# easyexcel核心功能

## *读任意大小的03、07版Excel不会OO]<br />
## *读Excel自动通过注解，把结果映射为java模型<br />
## *读Excel支持多sheet<br />
## *读Excel时候是否对Excel内容做trim()增加容错<br />
## *写小量数据的03版Excel（不要超过2000行）<br />
## *写任意大07版Excel不会OOM<br />
## *写Excel通过注解将表头自动写入Excel<br />
## *写Excel可以自定义Excel样式 如：字体，加粗，表头颜色，数据内容颜色<br />
## *写Excel到多个不同sheet<br />
## *写Excel时一个sheet可以写多个Table<br />
## *写Excel时候自定义是否需要写表头<br />

## 读Excel

使用easyexcel解析03、07版本的Excel只是ExcelTypeEnum不同，其他使用完全相同，使用者无需知道底层解析的差异。

### 无java模型直接把excel解析的每行结果以List&lt;String&gt;返回 在ExcelListener获取解析结果

读excel代码示例如下：
```
    @Test
    public void testExcel2003NoModel() {
        InputStream inputStream = getInputStream("loan1.xls");
        try {
            // 解析每行结果在listener中处理
            ExcelListener listener = new ExcelListener();

            ExcelReader excelReader = new ExcelReader(inputStream, ExcelTypeEnum.XLS, null, listener);
            excelReader.read();
        } catch (Exception e) {

        } finally {
            try {
                inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
```
ExcelListener示例代码如下：
```
 /* 解析监听器，
 * 每解析一行会回调invoke()方法。
 * 整个excel解析结束会执行doAfterAllAnalysed()方法
 *
 * 下面只是我写的一个样例而已，可以根据自己的逻辑修改该类。
 * @author jipengfei
 * @date 2017/03/14
 */
public class ExcelListener extends AnalysisEventListener {

    //自定义用于暂时存储data。
    //可以通过实例获取该值
    private List<Object> datas = new ArrayList<Object>();
    public void invoke(Object object, AnalysisContext context) {
        System.out.println("当前行："+context.getCurrentRowNum());
        System.out.println(object);
        datas.add(object);//数据存储到list，供批量处理，或后续自己业务逻辑处理。
        doSomething(object);//根据自己业务做处理
    }
    private void doSomething(Object object) {
        //1、入库调用接口
    }
    public void doAfterAllAnalysed(AnalysisContext context) {
       // datas.clear();//解析结束销毁不用的资源
    }
    public List<Object> getDatas() {
        return datas;
    }
    public void setDatas(List<Object> datas) {
        this.datas = datas;
    }
}
```
### 有java模型映射 
java模型写法如下：
```
public class LoanInfo extends BaseRowModel {
    @ExcelProperty(index = 0)
    private String bankLoanId;
    
    @ExcelProperty(index = 1)
    private Long customerId;
    
    @ExcelProperty(index = 2,format = "yyyy/MM/dd")
    private Date loanDate;
    
    @ExcelProperty(index = 3)
    private BigDecimal quota;
    
    @ExcelProperty(index = 4)
    private String bankInterestRate;
    
    @ExcelProperty(index = 5)
    private Integer loanTerm;
    
    @ExcelProperty(index = 6,format = "yyyy/MM/dd")
    private Date loanEndDate;
    
    @ExcelProperty(index = 7)
    private BigDecimal interestPerMonth;

    @ExcelProperty(value = {"一级表头","二级表头"})
    private BigDecimal sax;
}
```
@ExcelProperty(index = 3)数字代表该字段与excel对应列号做映射，也可以采用 @ExcelProperty(value = {"一级表头","二级表头"})用于解决不确切知道excel第几列和该字段映射，位置不固定，但表头的内容知道的情况。
```
    @Test
    public void testExcel2003WithReflectModel() {
        InputStream inputStream = getInputStream("loan1.xls");
        try {
            // 解析每行结果在listener中处理
            AnalysisEventListener listener = new ExcelListener();

            ExcelReader excelReader = new ExcelReader(inputStream, ExcelTypeEnum.XLS, null, listener);

            excelReader.read(new Sheet(1, 2, LoanInfo.class));
        } catch (Exception e) {

        } finally {
            try {
                inputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
```
带模型解析与不带模型解析主要在构造new Sheet(1, 2, LoanInfo.class)时候包含class。Class需要继承BaseRowModel暂时BaseRowModel没有任何内容，后面升级可能会增加一些默认的数据。

