本文介绍了一个用于处理CSV文件的Java工具类，该类提供了一系列通用方法，包括读取、写入和解析CSV文档，方便开发者在项目中进行数据操作。
package cn.com.test.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* 自定义注解
* @author： Rodge
* @time： 2017年12月25日 下午9:39:18
* @version： V1.0.0
*/
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface CSVField {
/**
* CSV文件列名
*/
public String name() default "";
}
csv工具类
package cn.com.javatest.utils;
import java.io.File;
import java.io.FileInputStream;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.nio.charset.Charset;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.time.DateFormatUtils;
import org.apache.commons.lang3.time.DateUtils;
import org.apache.log4j.Logger;
import org.springframework.util.ReflectionUtils;
import com.csvreader.CsvReader;
import com.csvreader.CsvWriter;
import cn.com.javatest.annotation.CSVField;
/**
* CSV工具类
*
* @author： Rodge
* @time： 2017年12月25日 下午10:02:08
* @version： V1.0.0
*/
public final class CSVUtils {
/** 日志对象 **/
private static final Logger LOGGER = Logger.getLogger(CSVUtils.class);
/** 临时文件**/
private static final String TEMP_PATH = "temp.csv";
/** 私有无参构造方法 **/
private CSVUtils() { }
/**
* 生成CSV文件
*
* @param filePath 文件保存路径，例如：D:/temp/test.csv
* @param beans 实体对象集合
*/
public static <T> void createCSVFile(String filePath, List<T> beans) {
CsvWriter writer = null;
try {
// 创建文件目录
createDir(filePath);
// 生成文件
writer = new CsvWriter(filePath, ',', Charset.forName("GBK"));
// 获取内容
List<String[]> contents = getStringArrayFromBean(beans);
// 写入内容
for (String[] each : contents) {
writer.writeRecord(each, true);
}
} catch (Exception e) {
LOGGER.error("生成CSV文件失败", e);
} finally {
if (writer != null) {
writer.close();
}
}
}
/**
* 导出CSV文件
*
* @param request 请求对象
* @param response 响应对象
* @param beans 实体对象集合
*/
public static <T> void exportCSVFile(HttpServletRequest request, HttpServletResponse response, List<T> beans) {
String path = request.getServletContext().getRealPath("/");
try (FileInputStream input = new FileInputStream(createFile(path + TEMP_PATH))) {
// 生成文件
CsvWriter writer = new CsvWriter(path + TEMP_PATH, ',', Charset.forName("GBK"));
// 获取内容
List<String[]> contents = getStringArrayFromBean(beans);
// 写入内容
for (String[] each : contents) {
writer.writeRecord(each, true);
}
writer.close();
// 导出文件
ServletOutputStream output = response.getOutputStream();
// 以当前时间作为文件名
String fileName = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date());
response.setContentType("application/csv;charset=UTF-8");
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Expose-Headers", "*");
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8") + ".csv");
int len = -1;
byte[] b = new byte[1024 * 1024];
while((len = input.read(b)) != -1) {
output.write(b, 0, len);
}
output.close();
} catch (Exception e) {
LOGGER.error("导出CSV文件失败", e);
} finally {
deleteFile(path, TEMP_PATH);
}
}
/**
* 导出CSV文件
*
* @param request 请求对象
* @param response 响应对象
* @param beans 实体对象集合
* @param fileName 文件名称 ,如：测试名称
*/
public static <T> void exportCSVFile(HttpServletRequest request, HttpServletResponse response, List<T> beans, String fileName) {
String path = request.getServletContext().getRealPath("/");
try (FileInputStream input = new FileInputStream(createFile(path + TEMP_PATH))) {
// 生成文件
CsvWriter writer = new CsvWriter(path + TEMP_PATH, ',', Charset.forName("GBK"));
// 获取内容
List<String[]> contents = getStringArrayFromBean(beans);
// 写入内容
for (String[] each : contents) {
writer.writeRecord(each, true);
}
writer.close();
// 导出文件
ServletOutputStream output = response.getOutputStream();
response.setContentType("application/csv;charset=UTF-8");
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Expose-Headers", "*");
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8") + ".csv");
int len = -1;
byte[] b = new byte[1024 * 1024];
while((len = input.read(b)) != -1) {
output.write(b, 0, len);
}
output.close();
} catch (Exception e) {
LOGGER.error("导出CSV文件失败", e);
} finally {
deleteFile(path, TEMP_PATH);
}
}
/**
* 导出CSV模板
*
* @param request 请求对象
* @param response 响应对象
* @param beans 实体对象集合
*/
