : list) {
str.append("\n" + o.toString());
}
if (print) {
System.out.println(str.toString());
}
return str.toString();
}
/**
* 判空，只判断元素个数是否为0，不能判断是否为空指针
*/
public static boolean isEmpty(List<?> list) {
return list.isEmpty();
}
/**
* 判空
*/
public static boolean isNullEmpty(List<?> list) {
return list == null || list.isEmpty();
}
/**
* 判非空
*/
public static boolean isNotNullEmpty(List<?> list) {
return !isNullEmpty(list);
}
/**
* 判包含
*
* @param list 集合List
* @param mapper 转换方法
* @param filter 判包含字符串
* @return
*/
public static <T> boolean isContains(List<T> list, Function<? super T, ? super Object> mapper, Object filter) {
if (filter == null) {
return false;
}
long count = list.stream().map(mapper).filter(e -> filter.equals(e)).count();
return count > 0;
}
/**
* 判包含
*
* @param list 集合List
* @param equ equals方法
* @param filter 判包含字符串
* @return
*/
public static <T> boolean isContains(List<T> list, BiFunction<? super T, ? super Object, Boolean> equ, Object filter) {
if (filter == null) {
return false;
}
return indexOf(list, filter, equ) >= 0;
}
/**
* 判包含
*
* @param list 集合List
* @param filter 判包含字符串
* @param fieldNames 判断equals相等的字段名
* @return
*/
public static <T> boolean isContains(List<T> list, Object filter, String... fieldNames) {
if (filter == null) {
return false;
}
return indexOf(list, filter, fieldNames) >= 0;
}
/**
* 判重
*
* @param list 集合List
* @param mapper 转换方法
* @return
*/
public static <T> boolean isRepeat(List<T> list, Function<? super T, ? super Object> mapper) {
List<Object> collect = list.stream().map(mapper).collect(Collectors.toList());
Set<?> noRepeatSet = new HashSet<>(collect);
return !(collect.size() == noRepeatSet.size());
}
/**
* 判重
*
* @param list 集合List
* @param equ equals方法
* @return
*/
public static <T> boolean isRepeat(List<T> list, BiFunction<? super T, ? super Object, Boolean> equ) {
List<T> noRepeat = new ArrayList<>();
for (T t : list) {
if (isContains(noRepeat, equ, t))
return true;
else
noRepeat.add(t);
}
return !(noRepeat.size() == list.size());
}
/**
* 判重
*
* @param list 集合List
* @param fieldNames 判断equals相等的字段名
* @return
*/
public static <T> boolean isRepeat(List<T> list, String... fieldNames) {
List<T> noRepeat = new ArrayList<>();
for (T t : list) {
if (isContains(noRepeat, t, fieldNames))
return true;
else
noRepeat.add(t);
}
return !(noRepeat.size() == list.size());
}
/**
* 去重
*
* @param list 集合List
* @param mapper 转换方法
* @param isCover 是否覆盖
* @return
*/
public static <T> List<T> removeRepeat(List<T> list, Function<? super T, ? super Object> mapper, boolean isCover) {
List<T> noRepeat = new ArrayList<T>(list.stream()
.collect(Collectors.toMap(mapper, Function.identity(), (oldValue, newValue) -> isCover ? newValue : oldValue))
.values());
return noRepeat;
}
/**
* 去重
*
* @param list 集合List
* @param equ equals方法
* @param isCover 是否覆盖
* @return
*/
public static <T> List<T> removeRepeat(List<T> list, BiFunction<? super T, ? super Object, Boolean> equ, boolean isCover) {
List<T> noRepeat = new ArrayList<>();
for (T t : list) {
int i = indexOf(noRepeat, t, equ);
if (i >= 0) {
if (isCover)
noRepeat.set(i, t);
} else {
noRepeat.add(t);
}
}
return noRepeat;
}
/**
* 去重
*
* @param list 集合List
* @param isCover 是否覆盖
* @param fieldNames 判断equals相等的字段名
* @return
*/
public static <T> List<T> removeRepeat(List<T> list, boolean isCover, String... fieldNames) {
List<T> noRepeat = new ArrayList<>();
for (T t : list) {
int i = indexOf(noRepeat, t, fieldNames);
if (i >= 0) {
if (isCover)
noRepeat.set(i, t);
} else {
noRepeat.add(t);
}
}
return noRepeat;
}
/**
* 去重
*
* @param list 集合List
* @param split 分隔符
* @param fieldNames 判断equals相等的字段名
* @return
*/
public static <T> List<T> removeRepeat(List<T> list, String split, String... fieldNames) {
List<T> noRepeat = new ArrayList<>(list.stream()
.collect(Collectors.toCollection(() -> new TreeSet<T>(Comparator.comparing(e -> getValuesOfGet(e, split, fieldNames) + "")))));
return noRepeat;
}
/**
* 查重
*
* @param list 集合List
* @param fieldNames 判断equals相等的字段名
* @return
*/
public static <T> List<T> findRepeat(List<T> list, String... fieldNames) {
List<T> noRrepeat = new ArrayList<>();
List<T> repeat = new ArrayList<>();
for (T t : list) {
if (isContains(noRrepeat, t, fieldNames))
repeat.add(t);
else
noRrepeat.add(t);
}
return repeat;
}
/**
* 对list中的元素按升序排列
*
* @param list 集合List
* @param field 用于排序的字段
* @return
*/
public static <T> List<T> sorted(List<T> list, final String field) {
return sorted(list, field, null);
}
/**
* 对list中的元素进行排序
*
* @param list 集合List
* @param field 用于排序的字段
* @param sort 排序方式: ListUtils.DESC(降序) ListUtils.ASC(升序).
