对文本的排序
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet;
public class Test {
public static void main(String[] args) {
Test t = new Test();
System.out.println(t.getData("a.txt"));
t.writeFile(t.getData("a.txt"), "b.txt");
}
public Set<Student> getData(String filename) {
Set<Student> datas = new TreeSet<Student>();
// FileReader r = null;
BufferedReader bf = null;
try {
bf = new BufferedReader(new FileReader(new File(filename)), 10240);
String info = null;
while ((info = bf.readLine()) != null) {
String[] tem = info.split(",");
Student s = new Student(tem[0], tem[1], Integer.parseInt(tem[2]));
datas.add(s);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
bf.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return datas;
}
public boolean writeFile(Set< Student> datas,String filename){
if(datas == null || datas.size()<=0)
return false;
if(filename == null||filename.length()<=0)
return false;
BufferedWriter w = null;
try {
w = new BufferedWriter(new FileWriter(new File(filename),true));
Iterator< Student> it = datas.iterator();
while(it.hasNext()){
Student s = it.next();
String tmp = s.getId()+","+s.getName()+","+s.getAge()+"/n";
w.write(tmp);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
try {
w.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return true;
}
}
class Student implements Comparable<Student> {
private String id;
private String name;
private int age;
public int compareTo(Student o) {
// TODO Auto-generated method stub
if (id.compareTo(o.getId()) > 0) {
return 1;
} else if (id.compareTo(o.getId()) < 0) {
return -1;
} else {
return 0;
}
}
public Student(String id, String name, int age) {
this.id = id;
this.age = age;
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String toString(){
return "id="+id+","+"name="+name+","+"age="+age;
}
}
//方法2
/*
* Created on Sep 26,2008
*
* Copyright by 布谷鸟
*/
package file;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
/**
*
* @Author <a href = "qingshuixiang@live.cn">cuckoo</a>
* @Time 11:20
* @Description 文本文件a.txt 中有以下记录 id，name ,age, 如何用Java实现从a文件读取记录，并按id 排序后输出到文本文件b.txt中
*/
public class SortFile {
public static void main(String args[]){
SortFile sortFile = new SortFile();
String orginalPath = "c:/file.txt" ;
List<Entity> list = sortFile.readFile(orginalPath);
String newPath = "c:/result.txt" ;
sortFile.writeFile(list,newPath);
}
/**
* @Description 读取文件，并排序
* @return
*/
public List<Entity> readFile(String path){
File file = new File(path);
List<Entity> list = new ArrayList<Entity>();
try {
System.out.println("-------------开始读文件---------------");
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
String readLine = null ;
while((readLine = reader.readLine()) != null ){
String id = null ;
String name = null ;
String age = null ;
readLine = readLine.trim();
id = readLine.substring(0, readLine.indexOf(" ")).trim();
readLine = readLine.substring(readLine.indexOf(" "),readLine.length()).trim();
name = readLine.substring(0,readLine.indexOf(" ")).trim();
age = readLine.substring(readLine.indexOf(" "),readLine.length()).trim();
Entity entity = new Entity(id,name,age);
list.add(entity);
}
reader.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("----------------读文件结束-------------------");
Comparator comparator = new Comparator(){
public int compare(Object o1, Object o2) {
// TODO Auto-generated method stub
Entity p1 = (Entity) o1;
Entity p2 = (Entity) o2;
if (p1.getId() > p2.getId())
return 1;
else
return 0;
}
};
//排序
Collections.sort(list,comparator);
return list ;
}
/**
* @Description 将排序结果存到另一个文件中
* @param path
*/
public void writeFile(List<Entity> list,String path){
File file = new File(path);
if(file.exists()){
file.delete();
}
//换行
String lineSepeter = System.getProperty("line.separator");
try {
BufferedWriter writer = new BufferedWriter( new OutputStreamWriter(new FileOutputStream(path)));
Iterator<Entity> it = list.iterator();
String content = "" ;
while(it.hasNext()){
Entity entity = it.next();
String readLine = entity.getId()+" "+entity.getName()+" "+entity.getAge()+lineSepeter;
content+=readLine ;
}
writer.write(content);
writer.close();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("写入文件完成");
}
private class Entity{
public Entity(String id ,String name ,String age) {
// TODO Auto-generated constructor stub
try {
_id = Integer.parseInt(id);
_name = name;
_age = Integer.parseInt(age);
}catch (NumberFormatException e){
System.out.println("文件格式不正确");
}
}
public void setId(int id){
_id = id ;
}
public int getId(){
return _id ;
}
public void setName(String name){
_name = name ;
}
public String getName(){
return _name ;
}
public void setAge(int age){
_age = age ;
}
public int getAge(){
return _age ;
}
private int _id = 0 ;
private String _name = null ;
private int _age = 0 ;
}
}
版权声明：本文为博主原创文章，未经博主允许不得转载。