public static <T> void exportCSVTemplate(HttpServletRequest request, HttpServletResponse response, Class<T> clazz) {
// 以当前时间作为文件名
String fileName = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date());
exportCSVTemplate(request, response, clazz, fileName);
}
/**
* 导出CSV模板
*
* @param request 请求对象
* @param response 响应对象
* @param beans 实体对象集合
* @param fileName 文件名称
*/
public static <T> void exportCSVTemplate(HttpServletRequest request, HttpServletResponse response, Class<T> clazz, String fileName) {
String path = request.getServletContext().getRealPath("/");
try (FileInputStream input = new FileInputStream(createFile(path + TEMP_PATH))) {
// 生成文件
CsvWriter writer = new CsvWriter(path + TEMP_PATH, ',', Charset.forName("GBK"));
// 筛选出标有注解的字段
Field[] declaredFields = clazz.getDeclaredFields();
List<Field> annoFields = new ArrayList<Field>();
for (Field field : declaredFields) {
CSVField anno = field.getAnnotation(CSVField.class);
if (anno != null) {
annoFields.add(field);
}
}
// 获取注解的值，即内容标题
String[] title = new String[annoFields.size()];
for (int i = 0; i < annoFields.size(); i++) {
title[i] = annoFields.get(i).getAnnotation(CSVField.class).name();
}
// 写入内容
if (ArrayUtils.isNotEmpty(title)) {
writer.writeRecord(title);
}
writer.close();
// 导出文件
ServletOutputStream output = response.getOutputStream();
response.setContentType("application/csv;charset=UTF-8");
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Expose-Headers", "*");
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8") + ".csv");
int len = -1;
byte[] b = new byte[1024 * 1024];
while((len = input.read(b)) != -1) {
output.write(b, 0, len);
}
output.close();
} catch (Exception e) {
LOGGER.error("导出CSV模板失败", e);
} finally {
deleteFile(path, TEMP_PATH);
}
}
/**
* 读取CSV文件内容
*
* @param filePath 文件存放的路径，如：D:/csv/xxx.csv
* @param bean 类类型
* @return List<T>
*/
public static <T> List<T> readCSVFile(String filePath, Class<T> bean) {
List<String[]> dataList = new ArrayList<String[]>();
CsvReader reader = null;
try {
// 创建CSV读对象 例如:CsvReader(文件路径，分隔符，编码格式);
reader = new CsvReader(filePath, ',', Charset.forName("GBK"));
if (reader != null) {
// 跳过表头，如果需要表头的话，这句可以忽略
//reader.readHeaders();
// 逐行读入除表头的数据
while (reader.readRecord()) {
dataList.add(reader.getValues());
}
if (!dataList.isEmpty()) {
// 数组转对象
return getBeanFromStringArray(dataList, bean);
}
}
} catch (Exception e) {
LOGGER.error("读取CSV文件失败", e);
} finally {
if (reader != null) {
reader.close();
}
}
return Collections.emptyList();
}
/**
* 删除该目录下所有文件
*
* @param filePath 文件目录路径，如：d:/test
*/
public static boolean deleteFiles(String filePath) {
File file = new File(filePath);
if (file.exists()) {
File[] files = file.listFiles();
if (files != null && files.length > 0) {
for (File f : files) {
if (f.isFile() && f.delete()) {
LOGGER.info("删除" + f.getName() + "文件成功");
}
}
return true;
}
}
return false;
}
/**
* 删除单个文件
*
* @param filePath 文件目录路径，如：d:/test
* @param fileName 文件名称，如：110.csv
*/
public static boolean deleteFile(String filePath, String fileName) {
File file = new File(filePath);
if (file.exists()) {
File[] files = file.listFiles();
if (files != null && files.length > 0) {
for (File f : files) {
if (f.isFile() && f.getName().equals(fileName)) {
return f.delete();
}
}
}
}
return false;
}
/**
* 泛型实体转换为数组
*
* @param beans 实体类集合
* @return List<String[]>
*/
private static <T> List<String[]> getStringArrayFromBean(List<T> beans) {
List<String[]> result = new ArrayList<String[]>();
Class<? extends Object> cls = beans.get(0).getClass();
Field[] declaredFields = cls.getDeclaredFields();
List<Field> annoFields = new ArrayList<Field>();
// 筛选出标有注解的字段
for (Field field : declaredFields) {
CSVField anno = field.getAnnotation(CSVField.class);
if (anno != null) {
annoFields.add(field);
}
}
// 获取注解的值，即内容标题
String[] title = new String[annoFields.size()];
for (int i = 0; i < annoFields.size(); i++) {
title[i] = annoFields.get(i).getAnnotation(CSVField.class).name();
}
result.add(title);
try {
// 获取内容
for (T t : beans) {
String[] item = new String[annoFields.size()];
int index = 0;
