cn.hutool.core.collection.LineIter Maven / Gradle / Ivy
package cn.hutool.core.collection;
import cn.hutool.core.io.IORuntimeException;
import cn.hutool.core.io.IoUtil;
import cn.hutool.core.lang.Assert;
import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.io.Serializable;
import java.nio.charset.Charset;
/**
* 将Reader包装为一个按照行读取的Iterator
* 此对象遍历结束后，应关闭之，推荐使用方式:
*
*
* LineIterator it = null;
* try {
* it = new LineIterator(reader);
* while (it.hasNext()) {
* String line = it.nextLine();
* // do something with line
* }
* } finally {
* it.close();
* }
*
*
* 此类来自于Apache Commons io
*
* @author looly
* @since 4.1.1
*/
public class LineIter extends ComputeIter implements IterableIter, Closeable, Serializable {
private static final long serialVersionUID = 1L;
private final BufferedReader bufferedReader;
/**
* 构造
*
* @param in {@link InputStream}
* @param charset 编码
* @throws IllegalArgumentException reader为null抛出此异常
*/
public LineIter(InputStream in, Charset charset) throws IllegalArgumentException {
this(IoUtil.getReader(in, charset));
}
/**
* 构造
*
* @param reader {@link Reader}对象，不能为null
* @throws IllegalArgumentException reader为null抛出此异常
*/
public LineIter(Reader reader) throws IllegalArgumentException {
Assert.notNull(reader, "Reader must not be null");
this.bufferedReader = IoUtil.getReader(reader);
}
// -----------------------------------------------------------------------
@Override
protected String computeNext() {
try {
while (true) {
String line = bufferedReader.readLine();
if (line == null) {
return null;
} else if (isValidLine(line)) {
return line;
}
// 无效行，则跳过进入下一行
}
} catch (IOException ioe) {
close();
throw new IORuntimeException(ioe);
}
}
/**
* 关闭Reader
*/
@Override
public void close() {
super.finish();
IoUtil.close(bufferedReader);
}
/**
* 重写此方法来判断是否每一行都被返回，默认全部为true
*
* @param line 需要验证的行
* @return 是否通过验证
*/
protected boolean isValidLine(String line) {
return true;
}
}