请先阅读 “Java+POI+模板”一：打造复杂Excel 报表
1. 首先创建ExcelUtil类，该类将要实现将一组对象转换为Excel表格，并且可以从Excel表格中读取到一组List对象中。现在我们先创建类并实现单例。
public class ExcelUtil {
private static ExcelUtil eu = new ExcelUtil();
private ExcelUtil(){}
public static ExcelUtil getInstance() {
return eu;
}
}
2. 创建一个Annotation类，用来在对象的get方法上加入的annotation，通过该annotation说明某个属性所对应的标题。
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelResources {
/**
* 属性的标题名称
* @return
*/
String title();
/**
* 在excel的顺序
* @return
*/
int order() default 9999;
}
3. 创建ExcelHeader类，用来存储Excel标题的对象，通过该对象可以获取标题和方法的对应关系
public class ExcelHeader implements Comparable<ExcelHeader>{
/**
* excel的标题名称
*/
private String title;
/**
* 每一个标题的顺序
*/
private int order;
/**
* 说对应方法名称
*/
private String methodName;
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public int getOrder() {
return order;
}
public void setOrder(int order) {
this.order = order;
}
public String getMethodName() {
return methodName;
}
public void setMethodName(String methodName) {
this.methodName = methodName;
}
public int compareTo(ExcelHeader o) {
return order>o.order?1:(order<o.order?-1:0);
}
public ExcelHeader(String title, int order, String methodName) {
super();
this.title = title;
this.order = order;
this.methodName = methodName;
}
@Override
public String toString() {
return "ExcelHeader [title=" + title + ", order=" + order
+ ", methodName=" + methodName + "]";
}
}
4. 创建Model类，并在属性的get方法上面加上我们的Annotation
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 + "]";
}
}
5. 在ExcelUtil中实现exportObj2ExcelByTemplate方法，用于处理将对象转换为Excel。
public void exportObj2ExcelByTemplate(Map<String,String> datas,String template,String outPath, List objs, Class clz, boolean isClasspath){
ExcelTemplate et=ExcelTemplate.getInstance();
if(isClasspath){
et.readTemplateByClasspath(template);
}else{
et.readTemplateByPath(template);
}
List<ExcelHeader> headers=getHeaderList(clz);
Collections.sort(headers);
//输出标题
et.createNewRow();
for (ExcelHeader eh : headers) {
et.createCell(eh.getTitle());
}
//输出值
try {
for(Object obj:objs){
et.createNewRow();
for(ExcelHeader eh:headers){
String mn=eh.getMethodName();
Method m=clz.getDeclaredMethod(mn);
Object rel=m.invoke(obj);
et.createCell(rel.toString());
}
}
} catch (SecurityException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
et.writeToFile(outPath);
}
这里输出值的过程也可以通过导入BeanUtils来处理
//输出值
try {
for(Object obj:objs){
et.createNewRow();
for(ExcelHeader eh:headers){
// String mn=eh.getMethodName();
// Method m=clz.getDeclaredMethod(mn);
// Object rel=m.invoke(obj);
// et.createCell(rel.toString());
et.createCell(BeanUtils.getProperty(obj,getMethodName(eh) ));
}
}
}
exportObj2ExcelByTemplate方法方法会调用getHeaderList方法，来获取Annotation的title以及order
private List<ExcelHeader> getHeaderList(Class clz){
List<ExcelHeader> headers=new ArrayList<ExcelHeader>();
Method[] ms = clz.getDeclaredMethods();
for (Method m : ms) {
String mn =m.getName();
if(mn.startsWith("get")&& m.isAnnotationPresent(ExcelResource.class)){
ExcelResource er=m.getAnnotation(ExcelResource.class);
headers.add(new ExcelHeader(er.title(), er.order(), mn));
}
}
return headers;
}
6. 实现此功能
@Test
public void testObj2Xls() {
List<User> users = new ArrayList<User>();
users.add(new User(1,"aaa","水水水",11));
users.add(new User(2,"sdf","水水水",11));
users.add(new User(3,"sdfde","水水水",11));
users.add(new User(4,"aaa","水水水",11));
users.add(new User(54,"aaa","水水水",11));
users.add(new User(16,"aaa","水水水",11));
ExcelUtil.getInstance().exportObj2ExcelByTemplate(null,"/excel/user.xls","d:/test/poi/tus.xls", users, User.class, true);
}
原先的模板如下图：
插入完成后的模板如下图：
