JavaBean中数据写入文件工具类

  1 import java.beans.PropertyDescriptor;
  2 import java.io.BufferedReader;
  3 import java.io.BufferedWriter;
  4 import java.io.File;
  5 import java.io.FileInputStream;
  6 import java.io.IOException;
  7 import java.io.InputStream;
  8 import java.io.InputStreamReader;
  9 import java.io.Writer;
 10 import java.lang.reflect.Field;
 11 import java.lang.reflect.Method;
 12 import java.util.ArrayList;
 13 import java.util.List;
 14 
 15 import org.apache.commons.io.output.FileWriterWithEncoding;
 16 
 17 import com.genilex.gRule.ocr.dto.DrivingLicense;
 18 
 19 public class FileUtil {
 20     private FileUtil(){}
 21     
 22     /**
 23      * 实体类数据写入文件中
 24      * @param <T>
 25      * @param t 实体类
 26      * @param fileName 文件名（带后缀）
 27      * @param fileDir 文件夹路径，不包括文件名及后缀
 28      * @return
 29      */
 30     public static <T> boolean beanToFile(T t,String fileName,String fileDir){
 31         boolean bl = false;
 32         try {
 33             //取得类中所有属性
 34             Class clazz = t.getClass();
 35             Field[] fields = clazz.getDeclaredFields();
 36             
 37             //判断文件夹是否存在，不存在则创建
 38             File fileDir2 = new File(fileDir);
 39             if(!fileDir2.exists()){
 40                 fileDir2.mkdirs();
 41             }
 42             //文件
 43             File file = new File(fileDir,fileName);
 44             
 45             //需要封装的list
 46             List<String> list = new ArrayList<String>();
 47             //header数组，用来设置数据字符串，使其一一按顺序对应
 48             String[] titles = null;
 49             if(!file.exists()){//如果文件不存在，则创建文件并加header
 50                 //header字符串设置
 51                 StringBuilder titleStr = new StringBuilder();
 52                 for (int i = 0; i < fields.length; i++) {
 53                     if(i > 0){
 54                         titleStr.append(",");
 55                     }
 56                     titleStr.append(fields[i].getName());
 57                 }
 58                 list.add(titleStr.toString());
 59                 
 60                 titles = titleStr.toString().split(",");
 61             }else{//如果文件存在，则继续追加数据
 62                 //读取文件第一行获得header
 63                 titles = readFirstLine(file).replace("\"","").split(",");
 64             }
 65             //封装数据字符串，与header按顺序对于设置
 66             list.add(beanToStr(t,titles,clazz));
 67             bl = listToFile(list,file);
 68         } catch (Exception e) {
 69             e.printStackTrace();
 70         }
 71         return bl;
 72     }
 73     
 74     /**
 75      * 根据传入的key数组设置bean中数据，按key的顺序封装成字符串
 76      * @param obj javaBean
 77      * @param keys 列名数组
 78      * @param clazz Class
 79      * @return
 80      */
 81     public static String beanToStr(Object obj,String[] titles,Class<?> clazz){
 82         try {
 83             StringBuilder sb = new StringBuilder();
 84             
 85             for (int i = 0; i < titles.length; i++) {
 86                 PropertyDescriptor pd = new PropertyDescriptor(titles[i], clazz);
 87                 //得到get方法
 88                 Method method = pd.getReadMethod();
 89                 //执行get方法
 90                 Object value = method.invoke(obj);
 91                 if(i > 0){
 92                     sb.append(",");
 93                 }
 94                 //封装数据，用","隔开
 95                 sb.append(value != null ? String.valueOf(value) : "");
 96             }
 97             return sb.toString();
 98         } catch (Exception e) {
 99             e.printStackTrace();
100             return null;
101         }
102     }
103     
104     /**
105      * 读取文件第一行
106      * @param file
107      * @return
108      */
109     public static String readFirstLine(File file){
110         String res = null;
111         
112         InputStream is = null;
113         BufferedReader buffer = null;
114         try {
115             is = new FileInputStream(file);
116             buffer = new BufferedReader(new InputStreamReader(is,"UTF-8"));
117             
118             res = buffer.readLine();
119         } catch (Exception e) {
120             e.printStackTrace();
121         }finally{
122             if(buffer != null){
123                 try {
124                     buffer.close();
125                 } catch (IOException e) {
126                     e.printStackTrace();
127                     buffer = null;
128                 }
129             }
130             if(is != null){
131                 try {
132                     is.close();
133                 } catch (IOException e) {
134                     e.printStackTrace();
135                     is = null;
136                 }
137             }
138         }
139         return res;
140     }
141     
142     /**
143      * list 写入文件
144      * @param list
145      * @param file
146      * @return
147      */
148     public static boolean listToFile(List<String> list,File file){
149         boolean bl = true;
150         
151         Writer writer = null;
152         BufferedWriter buffer = null;
153         try {
154             writer = new FileWriterWithEncoding(file,"UTF-8",true);
155             buffer = new BufferedWriter(writer);
156             
157             if(list != null && !list.isEmpty()){
158                 for (String str : list) {
159                     buffer.write(str);
160                     buffer.newLine();
161                 }
162             }
163         } catch (Exception e) {
164             e.printStackTrace();
165             bl = false;
166         }finally{
167             if(buffer != null){
168                 try {
169                     buffer.close();
170                 } catch (IOException e) {
171                     e.printStackTrace();
172                     buffer = null;
173                 }
174             }
175             if(writer != null){
176                 try {
177                     writer.close();
178                 } catch (IOException e) {
179                     e.printStackTrace();
180                     writer = null;
181                 }
182             }
183         }
184         return bl;
185     }
186     
187     public static void main(String[] args) {
188         DrivingLicense dl = new DrivingLicense();
189         dl.setVin("你");
190         dl.setAddress("好");
191         dl.setEngineNo("啊");
192         
193         beanToFile(dl, "xingshizheng.csv", "D:\\xingshizeng");
194     }
195 }