Hutool Java 工具類庫導出 Excel，超級簡單！

首先在POM.xml中加入GAV

<dependency>
    <groupId>cn.hutool</groupId>
    <artifactId>hutool-all</artifactId>
    <version>5.0.7</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>4.1.1</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml-schemas</artifactId>
    <version>3.17</version>
</dependency>

Excel寫入

實體類

import lombok.AllArgsConstructor;
import lombok.Data;
import java.util.Date;

@Data
@AllArgsConstructor
public class User {
    private String name;
    private int age;
    private Date birthday;
}

然后在控制層使用就行

@RequestMapping("/export")
@ResponseBody
public void export(HttpServletResponse response) {
    List<User> list = new ArrayList<>();
    list.add(new User("zhangsan0", "1231", new Date()));
    list.add(new User("zhangsan1", "1232", new Date()));
    list.add(new User("zhangsan2", "1233", new Date()));
    list.add(new User("zhangsan3", "1234", new Date()));
    list.add(new User("zhangsan4", "1235", new Date()));
    list.add(new User("zhangsan5", "1236", new Date()));
    // 通過工具類創建writer，默認創建xls格式
    ExcelWriter writer = ExcelUtil.getWriter();
    //自定義標題別名
    writer.addHeaderAlias("name", "姓名");
    writer.addHeaderAlias("age", "年齡");
    writer.addHeaderAlias("birthDay", "生日");
    // 合並單元格后的標題行，使用默認標題樣式
    writer.merge(2, "申請人員信息");
    // 一次性寫出內容，使用默認樣式，強制輸出標題
    writer.write(list, true);
    //out為OutputStream，需要寫出到的目標流
    //response為HttpServletResponse對象
    response.setContentType("application/vnd.ms-excel;charset=utf-8");
    //test.xls是彈出下載對話框的文件名，不能為中文，中文請自行編碼
    String name = StringUtils.toUtf8String("申請學院");
    response.setHeader("Content-Disposition", "attachment;filename=" + name + ".xls");
    ServletOutputStream out = null;
    try {
        out = response.getOutputStream();
        writer.flush(out, true);
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        // 關閉writer，釋放內存
        writer.close();
    }
    //此處記得關閉輸出Servlet流
    IoUtil.close(out);
}

 

 Excel讀取

1.讀取Excel中所有行和列，都用列表表示

ExcelReader reader = ExcelUtil.getReader("d:/aaa.xlsx");
List<List<Object>> readAll = reader.read();

2.讀取為Map列表，默認第一行為標題行，Map中的key為標題，value為標題對應的單元格值。

ExcelReader reader = ExcelUtil.getReader("d:/aaa.xlsx");
List<Map<String,Object>> readAll = reader.readAll();

3.讀取為Bean列表，Bean中的字段名為標題，字段值為標題對應的單元格值。

ExcelReader reader = ExcelUtil.getReader("d:/aaa.xlsx");
List<Person> all = reader.readAll(Person.class);

本文Excel導入讀取示例采用的是第三種方法實現，相關代碼如下所示：

@RequestMapping(READ_EXCEL)
public void readExcel(){
    ExcelReader reader = ExcelUtil.getReader("H:\\user.xlsx");
    List<UserDTO> userDTOS = reader.readAll(UserDTO.class);
    //日志輸出讀取到的信息
    log.info(userDTOS.toString());
}

其中UserDTO類的代碼如下所示：

@Data
public class UserDTO {
   
    @NotNull(message = "用戶id不能為空")
    private Integer id;

    @NotNull(message = "用戶名不能為空")
    @Size(min = 4, max = 16, message = "用戶名長度錯誤")
    private String userName;

    @NotNull(message = "密碼不能為空")
    @Size(min = 4, max = 16, message = "密碼長度錯誤")
    private String loginPassword;

    @NotNull(message = "郵箱不能為空")
    @Email(message = "郵箱格式錯誤")
    private String email;

    @NotNull(message = "日期不能為空")
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    @JSONField(format = "yyyy-MM-dd HH:mm:ss")
    private Date createDate;
}

 1、ExcelUtil

從文件中讀取Excel為ExcelReader

ExcelReader reader = ExcelUtil.getReader(FileUtil.file("test.xlsx"));

從流中讀取Excel為ExcelReader

ExcelReader reader = ExcelUtil.getReader(ResourceUtil.getStream("aaa.xlsx"));

讀取指定的sheet

ExcelReader reader;
//通過sheet編號獲取
reader = ExcelUtil.getReader(FileUtil.file("test.xlsx"), 0);
//通過sheet名獲取
reader = ExcelUtil.getReader(FileUtil.file("test.xlsx"), "sheet1");

2、ExcelReader

讀取Excel中所有行和列，都用列表表示

ExcelReader reader = ExcelUtil.getReader("d:/aaa.xlsx");
List<List<Object>> readAll = reader.read();

讀取為Map列表，默認第一行為標題行，Map中的key為標題，value為標題對應的單元格值

ExcelReader reader = ExcelUtil.getReader("d:/aaa.xlsx");
List<Map<String,Object>> readAll = reader.readAll();