## 写Excel

### 每行数据是List&lt;String&gt;无表头

```
  OutputStream out = new FileOutputStream("/Users/jipengfei/77.xlsx");
        try {
            ExcelWriter writer = new ExcelWriter(out, ExcelTypeEnum.XLSX,false);
            //写第一个sheet, sheet1  数据全是List<String> 无模型映射关系
            Sheet sheet1 = new Sheet(1, 0);
            sheet1.setSheetName("第一个sheet");
            writer.write(getListString(), sheet1);
            writer.finish();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
```

### 每行数据是一个java模型有表头----表头层级为一

生成Excel格式如下图
![屏幕快照 2017-06-02 上午9.49.39.png](http://ata2-img.cn-hangzhou.img-pub.aliyun-inc.com/dfcb44d05380e2e26bce93f850d9fc99.png)

模型写法如下：
```
public class ExcelPropertyIndexModel extends BaseRowModel {

    @ExcelProperty(value = "姓名" ,index = 0)
    private String name;

    @ExcelProperty(value = "年龄",index = 1)
    private String age;

    @ExcelProperty(value = "邮箱",index = 2)
    private String email;

    @ExcelProperty(value = "地址",index = 3)
    private String address;

    @ExcelProperty(value = "性别",index = 4)
    private String sax;

    @ExcelProperty(value = "高度",index = 5)
    private String heigh;

    @ExcelProperty(value = "备注",index = 6)
    private String last;
}
```
   @ExcelProperty(value = "姓名",index = 0) value是表头数据，默认会写在excel的表头位置，index代表第几列。
```
 @Test
    public void test1() throws FileNotFoundException {
        OutputStream out = new FileOutputStream("/Users/jipengfei/78.xlsx");
        try {
            ExcelWriter writer = new ExcelWriter(out, ExcelTypeEnum.XLSX);
            //写第一个sheet, sheet1  数据全是List<String> 无模型映射关系
            Sheet sheet1 = new Sheet(1, 0,ExcelPropertyIndexModel.class);
            writer.write(getData(), sheet1);
            writer.finish();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
```

### 每行数据是一个java模型有表头----表头层级为多层级

生成Excel格式如下图：
![屏幕快照 2017-06-02 上午9.53.07.png](http://ata2-img.cn-hangzhou.img-pub.aliyun-inc.com/0cdb1673665e7940cd670871afb4b3d7.png)
java模型写法如下：
```
public class MultiLineHeadExcelModel extends BaseRowModel {

    @ExcelProperty(value = {"表头1","表头1","表头31"},index = 0)
    private String p1;

    @ExcelProperty(value = {"表头1","表头1","表头32"},index = 1)
    private String p2;

    @ExcelProperty(value = {"表头3","表头3","表头3"},index = 2)
    private int p3;

    @ExcelProperty(value = {"表头4","表头4","表头4"},index = 3)
    private long p4;

    @ExcelProperty(value = {"表头5","表头51","表头52"},index = 4)
    private String p5;

    @ExcelProperty(value = {"表头6","表头61","表头611"},index = 5)
    private String p6;

    @ExcelProperty(value = {"表头6","表头61","表头612"},index = 6)
    private String p7;

    @ExcelProperty(value = {"表头6","表头62","表头621"},index = 7)
    private String p8;

    @ExcelProperty(value = {"表头6","表头62","表头622"},index = 8)
    private String p9;
}
```
写Excel写法同上，只需将ExcelPropertyIndexModel.class改为MultiLineHeadExcelModel.class


