Java uses POI for Excel table generation

Using the POI technology to generate Excel, use reflection technology to implement automatic mapping of the data in the list.

Exporttableutil.java

public class Exporttableutil {/** * * @Description: Get a CSV-formatted string * @param @param header * @param @param fieldnamelist corresponding property name corresponding to the table header and the value to the data type's property name * @param @param params data * @param @return * @param @throws illegalargumentexception * @param @thr oWS illegalaccessexception * @param @throws nosuchfieldexception * @param @throws securityexception settings file * @return String return type */public static String csv (string[] headlist, string[] fieldnamelist, list<?> params) throws Illegalargumentex Ception, Illegalaccessexception,nosuchfieldexception, SecurityException {StringBuilder StringBuilder = new StringBuilder ();//Add head on firstfor (int i = 0; null! = Headlist && i < headlist.length; i++) {Stringbuilde R.append (Headlist[i]), if (I < headlist.length-1) {stringbuilder.append (",");} else {stringbuilder.append ("\ r \ n");}} Add data from second line to---for (int i = 0; null! = params && i < params.size (); i++) {class<? extend s object> clazz = Params.get (i). Getclass (); for (int j = 0; Null! = Fieldnamelist && J < Fieldnamelist.length; J + +) {String FieldName = fieldnamelist[j ];if (!fieldname.contains (".")) {Field field = Clazz.getdeclaredfield (FieldName); if (null! = Field) {field.setaccessible (true); Object obj = Field.get ( Params.get (i)); if (null! = obj) {stringbuilder.append (obj.tostring ());}} else {stringbuilder.append ("");} if (J < fieldnamelist.length-1) {stringbuilder.append (",");}} Else{object param = Params.get (i), Object valobj = Vectorobj (clazz, FieldName, param); if (null!=valobj) { Stringbuilder.append (Valobj.tostring ());} else {stringbuilder.append ("");} if (J < fieldnamelist.length-1) {stringbuilder.append (",");}}} Stringbuilder.append ("\ r \ n");} return stringbuilder.tostring ();} /** * * @Description: Download documents via response * @param @param response * @param @param fileName * @param @param headlist * @param  @param fieldnamelist * @param @param params settings file * @return void return type */public static void Httpexportcsv (HttpServletRequest Request, httpservletresponse response, String fileName, string[] headlist,string[] fieldnamelist, list<?> params) {Map <string, object> map = new hashmap<string, object> (); try {response.setcharacterencoding ("UTF-8"); Response.setcontenttype ("Application/x-download"); final String useragent = Request.getheader ("user-agent"); String csvcontent = CSV (headlist, fieldnamelist, params); String finalfilename = null;if (Stringutils.contains (useragent, "MSIE")) {//IE browser finalfilename = Urlencoder.encode ( FileName, "UTF8");} else if (Stringutils.contains (useragent, "Mozilla")) {//Google, Firefox finalfilename = new String (Filename.getbytes (), " Iso8859-1 ");} else {finalfilename = Urlencoder.encode (FileName, "UTF8");//Other Browser}response.setheader ("Content-disposition", " Attachment Filename=\ "" + finalfilename + "\" "); Response.getoutputstream (). Write (Csvcontent.getbytes ());} catch (IllegalArgumentException | illegalaccessexception | nosuchfieldexception | SecurityException | IOException e) {E.printStackTrace (); Map.put ("State", "202"), Map.put ("message", "Data Conversion exception"), try {response.getoutputstream (). Write ( Jsonutils.tojsonstring (map). GetBytes ());} catch (IOException E1) {//TODO auto-generated catch Blocke1.printstacktrace ();}}} /** * * @Description: Get the binary stream of Excel table * @param @param headlist header * @param @param fieldnamelist property name corresponds to the header order and must exist in the data type Name corresponds to * @param @param params * @param @return * @param @throws illegalargumentexception * @param @throws Illegalaccessexce  Ption * @param @throws nosuchfieldexception * @param @throws SecurityException * @param @throws ioexception settings file * @return Byte[] return type */public static byte[] xls (string[] headlist, string[] fieldnamelist, list<?