一、定义注解，用于vo类中标记使用到的属性
import java.lang.annotation.elementtype;import java.lang.annotation.retention;import java.lang.annotation.retentionpolicy;import java.lang.annotation.target;/** * @author fc * @date 2018-09-18 */@target(value = {elementtype.field})@retention(retentionpolicy.runtime)public @interface allow { string title() default "undefined";}
二、反射工具类
import org.apache.poi.hssf.usermodel.hssfworkbook;import org.apache.poi.ss.usermodel.row;import org.apache.poi.ss.usermodel.sheet;import org.apache.poi.ss.usermodel.workbook;import org.apache.poi.xssf.streaming.sxssfworkbook;import org.apache.poi.xssf.usermodel.xssfworkbook;import java.lang.reflect.field;import java.lang.reflect.method;import java.util.list;/** * @author fc * @date 2018-09-18 * @msg 反射工具类 * @tips 字段必须使用@allow注解 title属性定义标题 */public class excelcreateutil { /** * * @param o object是vo类 * @param suf 返回的excel文件后缀 * @return * @throws exception */ public static workbook createworkbook(list<object> o,returnsuf suf) throws exception { //定义一个新的工作簿 workbook wb = suf.getvalue().equals(returnsuf.xlsx.getvalue())?new xssfworkbook():new hssfworkbook(); //创建sheet sheet sheet = wb.createsheet(string.valueof(system.currenttimemillis())); //创建行 row row = sheet.createrow(0); //第一行以注解@allow title属性命名 class<?> aclass = o.get(0).getclass(); field[] fields1 = aclass.getdeclaredfields(); int bj2 = 0; for (int j = 0; j < fields1.length; j++) { allow annotation = fields1[j].getannotation(allow.class); if (annotation != null) { fields1[j].setaccessible(true); row.createcell(bj2).setcellvalue(annotation.title()); bj2++; } } int bj1 = 1; for (int i = 0; i < o.size(); i++) { //获取当前对象 object o1 = o.get(i); //获取当前类类型 class<?> c = o.get(i).getclass(); //获取当前类类型的所有属性 field[] fields = c.getdeclaredfields(); //创建行-从第二行起 row row1 = sheet.createrow(bj1); bj1++; int bj = 0; for (int j = 0; j < fields.length; j++) { allow annotation = fields1[j].getannotation(allow.class); if (annotation != null) { fields[j].setaccessible(true); //得到属性名 string name = fields[j].getname(); //获取属性对应的get方法 method method = c.getdeclaredmethod(toget(name)); object invoke = method.invoke(o1); string value = invoke == null ? "" : invoke.tostring(); //赋值 row1.createcell(bj).setcellvalue(value); bj++; } } } return wb; } //获取属性的set方法 public static string toset(string s) { final string set = "set"; if (character.isuppercase(s.charat(0))) { return set + s; } else { return set + (new stringbuilder()).append(character.touppercase(s.charat(0))).append(s.substring(1)).tostring(); } } //获取属性的get方法 public static string toget(string s) { final string get = "get"; if (character.isuppercase(s.charat(0))) { return get + s; } else { return get + (new stringbuilder()).append(character.touppercase(s.charat(0))).append(s.substring(1)).tostring(); } } public enum returnsuf { xls(".xls后缀", ".xls"), /** *大数据量建议使用.xlsx */ xlsx(".xlsx后缀", ".xlsx"),; private string key; private string value; returnsuf(string key, string value) { this.key = key; this.value = value; } public string getkey() { return key; } public void setkey(string key) { this.key = key; } public string getvalue() { return value; } public void setvalue(string value) { this.value = value; } }}
以上就是java反射工具类的实现代码（excel导出）的详细内容。