for (Field field : annoFields) {
Class<?> valType = field.getType();
String fieldName = field.getName();
String methodName = "get" + fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1);
Method method = ReflectionUtils.findMethod(t.getClass(), methodName);
if (method != null) {
Object value = ReflectionUtils.invokeMethod(method, t);
item[index] = setValues(value, valType);
}
index ++;
}
result.add(item);
}
} catch (Exception e) {
LOGGER.info("实体对象转数组失败", e);
}
return result;
}
/**
* 数组转为对象集合
*
* @param dataList 集合数据
* @param bean 类类型
* @return List<T>
*/
private static <T> List<T> getBeanFromStringArray(List<String[]> dataList, Class<T> bean) {
List<T> list = new ArrayList<>();
List<Map<String, String>> titles = getTitles(dataList);
Map<String, Field> fields = getFields(bean);
try {
for (Map<String, String> map : titles) {
T t = bean.newInstance();
for (Entry<String, String> entry : map.entrySet()) {
if (fields.containsKey(entry.getKey())) {
Field field = fields.get(entry.getKey());
Class<?> valType = field.getType();
Object value = getType(entry.getValue(), valType);
String fieldName = field.getName();
String methodName = "set" + fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1);
Method method = ReflectionUtils.findMethod(bean, methodName, valType);
if (method != null) {
ReflectionUtils.invokeMethod(method, t, value);
}
}
}
list.add(t);
}
} catch (Exception e) {
LOGGER.error("创建实体失败", e);
}
return list;
}
/**
* 数组标题与值的对应关系
*
* @param dataList 集合数据
* @return
*/
private static <T> List<Map<String, String>> getTitles(List<String[]> dataList) {
List<Map<String, String>> list = new ArrayList<>();
String[] titles = dataList.get(0);
dataList.remove(0);
for (String[] values : dataList) {
Map<String, String> titleMap = new HashMap<>();
for (int i = 0; i < values.length; i++) {
titleMap.put(titles[i], values[i]);
}
list.add(titleMap);
}
return list;
}
/**
* 注解名称与字段属性的对应关系
*
* @param clazz 实体对象类类型
* @param <T> 泛型类型
* @return Map<String,Field>
*/
private static <T> Map<String, Field> getFields(Class<T> clazz) {
Map<String, Field> annoMap = new HashMap<>();
Field[] fileds = clazz.getDeclaredFields();
for (Field filed : fileds) {
CSVField anno = filed.getAnnotation(CSVField.class);
if (anno != null) {
// 获取name属性值
if (StringUtils.isNotBlank(anno.name())) {
annoMap.put(anno.name(), filed);
}
}
}
return annoMap;
}
/**
* 转换值
*
* @param value 属性值
* @param valType 属性类型
* @return
*/
private static String setValues(Object value, Class<?> valType) {
if (value == null) {
return "";
} else if (valType == Date.class) {
// 默认日期类型格式：yyyy-MM-dd HH:mm:ss
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return sdf.format(((Date) value).getTime());
} else { // 字符串
return String.valueOf(value);
}
}
/**
* 转换成实体属性对应的类型
*
* @param value 每一格的数值
* @param valType 实体属性类型
* @return Object 转换为对应类型以obj返回
*/
private static <T> Object getType(String value, Class<T> valType) {
try {
if (valType == Date.class) {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return sdf.parse(value);
} else if (valType == Double.class) {
return Double.parseDouble(value);
} else if (valType == BigDecimal.class) {
return new BigDecimal(value);
} else if (valType == Integer.class) {
return Integer.parseInt(value);
} else if (valType == Long.class) {
return Long.parseLong(value);
} else if (valType == Boolean.class) {
return Boolean.parseBoolean(value);
}
} catch (Exception e) {
LOGGER.error("类型转换异常", e);
}
return value;
}
/**
* 创建文件目录
*
* @param filePath 文件路径，例如：temp/test.csv
*/
private static void createDir(String filePath) {
try {
File file = new File(filePath.substring(0, filePath.lastIndexOf('/')));
if (!file.exists()) {
file.mkdirs();
}
} catch (Exception e) {
LOGGER.error("创建文件目录失败", e);
}
}
/**
* 创建文件
*
* @param filePath 文件路径，例如：temp/test.csv
* @return File
*/
private static File createFile(String filePath) {
try {
File file = new File(filePath);
if (!file.exists()) {
file.createNewFile();
}
return file;
} catch (Exception e) {
LOGGER.error("创建文件失败", e);
}
return null;
}
}
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