java网页导出excel类 WebExcelUtil

定义：

package util;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.util.*;

/**
 * Created by gcy
 */
public class WebExcelUtil {
    private HttpServletResponse response;
    private LinkedHashMap<String, String> header;
    private List<LinkedHashMap<String, Object>> list;
    private List<Map<String, Object>> maplist;
    private OnItem onItem ;

    /**
     * 定义内部项处理事件，可传入：匿名函数、lambada或继承接口类
     */
    public interface OnItem {
        String event(String key,Object value,Map<String, Object> row);
    }

    private StringBuilder content;
    public WebExcelUtil(){}
    public WebExcelUtil(HttpServletResponse response, LinkedHashMap<String, String> header, List<LinkedHashMap<String, Object>> list){
        this.response = response;
        this.header = header;
        this.list = list;
    }

    public static WebExcelUtil CreateInstance(HttpServletResponse response,LinkedHashMap<String, String> header, List<Map<String, Object>> maplist){
       WebExcelUtil entity = new WebExcelUtil();
        entity.response = response;
        entity.header = header;
        entity.maplist = maplist;
        return entity;
    }
    public void writeFile(String fileName){
        writeFile(fileName,null);
    }
    public void writeFile(String fileName,OnItem onItem){
        try {
            createContentString(onItem);
            response.setCharacterEncoding("utf-8");
            response.setHeader("contentType", "application/vnd.ms-excel");
            try {
                response.setHeader("Content-disposition", "attachment; filename="
                        + new String(fileName.getBytes("UTF-8"), "ISO_8859_1")
                );
                Writer out = response.getWriter();
                out.write(content.toString());
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        catch (Exception ex){
             ex.printStackTrace();
        }
    }

    private void createContentString(OnItem onItem){
        if (header!=null && header.size()>0){
            content = new StringBuilder();
            content.append("<table border='1'>");
            content.append("<tr>");
            List<String> listHeader = new ArrayList<String>();
            for(Map.Entry<String,String> entry : header.entrySet()){
                content.append("<th>"+entry.getValue()+"</th>");
                listHeader.add(entry.getKey());
            }
            content.append("</tr>");

            if (list!=null && list.size()>0){
                for(Map<String, Object> item : list){
                    content.append("<tr>");
                    for(String head : listHeader){
                        if (onItem!=null)
                            content.append("<td>"+onItem.event(head,item.get(head),item)+"</td>");
                        else
                            content.append("<td>"+item.get(head)+"</td>");
                    }
                    content.append("</tr>");
                }
            }
            else if (maplist!=null && maplist.size()>0){
                for(Map<String, Object> item : maplist){
                    content.append("<tr>");
                    for(String head : listHeader){
                        if (onItem!=null)
                            content.append("<td>"+onItem.event(head,item.get(head),item)+"</td>");
                        else
                            content.append("<td>"+item.get(head)+"</td>");
                    }
                    content.append("</tr>");
                }
            } {

            }
            content.append("</table>");
        }
    }

}

使用：

List<Map<String, Object>> list = schoolsTeacherService.listSchool(param);
        LinkedHashMap<String, String> header = new LinkedHashMap<String, String>() {
            {
                put("id","id");
                put("schoolName","学校名称");
                put("alias","别名");
                put("schoolType","学段");
                put("provinceName","省份");
                put("cityName","城市");
                put("isElite","是否名校");
                put("levels","名校等级");
                put("createTime","创建时间");
                put("updateTime","修改时间");
            }
        };
        
        WebExcelUtil webExcelUtil = WebExcelUtil.CreateInstance(response,header,list);
        webExcelUtil.writeFile("学校列表" + DateUtil.getCurrentDateTimeToSimpleString() + ".xls",
            (key,value,row)->{//lambda表达式

                int val ;
                String ret ;
                if (key.equalsIgnoreCase("schoolType")) {
                    val =(value==null?0:Integer.parseInt(value.toString()));
                    switch (val){
                        case 1: ret = "小学";break;
                        case 2: ret = "初中";break;
                        case 3: ret = "高中";break;
                        default:ret = "其他";break;
                    }
                }else if (key.equalsIgnoreCase("isElite")) {
                    val =(value==null?0:Integer.parseInt(value.toString()));
                    switch (val){
                        case 1: ret = "名校";break;
                        default:ret = "非名校";break;
                    }
                }
                else {
                    ret = (value==null?"":value.toString());
                }
                return ret;
            }
        );