* @return
*/
public static <T, U> List<T> sorted(List<T> list, final String field, final String sort) {
if (isNullEmpty(list)) {
return list;
}
Comparator<T> comparing;
boolean isDesc = sort != null && sort.toLowerCase().equals(DESC) ? false : true;
Object value = getValueOfGet(list.get(0), field);
if (value instanceof Integer) {
comparing = isDesc ? Comparator.comparing(e -> (Integer) getValueOfGet(e, field)) :
Comparator.comparing(e -> (Integer) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Double) {
comparing = isDesc ? Comparator.comparing(e -> (Double) getValueOfGet(e, field)) :
Comparator.comparing(e -> (Double) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Long) {
comparing = isDesc ? Comparator.comparing(e -> (Long) getValueOfGet(e, field)) :
Comparator.comparing(e -> (Long) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Float) {
comparing = isDesc ? Comparator.comparing(e -> (Float) getValueOfGet(e, field)) :
Comparator.comparing(e -> (Float) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Date) {
comparing = isDesc ? Comparator.comparing(e -> (Date) getValueOfGet(e, field)) :
Comparator.comparing(e -> (Date) getValueOfGet(e, field), Comparator.reverseOrder());
} else {
comparing = isDesc ? Comparator.comparing(e -> (String) getValueOfGet(e, field)) :
Comparator.comparing(e -> (String) getValueOfGet(e, field), Comparator.reverseOrder());
}
return list.stream().sorted(comparing).collect(Collectors.toList());
}
/**
* 对list中的元素按fields和sorts进行排序,
* fields[i]指定排序字段,sorts[i]指定排序方式.如果sorts[i]为空则默认按升序排列.
*
* @param list
* @param fields
* @param sorts
* @return
*/
public static <T> List<T> sorted(List<T> list, String[] fields, String[] sorts) {
if (isNullEmpty(list)) {
return list;
}
if (fields != null && fields.length > 0) {
Comparator<T> comparing = null;
for (int i = 0; i < fields.length; i++) {
final String field = fields[i];
String tmpSort = ASC;
if (sorts != null && sorts.length > i && sorts[i] != null) {
tmpSort = sorts[i];
}
final String sort = tmpSort;
boolean isDesc = sort != null && sort.toLowerCase().equals(DESC) ? false : true;
Object value = getValueOfGet(list.get(0), field);
if (i == 0) {
if (value instanceof Integer) {
comparing = isDesc ? Comparator.comparing(e -> (Integer) getValueOfGet(e, field)) :
Comparator.comparing(e -> (Integer) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Double) {
comparing = isDesc ? Comparator.comparing(e -> (Double) getValueOfGet(e, field)) :
Comparator.comparing(e -> (Double) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Long) {
comparing = isDesc ? Comparator.comparing(e -> (Long) getValueOfGet(e, field)) :
Comparator.comparing(e -> (Long) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Float) {
comparing = isDesc ? Comparator.comparing(e -> (Float) getValueOfGet(e, field)) :
Comparator.comparing(e -> (Float) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Date) {
comparing = isDesc ? Comparator.comparing(e -> (Date) getValueOfGet(e, field)) :
Comparator.comparing(e -> (Date) getValueOfGet(e, field), Comparator.reverseOrder());
