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CSV和集合对象基于Annotation操作封装

随着项目上线,暂时处于闲置状态,所以趁闲带着团队对在这一年项目中做的比较好的组件,工具和实践总结和抽取出来,在我后续的随笔中将会陆续发布出来。今天主要是一个简单的maven小组件,对opencsv基于Annotation简单的封装,使得我们可以轻易的将CSV文件转化为List对像和把List对像导出为CSV文件。

项目托管地址于github https://github.com/greengerong/opencsv-utils

对于代码就不用多说了,简单看看如何使用。

Object

 

 1 package opencsv.utils;
 2 
 3  
 4 
 5 public class Person {
 6 
 7  
 8 
 9     private int id;
10 
11  
12 
13     @Csv("person name")
14 
15     private String name;
16 
17  
18 
19     @Ignore
20 
21     private int age;
22 
23  
24 
25     public Person(int id, String name, int age) {
26 
27         this.id = id;
28 
29         this.name = name;
30 
31         this.age = age;
32 
33     }
34 
35  
36 
37     public Person() {
38 
39  
40 
41     }
42 
43  
44 
45     public int getId() {
46 
47         return id;
48 
49     }
50 
51  
52 
53     public void setId(int id) {
54 
55         this.id = id;
56 
57     }
58 
59  
60 
61     public String getName() {
62 
63         return name;
64 
65     }
66 
67  
68 
69     public void setName(String name) {
70 
71         this.name = name;
72 
73     }
74 
75  
76 
77     public int getAge() {
78 
79         return age;
80 
81     }
82 
83  
84 
85     public void setAge(int age) {
86 
87         this.age = age;
88 
89     }
90 
91 }
92 
93
复制代码

 

Mapping会自动将没有ignore的字段作为CSV的映射属性名作为CSV列头,如果针对特殊列则可以标记@CSV解决。

1: 读取CSV:

(1) 基于Annotation映射方式

 1 @Test
 2 
 3     public void shouldGetPersonFromCSV() throws Exception {
 4 
 5         StringReader reader = new StringReader("id,person name\n1,name1\n2,name2\n");
 6 
 7         List<Person> personList = personCsvMapper
 8 
 9                 .withMapping("id", "id")
10 
11                 .withMapping("person name", "name")
12 
13                 .fromCsv(reader);
14 
15  
16 
17         assertThat(personList.size(), is(2));
18 
19  
20 
21         final Person first = personList.get(0);
22 
23         assertThat(first.getId(), is(1));
24 
25         assertThat(first.getName(), is("name1"));
26 
27  
28 
29         final Person second = personList.get(1);
30 
31         assertThat(second.getId(), is(2));
32 
33         assertThat(second.getName(), is("name2"));
34 
35  
36 
37     }
38 
39

(2) 自定义映射方式

 1 @Test
 2 
 3     public void shouldToCsv() throws Exception {
 4 
 5         personCsvMapper.withMapping(new CsvColumnMapping(Person.class));
 6 
 7         final ArrayList<Person> list = new ArrayList<Person>();
 8 
 9         list.add(new Person(1, "name1", 20));
10 
11         list.add(new Person(2, "name2", 30));
12 
13         final StringWriter writer = new StringWriter();
14 
15  
16 
17         personCsvMapper.toCsv(writer, list);
18 
19  
20 
21         final String text = writer.toString();
22 
23         assertThat(text, is("id,person name\n1,name1\n2,name2\n"));
24 
25     }

2: CSV输出

 

 @Test

    public void shouldGetPersonFromCsv() throws Exception {

        StringReader reader = new StringReader("id,person name\n1,name1\n2,name2\n");

        List<Person> personList = new CsvMapper<Person>(Person.class)

                .withMapping(new CsvColumnMapping(Person.class))

                .fromCsv(reader);

        assertThat(personList.size(), is(2));

        final Person first = personList.get(0);

        assertThat(first.getId(), is(1));

        assertThat(first.getName(), is("name1"));

        final Person second = personList.get(1);

        assertThat(second.getId(), is(2));

        assertThat(second.getName(), is("name2"));

    }

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