讀取為Bean列表，Bean中的字段名為標題，字段值為標題對應的單元格值

ExcelReader reader = ExcelUtil.getReader("d:/aaa.xlsx");
List<Person> all = reader.readAll(Person.class);

3、ExcelWriter

Hutool將Excel寫出封裝為ExcelWriter，原理為包裝了Workbook對象，每次調用merge（合並單元格）或者write（寫出數據）方法后只是將數據寫入到Workbook，並不寫出文件，只有調用flush或者close方法后才會真正寫出文件。
由於機制原因，在寫出結束后需要關閉ExcelWriter對象，調用close方法即可關閉，此時才會釋放Workbook對象資源，否則帶有數據的Workbook一直會常駐內存

（1） 將行列對象寫出到Excel

List<String> row1 = CollUtil.newArrayList("aa", "bb", "cc", "dd");
List<String> row2 = CollUtil.newArrayList("aa1", "bb1", "cc1", "dd1");
List<String> row3 = CollUtil.newArrayList("aa2", "bb2", "cc2", "dd2");
List<String> row4 = CollUtil.newArrayList("aa3", "bb3", "cc3", "dd3");
List<String> row5 = CollUtil.newArrayList("aa4", "bb4", "cc4", "dd4");

List<List<String>> rows = CollUtil.newArrayList(row1, row2, row3, row4, row5);

//通過工具類創建writer
ExcelWriter writer = ExcelUtil.getWriter("d:/writeTest.xlsx");
//通過構造方法創建writer
//ExcelWriter writer = new ExcelWriter("d:/writeTest.xls");

//跳過當前行，既第一行，非必須，在此演示用
writer.passCurrentRow();

//合並單元格后的標題行，使用默認標題樣式
writer.merge(row1.size() - 1, "測試標題");
//一次性寫出內容，強制輸出標題
writer.write(rows, true);
//關閉writer，釋放內存
writer.close();

（2）寫出Map數據

Map<String, Object> row1 = new LinkedHashMap<>();
row1.put("姓名", "張三");
row1.put("年齡", 23);
row1.put("成績", 88.32);
row1.put("是否合格", true);
row1.put("考試日期", DateUtil.date());

Map<String, Object> row2 = new LinkedHashMap<>();
row2.put("姓名", "李四");
row2.put("年齡", 33);
row2.put("成績", 59.50);
row2.put("是否合格", false);
row2.put("考試日期", DateUtil.date());

ArrayList<Map<String, Object>> rows = CollUtil.newArrayList(row1, row2);

// 通過工具類創建writer
ExcelWriter writer = ExcelUtil.getWriter("d:/writeMapTest.xlsx");
// 合並單元格后的標題行，使用默認標題樣式
writer.merge(row1.size() - 1, "一班成績單");
// 一次性寫出內容，使用默認樣式，強制輸出標題
writer.write(rows, true);
// 關閉writer，釋放內存
writer.close();

（3）寫出Bean數據

public class TestBean {
    private String name;
    private int age;
    private double score;
    private boolean isPass;
    private Date examDate;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public double getScore() {
        return score;
    }

    public void setScore(double score) {
        this.score = score;
    }

    public boolean isPass() {
        return isPass;
    }

    public void setPass(boolean isPass) {
        this.isPass = isPass;
    }

    public Date getExamDate() {
        return examDate;
    }

    public void setExamDate(Date examDate) {
        this.examDate = examDate;
    }
}

TestBean bean1 = new TestBean();
bean1.setName("張三");
bean1.setAge(22);
bean1.setPass(true);
bean1.setScore(66.30);
bean1.setExamDate(DateUtil.date());

TestBean bean2 = new TestBean();
bean2.setName("李四");
bean2.setAge(28);
bean2.setPass(false);
bean2.setScore(38.50);
bean2.setExamDate(DateUtil.date());

List<TestBean> rows = CollUtil.newArrayList(bean1, bean2);

// 通過工具類創建writer
ExcelWriter writer = ExcelUtil.getWriter("d:/writeBeanTest.xlsx");
// 合並單元格后的標題行，使用默認標題樣式
writer.merge(4, "一班成績單");
// 一次性寫出內容，使用默認樣式，強制輸出標題
writer.write(rows, true);
// 關閉writer，釋放內存
writer.close();

（4）自定義Bean的key別名（排序標題）

在寫出Bean的時候，我們可以調用ExcelWriter對象的addHeaderAlias方法自定義Bean中key的別名，這樣就可以寫出自定義標題了

// 通過工具類創建writer
ExcelWriter writer = ExcelUtil.getWriter("d:/writeBeanTest.xlsx");

//自定義標題別名
writer.addHeaderAlias("name", "姓名");
writer.addHeaderAlias("age", "年齡");
writer.addHeaderAlias("score", "分數");
writer.addHeaderAlias("isPass", "是否通過");
writer.addHeaderAlias("examDate", "考試時間");

// 合並單元格后的標題行，使用默認標題樣式
writer.merge(4, "一班成績單");
// 一次性寫出內容，使用默認樣式，強制輸出標題
writer.write(rows, true);
// 關閉writer，釋放內存
writer.close();