} else {
comparing = isDesc ? Comparator.comparing(e -> (String) getValueOfGet(e, field)) :
Comparator.comparing(e -> (String) getValueOfGet(e, field), Comparator.reverseOrder());
}
} else {
if (value instanceof Integer) {
comparing = isDesc ? comparing.thenComparing(e -> (Integer) getValueOfGet(e, field)) :
comparing.thenComparing(e -> (Integer) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Double) {
comparing = isDesc ? comparing.thenComparing(e -> (Double) getValueOfGet(e, field)) :
comparing.thenComparing(e -> (Double) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Long) {
comparing = isDesc ? comparing.thenComparing(e -> (Long) getValueOfGet(e, field)) :
comparing.thenComparing(e -> (Long) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Float) {
comparing = isDesc ? comparing.thenComparing(e -> (Float) getValueOfGet(e, field)) :
comparing.thenComparing(e -> (Float) getValueOfGet(e, field), Comparator.reverseOrder());
} else if (value instanceof Date) {
comparing = isDesc ? comparing.thenComparing(e -> (Date) getValueOfGet(e, field)) :
comparing.thenComparing(e -> (Date) getValueOfGet(e, field), Comparator.reverseOrder());
} else {
comparing = isDesc ? comparing.thenComparing(e -> (String) getValueOfGet(e, field)) :
comparing.thenComparing(e -> (String) getValueOfGet(e, field), Comparator.reverseOrder());
}
}
}
return list.stream().sorted(comparing).collect(Collectors.toList());
}
return list;
}
/**
* 对list中的元素按升序排列.
*
* @param list 排序集合
* @param field 排序字段
* @return
*/
public static <T> List<T> sort(List<T> list, final String field) {
return sort(list, field, null);
}
/**
* 对list中的元素进行排序.
*
* @param list 排序集合
* @param field 排序字段
* @param sort 排序方式: ListUtils.DESC(降序) ListUtils.ASC(升序).
* @return
*/
@SuppressWarnings("unchecked")
public static <T> List<T> sort(List<T> list, final String field, final String sort) {
if (isEmpty(list)) {
return list;
}
Collections.sort(list, new Comparator() {
@Override
public int compare(Object a, Object b) {
int ret = 0;
try {
Field f = a.getClass().getDeclaredField(field);
f.setAccessible(true);
Class<?> type = f.getType();
if (type == int.class) {
ret = ((Integer) f.getInt(a)).compareTo((Integer) f.getInt(b));
} else if (type == double.class) {
ret = ((Double) f.getDouble(a)).compareTo((Double) f.getDouble(b));
} else if (type == long.class) {
ret = ((Long) f.getLong(a)).compareTo((Long) f.getLong(b));
} else if (type == float.class) {
ret = ((Float) f.getFloat(a)).compareTo((Float) f.getFloat(b));
} else if (type == Date.class) {
ret = ((Date) f.get(a)).compareTo((Date) f.get(b));
} else if (isImplementsOf(type, Comparable.class)) {
ret = ((Comparable) f.get(a)).compareTo((Comparable) f.get(b));
} else {
ret = String.valueOf(f.get(a)).compareTo(String.valueOf(f.get(b)));
}
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
if (sort != null && sort.toLowerCase().equals(DESC)) {
return -ret;
} else {
return ret;
}
}
});
return list;
}
/**
* 对list中的元素按fields和sorts进行排序,
* fields[i]指定排序字段,sorts[i]指定排序方式.如果sorts[i]为空则默认按升序排列.
