类Collections与接口Comparator的简单使用
1 import java.util.ArrayList;
2 import java.util.Collections;
3 import java.util.Comparator;
4 import java.util.List;
5
6 public class TestCompare {
7
8 public static void main(String[] args) {
9
10 List<BookInfo> list = new ArrayList<BookInfo>();
11 list.add(new BookInfo(1, "aa", "hskahs", 10));
12 list.add(new BookInfo(14, "sw", "zxs", 40));
13 list.add(new BookInfo(31, "as", "zx", 10));
14 list.add(new BookInfo(24, "ds", "cds", 20));
15 list.add(new BookInfo(5, "rfr", "cvb", 17));
16 list.add(new BookInfo(20, "saa", "cdg", 100));
17 list.add(new BookInfo(19, "cd", "def", 80));
18
19 System.out.println("----------ID排序----------");
20 Collections.sort(list, new BookInfoIDCompare());
21 for (BookInfo bookInfo : list) {
22 System.out.println(bookInfo);
23 }
24
25 System.out.println("----------名称排序----------");
26
27
28 Collections.sort(list, new BookInfoNameCompare());
29 for (BookInfo bookInfo : list) {
30 System.out.println(bookInfo);
31 }
32
33 System.out.println("----------作者排序----------");
34
35
36 Collections.sort(list, new BookInfoAuthorCompare());
37 for (BookInfo bookInfo : list) {
38 System.out.println(bookInfo);
39 }
40
41
42 System.out.println("-------价格降序排序-------------");
43
44
45 Collections.sort(list, new BookInfoPriceCompare());
46 for (BookInfo bookInfo : list) {
47 System.out.println(bookInfo);
48 }
49 }
50 }
51
52 class BookInfoIDCompare implements Comparator<BookInfo> {
53
54 @Override
55 public int compare(BookInfo o1, BookInfo o2) {
56
57 return o1.getId() > o2.getId() ? 1 : (o1.getId() < o2.getId() ? -1 : 0);
58 }
59
60 }
61
62 class BookInfoNameCompare implements Comparator<BookInfo> {
63
64 @Override
65 public int compare(BookInfo o1, BookInfo o2) {
66
67 return o1.getName().compareTo(o2.getName());
68 }
69 }
70
71 class BookInfoAuthorCompare implements Comparator<BookInfo> {
72
73 @Override
74 public int compare(BookInfo o1, BookInfo o2) {
75
76 return o1.getAuthor().compareTo(o2.getAuthor());
77 }
78 }
79
80 class BookInfoPriceCompare implements Comparator<BookInfo> {
81
82 @Override
83 public int compare(BookInfo o1, BookInfo o2) {
84 return o1.getPrice() > o2.getPrice() ? -1 : (o1.getPrice() < o2.getPrice() ? 1 : 0);
85 }
86 }
87
88 class BookInfo {
89 private int id;
90 private String name;
91 private String author;
92 private int price;
93
94 public BookInfo(int id, String name, String author, int price) {
95 super();
96 this.id = id;
97 this.name = name;
98 this.author = author;
99 this.price = price;
100 }
101
102 public BookInfo() {
103 super();
104 }
105
106 public int getId() {
107 return id;
108 }
109
110 public void setId(int id) {
111 this.id = id;
112 }
113
114 public String getName() {
115 return name;
116 }
117
118 public void setName(String name) {
119 this.name = name;
120 }
121
122 public String getAuthor() {
123 return author;
124 }
125
126 public void setAuthor(String author) {
127 this.author = author;
128 }
129
130 public int getPrice() {
131 return price;
132 }
133
134 public void setPrice(int price) {
135 this.price = price;
136 }
137
138 @Override
139 public String toString() {
140 return "BookInfo [id=" + id + ", name=" + name + ", author=" + author + ", price=" + price + "]";
141 }
142
143 }
