看过博主文章都知道，博主不太喜欢废话，讲究实用。避开长篇大论，直接上各位老爷最喜欢的实操代码。关键点都在代码注释中！！
一，代码准备
首先准备依赖
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-csv</artifactId>
<version>1.10.0</version>
</dependency>
<dependency>
<groupId>com.opencsv</groupId>
<artifactId>opencsv</artifactId>
<version>5.7.1</version>
</dependency>准备启动类
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Applications {
public static void main(String[] args) {
SpringApplication.run(Applications.class, args);
}
}
准备关键操作csv的util文件
import com.opencsv.CSVWriter;
import com.opencsv.CSVWriterBuilder;
import com.opencsv.ICSVWriter;
import com.opencsv.bean.CsvToBean;
import com.opencsv.bean.CsvToBeanBuilder;
import com.opencsv.bean.StatefulBeanToCsv;
import com.opencsv.bean.StatefulBeanToCsvBuilder;
import java.io.*;
import java.lang.reflect.Method;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
public class CsvUtil {
/**
* 根据指定的类读取csv文件
*
* @param filepath 文件路径
* @param clazz 读取类
* @param startLine 开始行
* @return
* @param <T>
*/
public static <T> List<T> CSVToBean(String filepath, Class<T> clazz, int startLine) throws IOException {
BufferedReader reader = createBufferedReader(filepath);
try {
CsvToBean<T> csvToBean = new CsvToBeanBuilder<T>(reader).withType(clazz) // 映射的目标类型
.withIgnoreLeadingWhiteSpace(true) //忽略 CSV 文件中每行开头的空白字符。
.withSkipLines(startLine) // 从第几行开始读取数据
.withIgnoreEmptyLine(true) // 忽略空行
.build();
List<T> resultObj = csvToBean.parse();
return resultObj;
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
reader.close();
}
}
private static BufferedReader createBufferedReader(String filepath) throws IOException {
FileInputStream fileInputStream = new FileInputStream(filepath);
InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, StandardCharsets.UTF_8);
return new BufferedReader(inputStreamReader);
}
private static BufferedWriter createBufferedWriter(String filepath) throws IOException {
FileOutputStream fileOutputStream = new FileOutputStream(filepath);
OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fileOutputStream, StandardCharsets.UTF_8);
return new BufferedWriter(outputStreamWriter);
}
/**
* 写为csv文件
*
* @param filepath
* @param content
*/
public static void writeToFile(String filepath, Object content) throws IOException {
BufferedWriter bufferedWriter = createBufferedWriter(filepath);
try {
if (content instanceof List) {
writeList(bufferedWriter, (List<Object>) content);
} else {
writeSingle(bufferedWriter, content);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
bufferedWriter.flush();
bufferedWriter.close();
}
}
private static void writeList(BufferedWriter bufferedWriter, List<Object> content) throws IOException {
CSVWriter csvWriter = new CSVWriter(bufferedWriter);
try {
/**
* 方法一：简单输出为一行 或者输出为多行
*/
String[] strings = new String[content.size()];
for (int i = 0; i < content.size(); i++) {
strings[i] = content.get(i).toString();
// 输出到多行
// csvWriter.writeNext(new String[]{strings[i]});
}
// 只会输出到一行
// csvWriter.writeAll(Collections.singleton(strings));
/**
* 方法二： 输出格式按csv的格式
*/
for (Object e : content) {
Method[] methods = e.getClass().getMethods();
List<String> list = new ArrayList<>();
// 遍历所有方法
for (Method method : methods) {
// 如果方法是 getter 方法（以 "get" 或 "is" 开头，并且没有参数）
if (isGetter(method)) {
try {
// 调用 getter 方法获取属性值
String value = String.valueOf(method.invoke(e));
// 加入list
list.add(value);
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
writeForList(csvWriter, list);
list.clear();
}
} finally {
csvWriter.flush();
csvWriter.close();
}
}
private static void writeForList(CSVWriter csvWriter, List<String> list) {
String[] array = list.toArray(new String[0]);
csvWriter.writeNext(array);
}
// 判断方法是否为 getter 方法
private static boolean isGetter(Method method) {
String name = method.getName();
return (name.startsWith("get") || name.startsWith("is"))
&& !name.startsWith("getClass")
&& method.getParameterCount() == 0
&& !void.class.equals(method.getReturnType());
}
private static void writeSingle(BufferedWriter bufferedWriter, Object content) throws Exception {
ICSVWriter writer = new CSVWriterBuilder(bufferedWriter)
.withSeparator(',')
.withQuoteChar('"')
.withEscapeChar('\\')
.withLineEnd("\n")
.build();
StatefulBeanToCsv<Object> beanToCsv = new StatefulBeanToCsvBuilder<Object>(writer)
.build();
// 将对象列表写入 CSV 文件
beanToCsv.write(content);
}
}准备测试用的model类
import com.opencsv.bean.CsvBindByName;
import com.opencsv.bean.CsvBindByPosition;
import lombok.*;
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
public class RojerCSVModel {
/**
* @CsvBindByName注解是根据 CSV 文件中的列名进行绑定
* @CsvBindByPosition根据 CSV 文件中的位置（在哪一列）进行绑定
*/
// @CsvBindByName(column = "Name", required = false)
@CsvBindByPosition(position = 0, required = false)
private String name;
// @CsvBindByName(column = "Age", required = false)
@CsvBindByPosition(position = 1, required = false)
private String age;
// @CsvBindByName(column = "Address", required = false)
@CsvBindByPosition(position = 2, required = false)
private String address;
@Override
public String toString() {
return name +',' + age + ',' + address;
}准备测试用的controller类
import com.luojie.moudle.RojerCSVModel;
import com.luojie.util.CsvUtil;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.ArrayList;
import java.util.List;
@RestController
public class CSVTestController {
@GetMapping("/csv/test")
public void testCsv() throws Exception {
RojerCSVModel csvModel1 = new RojerCSVModel("John", "30", "New York");
RojerCSVModel csvModel2 = new RojerCSVModel("Alice", "25", "London");
RojerCSVModel csvModel3 = new RojerCSVModel("Rojer", "27", "Shang Hai");
List<RojerCSVModel> list = new ArrayList<>();
list.add(csvModel1);
list.add(csvModel2);
list.add(csvModel3);
// 测试写一个的情况
// CsvUtil.writeToFile("D:\\tmp\\test1.csv", csvModel1);
CsvUtil.writeToFile("D:\\tmp\\test1.csv",list);
}
@GetMapping("/csv/test/get")
public void testCsvGet() throws Exception {
List<RojerCSVModel> list = new ArrayList<>();
list = CsvUtil.CSVToBean("D:\\tmp\\test1.csv", RojerCSVModel.class, 0);
System.out.println(list.size());
}
}记得在对应测试路径下准备csv文件
如果不想自己创，可以自己再写个方法去检测如无则创建！
二，代码测试
测试单类写入的情况（调用过程就不展示了）
结果
测试为list时的写入情况
测试读取为list<obj>的情况
希望对各位看官老爷有帮助，如果可以的话，能否请各位老爷点个赞，关注一下博主呢，在这里非常感谢各位老爷了。