*
* @param list
* @param fields
* @param sorts
* @return
*/
@SuppressWarnings("unchecked")
public static <T> List<T> sort(List<T> list, String[] fields, String[] sorts) {
if (fields != null && fields.length > 0) {
for (int i = fields.length - 1; i >= 0; i--) {
final String field = fields[i];
String tmpSort = ASC;
if (sorts != null && sorts.length > i && sorts[i] != null) {
tmpSort = sorts[i];
}
final String sort = tmpSort;
Collections.sort(list, new Comparator() {
@Override
public int compare(Object a, Object b) {
int ret = 0;
try {
Field f = a.getClass().getDeclaredField(field);
f.setAccessible(true);
Class<?> type = f.getType();
if (type == int.class) {
ret = ((Integer) f.getInt(a)).compareTo((Integer) f.getInt(b));
} else if (type == double.class) {
ret = ((Double) f.getDouble(a)).compareTo((Double) f.getDouble(b));
} else if (type == long.class) {
ret = ((Long) f.getLong(a)).compareTo((Long) f.getLong(b));
} else if (type == float.class) {
ret = ((Float) f.getFloat(a)).compareTo((Float) f.getFloat(b));
} else if (type == Date.class) {
ret = ((Date) f.get(a)).compareTo((Date) f.get(b));
} else if (isImplementsOf(type, Comparable.class)) {
ret = ((Comparable) f.get(a)).compareTo((Comparable) f.get(b));
} else {
ret = String.valueOf(f.get(a)).compareTo(String.valueOf(f.get(b)));
}
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
if (sort != null && sort.toLowerCase().equals(DESC)) {
return -ret;
} else {
return ret;
}
}
});
}
}
return list;
}
/**
* 判断对象实现的所有接口中是否包含szInterface
*
* @param clazz
* @param szInterface
* @return
*/
private static boolean isImplementsOf(Class<?> clazz, Class<?> szInterface) {
boolean flag = false;
Class<?>[] face = clazz.getInterfaces();
for (Class<?> c : face) {
if (c == szInterface) {
flag = true;
} else {
flag = isImplementsOf(c, szInterface);
}
}
if (!flag && null != clazz.getSuperclass()) {
return isImplementsOf(clazz.getSuperclass(), szInterface);
}
return flag;
}
private static <T> boolean equal(T a, Object b, String... fieldNams) {
if (a == b) return true;
if (b == null || a.getClass() != b.getClass()) return false;
T t2 = (T) b;
T t1 = (T) a;
EqualsBuilder equalsBuilder = new EqualsBuilder();
for (String fieldNam : fieldNams) {
equalsBuilder.append(getValueOfGet(t1, fieldNam), getValueOfGet(t2, fieldNam));
}
return equalsBuilder.isEquals();
}
/******************************************
*********** 工具，反射相关 ***************
******************************************/
/**
* 通过字段名从对象或对象的父类中得到字段的值
*
* @param object 对象实例
* @param fieldName 字段名
* @return 字段对应的值
* @throws Exception
*/
private static Object getValue(Object object, String fieldName) throws Exception {
if (object == null) {
return null;
}
if (StringUtils.isBlank(fieldName)) {
return null;
}
Field field = null;
Class<?> clazz = object.getClass();
for (; clazz != Object.class; clazz = clazz.getSuperclass()) {
try {
field = clazz.getDeclaredField(fieldName);
field.setAccessible(true);
return field.get(object);
} catch (Exception e) {
}
}
return null;
}
/**
* 通过字段名从对象或对象的父类中得到字段的值（调用字典的get方法）
*
* @param object 对象实例
* @param fieldName 字段名
* @return 字段对应的值
*/
private static Object getValueOfGet(Object object, String fieldName) {
if (object == null) {
return null;
}
if (StringUtils.isBlank(fieldName)) {
return null;
}
Field field = null;
Class<?> clazz = object.getClass();
for (; clazz != Object.class; clazz = clazz.getSuperclass()) {
try {
field = clazz.getDeclaredField(fieldName);
field.setAccessible(true);
PropertyDescriptor pd = new PropertyDescriptor(field.getName(), clazz);
//获得get方法
Method getMethod = pd.getReadMethod();
//执行get方法返回一个Object
return getMethod.invoke(object);
} catch (Exception e) {
}
}
return null;
}
/**
* 通过字段名数组从对象或对象的父类中得到字段的值（调用字典的get方法）
*
* @param object 对象实例
* @param fieldNames 字段名
* @return 字段对应的值
*/
private static Object getValuesOfGet(Object object, String spit, String... fieldNames) {
if (object == null) {
return null;
}
for (String fieldName : fieldNames) {
if (StringUtils.isBlank(fieldName)) {
return null;
}
}
Field field = null;
Class<?> clazz = object.getClass();
for (; clazz != Object.class; clazz = clazz.getSuperclass()) {
try {
String values = "";
for (String fieldName : fieldNames) {
