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
";
            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("
");
            }
        }
        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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