### 一个Excel多个sheet写法

```
 @Test
    public void test1() throws FileNotFoundException {

        OutputStream out = new FileOutputStream("/Users/jipengfei/77.xlsx");
        try {
            ExcelWriter writer = new ExcelWriter(out, ExcelTypeEnum.XLSX,false);
            //写第一个sheet, sheet1  数据全是List<String> 无模型映射关系
            Sheet sheet1 = new Sheet(1, 0);
            sheet1.setSheetName("第一个sheet");
            writer.write(getListString(), sheet1);

            //写第二个sheet sheet2  模型上打有表头的注解，合并单元格
            Sheet sheet2 = new Sheet(2, 3, MultiLineHeadExcelModel.class, "第二个sheet", null);
            sheet2.setTableStyle(getTableStyle1());
            writer.write(getModeldatas(), sheet2);

            //写sheet3  模型上没有注解，表头数据动态传入
            List<List<String>> head = new ArrayList<List<String>>();
            List<String> headCoulumn1 = new ArrayList<String>();
            List<String> headCoulumn2 = new ArrayList<String>();
            List<String> headCoulumn3 = new ArrayList<String>();
            headCoulumn1.add("第一列");
            headCoulumn2.add("第二列");
            headCoulumn3.add("第三列");
            head.add(headCoulumn1);
            head.add(headCoulumn2);
            head.add(headCoulumn3);
            Sheet sheet3 = new Sheet(3, 1, NoAnnModel.class, "第三个sheet", head);
            writer.write(getNoAnnModels(), sheet3);
            writer.finish();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
```

### 一个sheet中有多个表格

```
@Test
    public void test2() throws FileNotFoundException {
        OutputStream out = new FileOutputStream("/Users/jipengfei/77.xlsx");
        try {
            ExcelWriter writer = new ExcelWriter(out, ExcelTypeEnum.XLSX,false);

            //写sheet1  数据全是List<String> 无模型映射关系
            Sheet sheet1 = new Sheet(1, 0);
            sheet1.setSheetName("第一个sheet");
            Table table1 = new Table(1);
            writer.write(getListString(), sheet1, table1);
            writer.write(getListString(), sheet1, table1);

            //写sheet2  模型上打有表头的注解
            Table table2 = new Table(2);
            table2.setTableStyle(getTableStyle1());
            table2.setClazz(MultiLineHeadExcelModel.class);
            writer.write(getModeldatas(), sheet1, table2);

            //写sheet3  模型上没有注解，表头数据动态传入,此情况下模型field顺序与excel现实顺序一致
            List<List<String>> head = new ArrayList<List<String>>();
            List<String> headCoulumn1 = new ArrayList<String>();
            List<String> headCoulumn2 = new ArrayList<String>();
            List<String> headCoulumn3 = new ArrayList<String>();
            headCoulumn1.add("第一列");
            headCoulumn2.add("第二列");
            headCoulumn3.add("第三列");
            head.add(headCoulumn1);
            head.add(headCoulumn2);
            head.add(headCoulumn3);
            Table table3 = new Table(3);
            table3.setHead(head);
            table3.setClazz(NoAnnModel.class);
            table3.setTableStyle(getTableStyle2());
            writer.write(getNoAnnModels(), sheet1, table3);
            writer.write(getNoAnnModels(), sheet1, table3);

            writer.finish();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
```
## 测试数据分析

![POI usermodel PK easyexcel(Excel 2003).png](http://ata2-img.cn-hangzhou.img-pub.aliyun-inc.com/02c4bfbbab99a649788523d04f84a42f.png)
![POI usermodel PK easyexcel(Excel 2007).png](http://ata2-img.cn-hangzhou.img-pub.aliyun-inc.com/f6a8a19ec959f0eb564e652de523fc9e.png)
![POI usermodel PK easyexcel(Excel 2003) (1).png](http://ata2-img.cn-hangzhou.img-pub.aliyun-inc.com/26888f7ea1cb8dc56db494926544edf7.png)
![POI usermodel PK easyexcel(Excel 2007) (1).png](http://ata2-img.cn-hangzhou.img-pub.aliyun-inc.com/4de1ac95bdfaa4b1870b224af4f4cb75.png)
从上面的性能测试可以看出easyexcel在解析耗时上比poiuserModel模式弱了一些。主要原因是我内部采用了反射做模型字段映射，中间我也加了cache，但感觉这点差距可以接受的。但在内存消耗上差别就比较明显了，easyexcel在后面文件再增大，内存消耗几乎不会增加了。但poi userModel就不一样了，简直就要爆掉了。想想一个excel解析200M，同时有20个人再用估计一台机器就挂了。