我有一个主线程，我们从它开始分别执行文件写入和文件读取操作的两个后续线程。我有另一个名为orderDetails的类，它带有属性及其getter和setter。当前程序以这样的方式运行：它将对象列表一直写入文件并将其读回。
问题：我需要将对象（cust1）的内容写入文件并同时从文件中读回。必须对所有对象执行此操作（cust1，cust2）指定。建议解决此问题的可能方法。
主要类
public class MainThread {
public static void main(String[] args) throws InterruptedException {
Thread1 td1=new Thread1();
Thread2 td2=new Thread2();
Thread t1=new Thread(td1);
Thread t2=new Thread(td2);
t1.start();
t1.sleep(100);
t2.start();
}
}
orderDetails类 - 普通的pojo类
public class orderDetails {
private String custName;
private double advancePaid;
private int mobileModel;
private boolean replacement;
private String problemFaced;
private boolean softwareRequirement;
public orderDetails(String custName, double advancePaid, int mobileModel,
boolean replacement, String problemFaced,
boolean softwareRequirement) {
super();
this.custName = custName;
this.advancePaid = advancePaid;
this.mobileModel = mobileModel;
this.replacement = replacement;
this.problemFaced = problemFaced;
this.softwareRequirement = softwareRequirement;
}
public boolean isSoftwareRequirement() {
return softwareRequirement;
}
public void setSoftwareRequirement(boolean softwareRequirement) {
this.softwareRequirement = softwareRequirement;
}
public int getMobileModel() {
return mobileModel;
}
public void setMobileModel(int mobileModel) {
this.mobileModel = mobileModel;
}
public String getProblemFaced() {
return problemFaced;
}
public void setProblemFaced(String problemFaced) {
this.problemFaced = problemFaced;
}
public boolean isReplacement() {
return replacement;
}
public void setReplacement(boolean replacement) {
this.replacement = replacement;
}
public double getAdvancePaid() {
return advancePaid;
}
public void setAdvancePaid(double advancePaid) {
this.advancePaid = advancePaid;
}
public String getCustName() {
return custName;
}
public void setCustName(String custName) {
this.custName = custName;
}
}
文件写入 - 将属性写入文件
public class FileWriting implements Runnable {
orderDetails cust1=new orderDetails("vid",2000.00,2543,true,"display",false);
orderDetails cust2=new orderDetails("kesav",8000.00,7845,false,"battery",true);
ArrayList<orderDetails> orderArr=new ArrayList<orderDetails>();
orderDetails obj;
public void run() {
orderArr.add(cust1);
orderArr.add(cust2);
try {
for(orderDetails obj:orderArr)
{
fileOperations(obj);
}
}
catch (IOException e) {
e.printStackTrace();
}
}
public void fileOperations(orderDetails obj) throws IOException{
File f= new File("C:\\Users\\311518\\Desktop\\threadtest2.txt");
Calendar calNow = Calendar.getInstance();
Calendar orderDate;
SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
FileWriter fstream;
if(f.exists()){
//append mode
fstream = new FileWriter(f,true);
}
else
{
// to open a new file
f.createNewFile();
// write mode
fstream = new FileWriter(f,false);
}
BufferedWriter out = new BufferedWriter(fstream);
out.write(obj.getCustName()+" "+obj.getMobileModel()+" "+obj.getProblemFaced()+" "+obj.getAdvancePaid()+" "+obj.isReplacement()+" "+obj.isSoftwareRequirement());
double balanceAmt=obj.getAdvancePaid()-200;
out.write(" "+balanceAmt);
orderDate = (Calendar) calNow.clone();
out.write(" "+formatter.format(orderDate.getTime()));
orderDate.add(Calendar.DAY_OF_YEAR, + 10);
out.write(" "+formatter.format(orderDate.getTime()));
out.newLine();
out.close();
}
}
文件阅读课程 - 从文件中读取属性
public class FileReading implements Runnable{
File f= new File("C:\\Users\\311518\\Desktop\\threadtest2.txt");
public void run() {
try {
readingText();
System.out.println("Thanks for ur order");
} catch (IOException e) {
e.printStackTrace();
}
}
public void readingText() throws IOException{
String [] temp = null;
FileReader fr = new FileReader(f);
BufferedReader br = new BufferedReader(fr);
String s;
System.out.println("--------ORDER DETAILS------");
System.out.println("Name Model Adv Prob Replacement S/w Bal OrderDate Deliverdate ");
while((s = br.readLine()) != null) {
