write object, read object 不一定比自己parse快速,只是简单,可以扩展好。
如例子,文件“c:/temp/f.txt”是一个5万多行的文本文件。
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.List;
public class ReadObjWriteObj {
private static String orginalFile = "c:/temp/f.txt";
private static String objFile = "c:/temp/obj.txt";
public static void main(String[] args) {
Long start = System.currentTimeMillis();
List<Object> list = (List<Object>) read(orginalFile);
System.out.println(System.currentTimeMillis() - start);
saveObjs(list, objFile);
start = System.currentTimeMillis();
list = readObjs(objFile);
System.out.println(System.currentTimeMillis() - start);
}
public static List<Object> read(String fileName) {
List<Object> list = new ArrayList<Object>();
BufferedReader reader = null;
String line;
try {
reader = new BufferedReader(new InputStreamReader(new FileInputStream(fileName)));
while ((line = reader.readLine()) != null) {
list.add(line);
}
} catch (Exception e) {
} finally {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return list;
}
public static void saveObjs(List<Object> list, String fileName) {
ObjectOutputStream oos = null;
try {
oos = new ObjectOutputStream(new FileOutputStream(fileName));
for(Object o : list) {
oos.writeObject(o);
}
} catch (Exception e) {
} finally {
try {
oos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public static List<Object> readObjs(String fileName) {
List<Object> list = new ArrayList<Object>();
ObjectInputStream ois = null;
try {
ois = new ObjectInputStream(new FileInputStream(fileName));
Object o;
while((o=ois.readObject()) != null) {
list.add(o);
}
} catch (Exception e) {
} finally {
try {
ois.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return list;
}
}
运行结果:
68
756
parse使用的68ms,read对象需要756ms。