com.feilong.io.ReaderUtil Maven / Gradle / Ivy
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feilong is a suite of core and expanded libraries that include utility classes, http, excel,cvs, io classes, and much much more.
/*
* Copyright (C) 2008 feilong
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.feilong.io;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.UncheckedIOException;
import com.feilong.lib.io.IOUtils;
import com.feilong.core.Validate;
/**
* {@link java.io.Reader} 工具类.
*
* @author feilong
* @see java.io.BufferedReader
* @see java.io.CharArrayReader
* @see java.io.FilterReader
* @see java.io.InputStreamReader
* @see java.io.PipedReader
* @see java.io.StringReader
* @see java.io.LineNumberReader
* @since 1.0.9
*/
public final class ReaderUtil{
/** Don't let anyone instantiate this class. */
private ReaderUtil(){
//AssertionError不是必须的. 但它可以避免不小心在类的内部调用构造器. 保证该类在任何情况下都不会被实例化.
//see 《Effective Java》 2nd
throw new AssertionError("No " + getClass().getName() + " instances for you!");
}
//---------------------------------------------------------------
/**
* 构造一个 {@link StringReader}.
*
* @param str
* the str
* @return 如果 str
是null,抛出 {@link NullPointerException}
* @since 1.11.5
*/
public static StringReader newStringReader(String str){
Validate.notNull(str, "str can't be null!");
return new StringReader(str);
}
//---------------------------------------------------------------
/**
* 将 {@link java.io.Reader} 转成 {@link java.lang.String}.
*
* @param reader
* the reader
* @return 如果 reader
是null,抛出 {@link NullPointerException}
* @see com.feilong.lib.io.IOUtils#toBufferedReader(Reader)
* @see com.feilong.lib.io.IOUtils#toString(Reader)
* @since 1.10.6 call {@link com.feilong.lib.io.IOUtils#toString(Reader)}
*/
public static String toString(Reader reader){
Validate.notNull(reader, "reader can't be null!");
//---------------------------------------------------------------
try{
return IOUtils.toString(reader);
}catch (IOException e){
throw new UncheckedIOException(e);
}
}
//---------------------------------------------------------------
/**
* 读取 {@link java.io.Reader} 第一行内容.
*
* @param reader
* the reader
* @return 如果 reader
是null,抛出 {@link NullPointerException}
* @see com.feilong.lib.io.IOUtils#toBufferedReader(Reader)
*/
public static String readLine(Reader reader){
Validate.notNull(reader, "reader can't be null!");
try (BufferedReader bufferedReader = IOUtils.toBufferedReader(reader)){
// 读取一个文本行.通过下列字符之一即可认为某行已终止:换行 ('\n')、回车 ('\r') 或回车后直接跟着换行.
return bufferedReader.readLine();
}catch (IOException e){
throw new UncheckedIOException(e);
}
}
}