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java json csv文件

錢諍諍1年前9瀏覽0評論

Java是一種流行的編程語言,它被廣泛應用于大型企業級應用程序的開發中。在Java中,處理JSON(JavaScript Object Notation)和CSV(Comma-Separated Values)文件是很常見的需求。示例代碼如下:

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.csv.CsvMapper;
import com.fasterxml.jackson.dataformat.csv.CsvSchema;
public class JsonCsvExample {
public static void main(String[] args) throws JsonProcessingException, IOException {
// 創建一個對象列表
ListpersonList = new ArrayList<>();
personList.add(new Person("張三", 28));
personList.add(new Person("李四", 30));
personList.add(new Person("王五", 32));
// 將對象列表轉換為JSON字符串
ObjectMapper objectMapper = new ObjectMapper();
String jsonContent = objectMapper.writeValueAsString(personList);
System.out.println("JSON字符串:" + jsonContent);
// 將JSON字符串轉換為對象列表
ListpersonListFromJson = objectMapper.readValue(jsonContent, objectMapper.getTypeFactory().constructCollectionType(List.class, Person.class));
System.out.println("對象列表:" + personListFromJson);
// 將對象列表寫入CSV文件
CsvMapper csvMapper = new CsvMapper();
CsvSchema csvSchema = csvMapper.schemaFor(Person.class).withHeader();
FileWriter fileWriter = new FileWriter(new File("persons.csv"));
csvMapper.writer(csvSchema).writeValues(fileWriter).writeAll(personList);
fileWriter.flush();
fileWriter.close();
// 從CSV文件中讀取對象列表
ListpersonListFromCsv = csvMapper.readerFor(Person.class).with(csvSchema).readValues(new File("persons.csv")).readAll();
System.out.println("對象列表:" + personListFromCsv);
}
}
class Person {
private String name;
private int age;
public Person(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
@Override
public String toString() {
return "Person [name=" + name + ", age=" + age + "]";
}
}

上面的代碼演示了如何使用Java將對象列表轉換為JSON字符串,并從JSON字符串中讀取對象列表。還演示了如何將對象列表寫入CSV文件,并從CSV文件中讀取對象列表。