field = clazz.getDeclaredField(fieldName);
field.setAccessible(true);
PropertyDescriptor pd = new PropertyDescriptor(field.getName(), clazz);
//获得get方法
Method getMethod = pd.getReadMethod();
//执行get方法返回一个Object
values += spit + getMethod.invoke(object);
}
return values.substring(spit.length());
} catch (Exception e) {
}
}
return null;
}
}
工具类的使用
indexOf
单字段
public void indexOf1(List list){
User user = new User();
user.setUsername("ww");
int i = ListUtils.indexOf(list, user, (a,b)->{
User t1 = (User) a;
User t2 = (User) b;
return t1.getUsername().equals(t2.getUsername());
});
System.out.println(i);
}
// output: 2
public void indexOf2(List list){
int i = ListUtils.indexOf(list, "ww", (a,b)->{
User t = (User) a;
return t.getUsername().equals(b);
});
System.out.println(i);
}
// output: 2
public void indexOf3(List list){
User user = new User();
user.setUsername("ls");
int i = ListUtils.indexOf(list, user, "username");
System.out.println(i);
}
// output: 1
多字段
public void indexOf1(List list) {
User user = new User();
user.setUsername("ww");
user.setNickname("王五");
int i = ListUtils.indexOf(list, user, (a, b) -> {
User t1 = (User) a;
User t2 = (User) b;
boolean equals = new EqualsBuilder()
.append(t1.getUsername(), t2.getUsername())
.append(t1.getNickname(), t2.getNickname())
.isEquals();
return equals;
});
System.out.println(i);
}
// output: 2
public void indexOf2(List list) {
int i = ListUtils.indexOf(list, "ww;王五", (a, b) -> {
User t = (User) a;
return b.equals(t.getUsername() + ";" + t.getNickname());
});
System.out.println(i);
}
// output: 2
public void indexOf3(List list) {
User user = new User();
user.setUsername("ls");
user.setNickname("李四");
int i = ListUtils.indexOf(list, user, "username", "nickname");
System.out.println(i);
}
// output: 1
判空
public void isEmpty() {
List<String> list1 = null;
List<String> list2 = new ArrayList<>();
boolean b1 = ListUtils.isEmpty(list1); //java.lang.NullPointerException
boolean b2 = ListUtils.isEmpty(list2); //true
System.out.println(b1);
System.out.println(b2);
}
public void isNullEmpty() {
List<String> list1 = null;
List<String> list2 = new ArrayList<>();
boolean b1 = ListUtils.isNullEmpty(list1); //true
boolean b2 = ListUtils.isNullEmpty(list2); //true
System.out.println(b1);
System.out.println(b2);
}
判包含
单字段
public void isContains1(List list) {
User user = new User();
user.setUsername("ww");
boolean bool = ListUtils.isContains(list, (a,b)->{
User t1 = (User) a;
User t2 = (User) b;
return t1.getUsername().equals(t2.getUsername());
},user);
System.out.println(bool);
}
public void isContains2(List list) {
boolean bool = ListUtils.isContains(list, User::getUsername,"ww");
System.out.println(bool);
}
public void isContains3(List list) {
boolean bool = ListUtils.isContains(list, (a,b)->{
User t = (User) a;
String t2 = (String) b;
return t.getUsername().equals(t2);
}, "ww");
System.out.println(bool);
}
public void isContains4(List list) {
User user = new User();
user.setUsername("ww");
boolean bool = ListUtils.isContains(list, user, "username");
System.out.println(bool);
}
多字段
public void isContains1(List list) {
User user = new User();
user.setUsername("ww");
user.setNickname("王五");
boolean bool = ListUtils.isContains(list, (a, b) -> {
User t1 = (User) a;
User t2 = (User) b;
boolean equals = new EqualsBuilder()
.append(t1.getUsername(), t2.getUsername())
.append(t1.getNickname(), t2.getNickname())
.isEquals();
return equals;
}, user);
System.out.println(bool);
}
public void isContains2(List<User> list) {
boolean bool = ListUtils.isContains(list, e -> e.getUsername() + ";" + e.getNickname(), "ww;王五");
System.out.println(bool);
}
public void isContains3(List list) {
boolean bool = ListUtils.isContains(list, (a, b) -> {
User t = (User) a;
String t2 = (String) b;
return t2.equals(t.getUsername() + ";" + t.getNickname());
}, "ww;王五");
System.out.println(bool);
}
public void isContains4(List list) {
User user = new User();
user.setUsername("ww");
user.setNickname("王五");
boolean bool = ListUtils.isContains(list, user, "username", "nickname");
System.out.println(bool);
}
判重
单字段
public void isRepeat1(List list) {
boolean bool = ListUtils.isRepeat(list, (a, b) -> {
User t1 = (User) a;
