java简易excel导入导出工具（封装POI）

• Octopus
  • 如何导入excel
  • 如何导出excel
    • github项目地址

Octopus

Octopus 是一个简单的java excel导入导出工具.

如何导入excel

下面是一个excel文件中sheet的数据，有四个学生信息.

studentId	name	sex	inTime	score
20134123	John	M	2013-9-1	89
20124524	Joyce	F	20123-8-31	79
20156243		P	2015-5-15	94
20116522	Nemo	F	2011-2-26

一个学生类，用来保存从excel中读取的学生信息.

//lombok annotations
@Getter
@Setter
@NoArgsConstructor
@ToString
public class Student {

    @ModelLineNumber
    private int lineNum;

    @ModelProperty(value = "id",blankable = false)
    private String studentId;

    @ModelProperty(value = "name",defaultValue = "anonymous")
    private String name;

    @ModelProperty(value = "sex",wrongMsg = "sex must be M or F",pattern = "^M|F$")
    private String sex;

    @ModelProperty(value = "admission",wrongMsg = "admission must be a date")
    private LocalDate inTime;

    @ModelProperty(value = "score",wrongMsg = "score must be numeric",defaultValue = "100")
    private Double score;

}

用代码读取excel，并输出学生信息：

InputStream is = getClass().getResourceAsStream("/test.xlsx");
Workbook workbook = WorkbookFactory.create(is);
Sheet sheet = workbook.getSheetAt(0);

//read students with ReusableSheetReader
SheetReader<ModelEntity<Student>> students = new ReusableSheetReader<>(sheet,1,0,Student.class);

//print students information
for (ModelEntity<Student> student:students) {
    System.out.println(student.toString());
}

输出的学生信息

SimpleModelEntity(entity=Student(lineNum=2, studentId=20134123, name=John, sex=M, inTime=2013-09-01, score=89.0, gradeAndClazz=null), exceptions=[])
SimpleModelEntity(entity=Student(lineNum=3, studentId=20124524, name=Joyce, sex=F, inTime=null, score=79.0, gradeAndClazz=null), exceptions=[cn.chenhuanming.octopus.exception.DataFormatException: in cell (3,4) ,20123-8-31 can not be formatted to class java.time.LocalDate])
SimpleModelEntity(entity=Student(lineNum=4, studentId=20156243, name=anonymous, sex=null, inTime=2015-05-15, score=94.0, gradeAndClazz=null), exceptions=[cn.chenhuanming.octopus.exception.PatternNotMatchException: P and ^M|F$ don't match!])
SimpleModelEntity(entity=Student(lineNum=5, studentId=20116522, name=Nemo, sex=F, inTime=2011-02-26, score=100.0, gradeAndClazz=null), exceptions=[])

通过ModelEntity<Student>，可以获取更多异常信息，例如@ModelProperty的配置信息和所发生的异常.

完整的测试用例：src/test/cn/chenhuanming/octopus/core/SheetReaderTest

如何导出excel

为了说明导出的特性，我们给Student类增加一个属性GradeAndClazz用来表示年级和班级.下面是最终的Student类，可以用来导入导出.

@Getter
@Setter
@NoArgsConstructor
@ToString
public class Student {

    @ModelLineNumber
    private int lineNum;

    @ModelProperty(value = "id",blankable = false)
    private String studentId;

    @ModelProperty(value = "name",defaultValue = "anonymous")
    private String name;

    @ModelProperty(value = "sex",wrongMsg = "sex must be M or F",pattern = "^M|F$")
    private String sex;

    //jackson annotation to format output
    @JsonFormat(pattern = "yyyy-MM-dd")
    @ModelProperty(value = "admission",wrongMsg = "admission must be a date")
    private LocalDate inTime;

    @ModelProperty(value = "score",wrongMsg = "score must be numeric",defaultValue = "100")
    private Double score;

    @ModelIgnore
    private GradeAndClazz gradeAndClazz;

    public Student(String studentId, String name, String sex, LocalDate inTime, Double score,GradeAndClazz gradeAndClazz) {
        this.studentId = studentId;
        this.name = name;
        this.sex = sex;
        this.inTime = inTime;
        this.score = score;
        this.gradeAndClazz = gradeAndClazz;
    }
}

GradeAndClazz类，只有年级和班级两个信息.

@Getter
@Setter
@AllArgsConstructor
public class GradeAndClazz{
    private String grade;
    private String clazz;
}

需要一个xml来配置导出的属性和属性描述作为表头

<?xml version="1.0" encoding="UTF-8"?>
<ExportModel class="entity.Student">
    <Field name="studentId" description="id"></Field>
    <Field name="name" description="name"></Field>
    <Field name="sex" description="sex"></Field>
    <Field name="inTime" description="admission"></Field>
    <Field name="score" description="score"></Field>
    <Field name="gradeAndClazz" description="class info">
        <Field name="grade" description="grade"></Field>
        <Field name="clazz" description="class"></Field>
    </Field>
</ExportModel>

用代码导出学生信息

//prepare workbook and stuednts objects
Workbook workbook = new XSSFWorkbook();
String rootPath = this.getClass().getClassLoader().getResource("").getPath();
FileOutputStream os = new FileOutputStream(rootPath+"/export.xlsx");
GradeAndClazz gradeAndClazz = new GradeAndClazz("2014","R6");
Student student1 = new Student("201223","John","M", LocalDate.now(),98.00,gradeAndClazz);
Student student2 = new Student("204354","Tony","M", LocalDate.now(),87.00,gradeAndClazz);
Student student3 = new Student("202432","Joyce","F", LocalDate.now(),90.00,gradeAndClazz);

//write excel with OneSheetExcelWriter
ExcelWriter<Student> studentExcelWriter = new OneSheetExcelWriter<>(getClass().getClassLoader().getResourceAsStream("studentExport.xml"));

studentExcelWriter.write(workbook,Arrays.asList(student1,student2,student3));
workbook.write(os);

导出结果

                                          |    class info      |
id        name    M     admission   score |---------|----------|
                                          |  grade  |   class  |
---------------------------------------------------------------|
201223    John    M     2017-07-06  98.0  |  2014   |   R6     |
204354    Tony    M     2017-07-06  87.0  |  2014   |   R6     |
202432    Joyce   F     2017-07-06  90.0  |  2014   |   R6     |

可以看到，对于gradeAndClazz属性，会用一个合并单元格来表示.admission因为被@JsonFormat标记，因此会格式化输出日期。事实上Octopus会调用jackson来格式化json后再写入excel.

详细例子在 src/test/cn/chenhuanming/octopus/core/OneSheetExcelWriterTest

github项目地址