> params) throws Illegalarg Umentexception, Illegalaccessexception,nosuchfieldexception, SecurityException, IOException {Workbook work = new Hssfworkbook (); Sheet Sheet = Work.createsheet (); Row rowone = sheet.createrow (0); for (int i = 0; null! = Headlist && i < headlist.length; i++) {//Header cell CellOn E = Rowone.createcell (i); Cellone.setcellvalue (Headlist[i]);//Fill value}//data fill for (int i = 0; null! = params && i < P Arams.size (); i++) {class<? extends object> clazz = Params.get (i). GetClass (); Row DataRow = Sheet.createrow (i + 1); for (int j = 0; Null! = Fieldnamelist && J < Fieldnamelist.length; J + +) {S Tring fieldName = Fieldnamelist[j]; Cell cell = Datarow.createcell (j); if (!fieldname.contains (".")) {Field field = Clazz.getdeclaredfield (FieldName); field.setaccessible (true); Object obj = Field.get (Params.get (i)); if ( Null! = obj) {if (obj instanceof String) {Cell.setcellvalue (obj.tostring ());} else if (obj instanceof Double) {Cell.setcel LValue (double) obj); else if (obj instanceof Boolean) {cell.setcellvalue ((Boolean) obj),} else if (obj instanceof Date) {Cell.setcellvalue (Dat e) obj);} else {Cell.setcellvalue (obj.tostring ());}}} else if (Fieldname.contains (".")) {Object param = params.get (i); object valobj = Vectorobj (clazz, FieldName, param); Cell.setcellvalue (nulL = = valobj? Null:valObj.toString ());}}} Byteoutputstream BOS = new Byteoutputstream (); Work.write (BOS); Work.close (); return bos.getbytes ();} private static Object vectorobj (class<? extends Object> Clazz, String fieldName, Object obj) throws Nosuchfieldexcep tion, securityexception,illegalargumentexception, illegalaccessexception {if (!fieldname.contains (".")) {Field field = Clazz.getdeclaredfield (FieldName); field.setaccessible (true); return Field.get (obj);} else {String fieldchildname = fieldname.substring (0, Fieldname.indexof (".")); O Bject NEWOBJ = null;if (null! = fieldchildname) {Field field = Clazz.getdeclaredfield (Fieldchildname); Field.setaccessible (true); newObj = Field.get (obj), if (NEWOBJ = = null) {return null;} else {class<? extends object> C LAZZ2 = Newobj.getclass (); String fieldotherchildname = fieldname.substring (Fieldname.indexof (".") + 1); return Vectorobj (CLAZZ2, Fieldotherchildname, NEWOBJ);}} return null;}} /** * * @Description: Export xls table-------------start with the first column * @param @Param request * @param @param response * @param @param filename * @param @param headlist header * @param @param fieldnamel The Ist property name is the same as the property name of the object type in the data list, corresponding to the order of the table header * @param @param params settings file * @return void return type */public static void Httpexportxls (H Ttpservletrequest request, HttpServletResponse response, String fileName, string[] headlist,string[] fieldnamelist, list<?> params) {map<string, object> Map = new hashmap<string, object> (); try { Response.setcharacterencoding ("UTF-8"); Response.setcontenttype ("Application/x-download"); final String useragent = Request.getheader ("User-agent"); byte[] xlscontent = xls (headlist, fieldnamelist, params); String finalfilename = null;if (Stringutils.contains (useragent, "MSIE")) {//IE browser finalfilename = Urlencoder.encode ( FileName, "UTF8");} else if (Stringutils.contains (useragent, "Mozilla")) {//Google, Firefox finalfilename = new String (Filename.getbytes (), " Iso8859-1 ");} else {finalfilename = Urlencoder.encode (FileName, "UTF8");//Other browsers}responSe.setheader ("Content-disposition", "attachment; Filename=\ "" + finalfilename + "\" "); Response.getoutputstream (). write (xlscontent);} catch (IllegalArgumentException | illegalaccessexception | nosuchfieldexception | SecurityException | IOException e) {e.printstacktrace (); Map.put ("State", "202"); Map.put ("Message", "Data Conversion exception"); try { Response.getoutputstream (). Write (jsonutils.tojsonstring (map). GetBytes ());} catch (IOException E1) {//TODO auto-generated catch Blocke1.printstacktrace ();}}} /** * * @Description: Export the corresponding file according to the suffix name of the path * @param @param request * @param @param response * @param @param fileName---------- --File name (format *.xls,*.csv) * @param @param headlist--------------table header content * @param @param Fieldnamelist----------property names are the same as the names of the types in the data list, and are mapped by sequential and table headers. * @param @param params--------------data * @param @throws Exception----file name is not valid * @return void return type */public static void http Export (HttpServletRequest request, httpservletresponse response, String fileName, string[] headlist,string[] Fieldnamelist, list<?&Gt params) throws Exception {if (null = = FileName | | Stringutils.isempty (filename) {throw new NullPointerException ("file name cannot be empty");} else {String suffix = filename.substring ( Filename.indexof (".") + 1); if (null! = suffix) {System.out.println (suffix); switch (suffix) {case "CSV": Httpexportcsv ( Request, response, FileName, headlist, fieldnamelist, params) break;case "xls": Httpexportxls (Request, Response, FileName, headlist, fieldnamelist, params), break;case "xlsx": Httpexportxls (Request, Response, FileName, Headlist, Fieldnamelist, params); Break;case "Doc": Break;case "docx": Break;case "PDF": Break;}} else {throw new Exception ("The format of the file name is not valid");}}}

　　

Java uses POI for Excel table generation