请先阅读 “Java+POI+模板”一:打造复杂Excel 报表
“Java+POI+模板”二:基于对象列表输出到excel(利用反射)
我们会处理如下图所示的两个Excel,将之转化为我们的对象。
第一张图对应的对象类如下:
public class User { private int id; private String username; private String nickname; private int age; @ExcelResources(title="用户标识",order=1) public int getId() { return id; } public void setId(int id) { this.id = id; } @ExcelResources(title="用户名",order=2) public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } @ExcelResources(title="用户昵称",order=3) public String getNickname() { return nickname; } public void setNickname(String nickname) { this.nickname = nickname; } @ExcelResources(title="用户年龄",order=4) public int getAge() { return age; } public void setAge(int age) { this.age = age; } public User(int id, String username, String nickname, int age) { super(); this.id = id; this.username = username; this.nickname = nickname; this.age = age; } public User() { super(); } @Override public String toString() { return "User [id=" + id + ", username=" + username + ", nickname=" + nickname + ", age=" + age + "]"; } }
第二张图对应的对象类如下:
public class Student { private int id; private String name; private String no; private String sex; @ExcelResources(title="学生标识",order=1) public int getId() { return id; } public void setId(int id) { this.id = id; } @ExcelResources(title="学生姓名") public String getName() { return name; } public void setName(String name) { this.name = name; } @ExcelResources(title="学生学号", order=2) public String getNo() { return no; } public void setNo(String no) { this.no = no; } @ExcelResources(title="学生性别") public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public Student(int id, String name, String no, String sex) { super(); this.id = id; this.name = name; this.no = no; this.sex = sex; } public Student() { super(); } @Override public String toString() { return "Student [id=" + id + ", name=" + name + ", no=" + no + ", sex=" + sex + "]"; } }
处理上述的Excel我们需要知道其文件路径,读取Excel的开始行和结束行,所以我们的代码如下。具体的操作我们交给handleExcel2Objs方法来处理。
/** * 从文件路径读取相应的Excel文件到对象列表 * @param path 文件路径下的path * @param clz 对象类型 * @param readLine 开始行,注意是标题所在行 * @param tailLine 底部有多少行,在读入对象时,会减去这些行 * @return */ public List<Object> readExcel2ObjsByPath(String path,Class clz,int readLine,int tailLine) { Workbook wb = null; try { wb = WorkbookFactory.create(new File(path)); return handleExcel2Objs(wb, clz, readLine,tailLine); } catch (InvalidFormatException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return null; }
handleExcel2Objs方法首先会调用getHeaderMap方法,将Model类ExcelResources注解的Title与单元格的Title做匹配。然后将单元格的列号作为key,Model的get方法名改为set方法名,作为字符串设为value。返回一个Map。
/** * 将Model类ExcelResources注解的Title与单元格的Title做匹配 * 将单元格的列号作为key,Model的get方法名改为set方法名,作为字符串设为value */ private Map<Integer,String> getHeaderMap(Row titleRow, Class clz){ List<ExcelHeader> headers=getHeaderList(clz); Map<Integer,String> maps=new HashMap<Integer,String>(); for (Cell c : titleRow) { String title=c.getStringCellValue(); for (ExcelHeader eh : headers) { if(eh.getTitle().equals(title)){ maps.put(c.getColumnIndex(), eh.getMethodName().replace("get", "set")); break; } } } return maps; }
getHeaderMap方法又会调用getHeaderList方法来返回返回Model类里面所有带有ExcelResources注解的get方法的注解信息。
/** * 将Model类ExcelResources注解的Title与单元格的Title做匹配 * 将单元格的列号作为key,Model的get方法名改为set方法名,作为字符串设为value */ private Map<Integer,String> getHeaderMap(Row titleRow, Class clz){ List<ExcelHeader> headers=getHeaderList(clz); Map<Integer,String> maps=new HashMap<Integer,String>(); for (Cell c : titleRow) { String title=c.getStringCellValue(); for (ExcelHeader eh : headers) { if(eh.getTitle().equals(title)){ maps.put(c.getColumnIndex(), eh.getMethodName().replace("get", "set")); break; } } } return maps; }
有了上述方法,handleExcel2Objs方法便可轻松将Excel转换为参数中的clz对象
/** * 将Excel转换为参数中的clz对象 * @param wb 我们所要处理的Workbook * @param clz 对象类型 * @param readLine 开始行,注意是标题所在行 * @param tailLine 底部有多少行,在读入对象时,会减去这些行 * @return */ private List<Object> handleExcel2Objs(Workbook wb,Class clz,int readLine,int tailLine) { Sheet sheet=wb.getSheetAt(0); List<Object> objs=null; try { Row row=sheet.getRow(readLine); objs = new ArrayList<Object>(); Map<Integer,String> maps =getHeaderMap(row, clz); if(maps==null||maps.size()<=0) throw new RuntimeException("要读取的Excel的格式不正确,检查是否设定了合适的行"); Object obj=null; for(int i=readLine+1;i<=sheet.getLastRowNum()-tailLine;i++){ row=sheet.getRow(i); obj=clz.newInstance(); for (Cell c : row) { int ci = c.getColumnIndex(); String mn=maps.get(ci).substring(3); mn=mn.substring(0, 1).toLowerCase()+mn.substring(1); BeanUtils.copyProperty(obj, mn,this.getCellValue(c)); } objs.add(obj); } } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } return objs; }
这样我们的代码就写好了,下面是测试代码。
针对于第一张图,我们第0行和最后两行是不需要的,所以传入的readLine是1,tailLine是2
针对第二张图,我们就是从0行开始读,底部也没有多余的行,所以readLine和tailLine都是0
@Test public void testRead01(){ List<Object> us=ExcelUtil.getInstance().readExcel2ObjsByPath("d:/test/poi/tus.xls", User.class,1,2); for(Object obj:us){ User user=(User)obj; System.out.println(user); } } @Test public void testRead02(){ List<Object> stus=ExcelUtil.getInstance().readExcel2ObjsByPath("d:/test/poi/ss1.xls", Student.class,0,0); for(Object obj:stus){ Student stu=(Student)obj; System.out.println(stu); } }
输出的值如下:
testRead01: User [id=1, username=aaa, nickname=水水水, age=11] User [id=2, username=sdf, nickname=水水水, age=11] User [id=3, username=sdfde, nickname=水水水, age=11] User [id=4, username=aaa, nickname=水水水, age=11] User [id=54, username=aaa, nickname=水水水, age=11] User [id=16, username=aaa, nickname=水水水, age=11] testRead02 Student [id=1, name=张三, no=1123123, sex=男] Student [id=2, name=张三, no=1123123, sex=男] Student [id=3, name=张三, no=1123123, sex=男] Student [id=4, name=张三, no=1123123, sex=男]