读写csv文件——考虑各种异常场景，源码

　　CSV是以逗号间隔的文本文件，其文件以纯文本形式存储表格数据（数字和文本）。在JAVA中可以通过输出文件流的方式将数据写入CSV文件，通过BufferedReader类去读该路径中的文件，使用readLine方法进行逐行读取。

• 　　写csv文件需要注意：

　　1、如果需要重复写文件，需要考虑删除已经存在的文件。

• 　　读csv文件需要注意：

　　1、文件路径是否存在

　　2、文件表头是否正确，考虑兼容性问题时，只需要考虑是否存在需要的列即可

第一步：创建一个对象类

 package testCSV;

 public class Person {
     private String id;
     private String name;
     private String sex;
     private int age;

     public Person() {
     }

     public Person(String id, String name, String sex, int age) {
         this.id = id;
         this.name = name;
         this.sex = sex;
         this.age = age;
     }

     public String getId() {
         return id;
     }

     public void setId(String id) {
         this.id = id;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public String getSex() {
         return sex;
     }

     public void setSex(String sex) {
         this.sex = sex;
     }

     public int getAge() {
         return age;
     }

     public void setAge(int age) {
         this.age = age;
     }
 }

第二步：写和读csv文件

 package testCSV;

 import java.io.*;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.UUID;

 public class FileCsv {
     private static final String fileName = "D:\\workspace\\tmp\\obj.csv";
     private static final String CSV_SPLIT = ",";
     private static int idIndex = -1;
     private static int nameIndex = -1;
     private static int sexIndex = -1;
     private static int ageIndex = -1;

     /**
      * 生成uuid
      *
      * @return 32位uuid
      */
     private static String getUUID32() {
         return UUID.randomUUID().toString().replace("-", "").toLowerCase();
     }

     /**
      * 构造数据
      *
      * @return 数据
      */
     private static List<Person> buildData() {
         List<Person> personList = new ArrayList<Person>(10);
         personList.add(new Person(getUUID32(), "张三", "female", 26));
         personList.add(new Person(getUUID32(), "李四", "man", 34));
         personList.add(new Person(getUUID32(), "王五", "female", 55));
         personList.add(new Person(getUUID32(), "一一", "female", 11));
         return personList;
     }

     /**
      * 写csv文件
      *
      * @return 文件名
      */
     public static String writeCsv() {
         File file = new File(fileName);
         if (null != file && file.exists()) {
             file.delete();
         }
         List<Person> personList = buildData();
         FileOutputStream out = null;
         OutputStreamWriter osw = null;
         BufferedWriter bw = null;
         try {
             out = new FileOutputStream(file);
             osw = new OutputStreamWriter(out, "UTF-8");
             bw = new BufferedWriter(osw);
             String title = "ID,NAME,SEX,AGE\r";
             bw.append(title);

             for (Person data : personList) {
                 bw.append(data.getId());
                 bw.append(CSV_SPLIT);
                 bw.append(data.getName());
                 bw.append(CSV_SPLIT);
                 bw.append(data.getSex());
                 bw.append(CSV_SPLIT);
                 bw.append(String.valueOf(data.getAge()));
                 bw.append("\r");
             }
         }
         catch (Exception e) {
             e.printStackTrace();
         }
         finally {
             if (bw != null) {
                 try {
                     bw.close();
                 }
                 catch (IOException e) {
                     e.printStackTrace();
                 }
             }
             if (osw != null) {
                 try {
                     osw.close();
                 }
                 catch (IOException e) {
                     e.printStackTrace();
                 }
             }
             if (out != null) {
                 try {
                     out.close();
                 }
                 catch (IOException e) {
                     e.printStackTrace();
                 }
             }
         }
         return fileName;
     }

     /**
      * 表头正确性校验
      *
      * @param titleInfo 表头
      * @return
      */
     private static Boolean checkTitle(String titleInfo) {
         if (null == titleInfo || titleInfo.isEmpty()) {
             return false;
         }
         String[] titles = titleInfo.split(CSV_SPLIT);
         for (int i = 0; i < titles.length; i++) {
             String titleName = titles[i];
             if (titleName.equals("ID")) {
                 idIndex = i;
                 continue;
             }
             if (titleName.equals("NAME")) {
                 nameIndex = i;
                 continue;
             }
             if (titleName.equals("SEX")) {
                 sexIndex = i;
                 continue;
             }
             if (titleName.equals("AGE")) {
                 ageIndex = i;
                 continue;
             }
         }
         if (idIndex == -1
                 || nameIndex == -1
                 || sexIndex == -1
                 || ageIndex == -1) {
             return false;
         }
         return true;
     }

     /**
      * 读取csv文件
      *
      * @return 数据
      */
     private static List<Person> readCsv() {
         File file = new File(fileName);
         if (null == file) {
             return new ArrayList<Person>();
         }
         if (!file.exists()) {
             return new ArrayList<Person>();
         }
         BufferedReader bufferedReader = null;
         List<Person> personList = new ArrayList<Person>(10);
         try {
             bufferedReader = new BufferedReader(new FileReader(file));
             if (!checkTitle(bufferedReader.readLine())) {
                 return new ArrayList<Person>();
             }
             String line = "";
             while (null != (line = bufferedReader.readLine())) {
                 String[] personInfo = line.split(CSV_SPLIT);
                 Person person = new Person();
                 person.setId(personInfo[idIndex]);
                 person.setName(personInfo[nameIndex]);
                 person.setSex(personInfo[sexIndex]);
                 person.setAge(Integer.parseInt(personInfo[ageIndex]));
                 personList.add(person);
             }
         }
         catch (IOException e) {
             e.printStackTrace();
         }
         finally {
             try {
                 bufferedReader.close();
             }
             catch (IOException e) {
                 e.printStackTrace();
             }
         }
         return personList;
     }

     public static void main(String[] args) {
         writeCsv();
         List<Person> personList = readCsv();
         for (int i = 0; i < personList.size(); i++) {
             Person person = personList.get(i);
             System.out.println("id=" + person.getId()
                     + ",name=" + person.getName()
                     + ",sex=" + person.getSex()
                     + ",age=" + String.valueOf(person.getAge()));
         }
     }
 }

结果验证：
写文件


读文件

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