User t2 = (User) b;
return t1.getUsername().equals(t2.getUsername());
});
System.out.println(bool);
}
public void isRepeat2(List<User> list) {
boolean bool = ListUtils.isRepeat(list, User::getUsername);
System.out.println(bool);
}
public void isRepeat3(List list) {
boolean bool = ListUtils.isRepeat(list, "username");
System.out.println(bool);
}
多字段
public void isRepeat1(List list) {
boolean bool = ListUtils.isRepeat(list, (a, b) -> {
User t1 = (User) a;
User t2 = (User) b;
boolean equals = new EqualsBuilder()
.append(t1.getUsername(), t2.getUsername())
.append(t1.getPassword(), t2.getPassword())
.isEquals();
return equals;
});
System.out.println(bool);
}
public void isRepeat2(List<User> list) {
boolean bool = ListUtils.isRepeat(list, e -> e.getUsername() + ";" + e.getPassword());
System.out.println(bool);
}
public void isRepeat3(List list) {
boolean bool = ListUtils.isRepeat(list, "username", "password");
System.out.println(bool);
}
去重
单字段
public void removeRepeat1(List<User> list) {
List<User> userList1 = ListUtils.removeRepeat(list, (a, b) -> {
User t1 = (User) a;
User t2 = (User) b;
return t1.getUsername().equals(t2.getUsername());
}, true);
List<User> userList2 = ListUtils.removeRepeat(list, (a, b) -> {
User t1 = (User) a;
User t2 = (User) b;
return t1.getUsername().equals(t2.getUsername());
}, false);
ListUtils.toStr(userList1, true);
ListUtils.toStr(userList2, true);
}
public void removeRepeat2(List<User> list) {
List<User> userList1 = ListUtils.removeRepeat(list, User::getUsername, true);
List<User> userList2 = ListUtils.removeRepeat(list, User::getUsername, false);
ListUtils.toStr(userList1, true);
ListUtils.toStr(userList2, true);
}
public void removeRepeat3(List list) {
List<User> userList1 = ListUtils.removeRepeat(list, true,"username");
List<User> userList2 = ListUtils.removeRepeat(list, false,"username");
ListUtils.toStr(userList1, true);
ListUtils.toStr(userList2, true);
}
public void removeRepeat4(List list) {
List<User> userList1 = ListUtils.removeRepeat(list, ";","username");
ListUtils.toStr(userList1, true);
}
多字段
public void removeRepeat1(List<User> list) {
List<User> userList1 = ListUtils.removeRepeat(list, (a, b) -> {
User t1 = (User) a;
User t2 = (User) b;
boolean equals = new EqualsBuilder()
.append(t1.getUsername(), t2.getUsername())
.append(t1.getPassword(), t2.getPassword())
.isEquals();
return equals;
}, true);
List<User> userList2 = ListUtils.removeRepeat(list, (a, b) -> {
User t1 = (User) a;
User t2 = (User) b;
boolean equals = new EqualsBuilder()
.append(t1.getUsername(), t2.getUsername())
.append(t1.getPassword(), t2.getPassword())
.isEquals();
return equals;
}, false);
ListUtils.toStr(userList1, true);
ListUtils.toStr(userList2, true);
}
public void removeRepeat2(List<User> list) {
List<User> userList1 = ListUtils.removeRepeat(list, e -> e.getUsername() + ";" + e.getPassword(), true);
List<User> userList2 = ListUtils.removeRepeat(list, e -> e.getUsername() + ";" + e.getPassword(), false);
ListUtils.toStr(userList1, true);
ListUtils.toStr(userList2, true);
}
public void removeRepeat3(List list) {
List<User> userList1 = ListUtils.removeRepeat(list, true, "username", "password");
List<User> userList2 = ListUtils.removeRepeat(list, false, "username", "password");
ListUtils.toStr(userList1, true);
ListUtils.toStr(userList2, true);
}
public void removeRepeat4(List list) {
List<User> userList1 = ListUtils.removeRepeat(list, ";", "username", "password");
ListUtils.toStr(userList1, true);
}
查重
单字段
public void findRepeat(List list) {
List<User> userList = ListUtils.findRepeat(list, "username");
ListUtils.toStr(userList, true);
}
多字段
public void findRepeat(List list) {
List<User> userList = ListUtils.findRepeat(list, "username", "password");
ListUtils.toStr(userList, true);
}
排序
单字段
public void sort1(List list) {
List<User> userList = ListUtils.sort(list, "id", "desc");
ListUtils.toStr(userList, true);
}
public void sort2(List list) {
List<User> userList = ListUtils.sort(list, "age");
ListUtils.toStr(userList, true);
}
多字段
public void sort(List list) {
List<User> userList = ListUtils.sort(list, new String[]{"age","id"}, new String[]{"asc","desc"});
ListUtils.toStr(userList, true);
}