//display ordered details
temp = s.toString().split("\n");
for(int i=0;i<temp.length;i++){
System.out.println(temp[i]);
}
}
}
}
答案 0 :(得分：1)
您可以尝试使用常见的锁定对象，在编写时锁定它并在阅读之前等待写入完成。 例如：
写：
for(orderDetails obj:orderArr)
{
synchronized(FileWriting.class)
{
fileOperations(obj);
}
Thread.yield();
}
读：
synchronized(FileWriting.class) {
readingText();
Thread.yield();
}
也许您还应该在循环中添加读数并让作者在完成写入时发出信号，以便读者可以停止。
答案 1 :(得分：0)
对于wait（）和notify（）的完美案例，我认为。
FileWriting
FileReading
答案 2 :(得分：0)
您可以执行类似下面代码的上述操作。使用wait()和notify()完美使用生产者消费者线程。
<强> FileOperator.java
public class FileOperator {
File file = new File("D:\\Personal\\MyProjects\\File\\file.txt");
BufferedWriter bw;
BufferedReader br;
boolean isWriteComplete = false;
public FileOperator() throws IOException {
if(!file.exists())
file.createNewFile();
bw = new BufferedWriter(new FileWriter(file));
br = new BufferedReader(new FileReader(file));
}
public void writeInFile(String str) throws IOException{
bw.write(str);
bw.newLine();
bw.flush();
}
public String readFromFile() throws IOException{
return br.readLine();
}
}
这是我们的 FileReaderWriterDemo.java
class ThreadReader implements Runnable{
FileOperator fo;
public ThreadReader(FileOperator fo) {
super();
this.fo = fo;
}
@Override
public void run() {
synchronized (fo) {
if(!fo.isWriteComplete){
try {
fo.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("--------ORDER DETAILS------");
try {
System.out.println(fo.readFromFile());
} catch (IOException e) {
e.printStackTrace();
}
fo.notify();
}
}
}
class ThreadWriter implements Runnable{
FileOperator fo;
public ThreadWriter(FileOperator fo) {
super();
this.fo = fo;
}
@Override
public void run() {
synchronized (fo) {
System.out.println("Going to write...");
try {
fo.writeInFile("OrderNo:1 | advancePaid: 2000 | custName: Mr.XXX | mobileModel: Nokia");
} catch (IOException e) {
e.printStackTrace();
}
fo.isWriteComplete = true;
fo.notify();
}
}
}
public class FileReaderWriterDemo {
public static void main(String[] args) {
FileOperator fop = null;
try {
fop = new FileOperator();
} catch (IOException e) {
e.printStackTrace();
}
Thread tr = new Thread(new ThreadWriter(fop));
tr.start();
Thread tw = new Thread(new ThreadReader(fop));
tw.start();
}
}
控制台输出：
要写
--------订购详情------
订单号：1 | advancePaid：2000 | custName：Mr.XXX | mobileModel：诺基亚
答案 3 :(得分：0)
请找到以下代码示例....
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.RandomAccessFile;
class MyBuffer{
transient byte[] bytes = null;
public int bytesTransmitted = 0;
private int bufferedBytes = 0;
public static boolean isWriting = false;
public static boolean readComplete = false;
MyBuffer(File srcFile,File desFile){
try {
if(!desFile.exists()){desFile.createNewFile();}
ReadThread readThrd = new ReadThread (this,new RandomAccessFile(srcFile,"r"),"read");
// ReadThread readThrd = new ReadThread (this,new FileInputStream(srcFile),"read");
// WriteThread writeThrd = new WriteThread (this,new RandomAccessFile(desFile,"rw"),"write");
WriteThread writeThrd = new WriteThread (this,new FileOutputStream(desFile),"write");
} catch (Exception e) {
e.printStackTrace();
}
}
public void clearBytes() {
this.bytes = null;
this.bytesTransmitted+=this.bufferedBytes;
this.bufferedBytes=0;
MyBuffer.isWriting = false;
}
public byte[] getBytes() {
return this.bytes;
}
public void setBytes(byte[] bytes) {
if(bytes!=null){
if(this.bytes!=null){
byte[] tempByte = new byte[this.bytes.length+bytes.length];
System.arraycopy(this.bytes, 0, tempByte, 0, this.bytes.length);
System.arraycopy(bytes, 0, tempByte, this.bytes.length, bytes.length);
this.bytes = tempByte;
}else{
this.bytes = bytes;
}
this.bufferedBytes+=bytes.length;
}
}
}
class ReadStreamThread implements Runnable{
@Override
public void run() {
// TODO Auto-generated method stub
}
}
class ReadThread implements Runnable{
private Thread t;
private RandomAccessFile file=null;
private FileInputStream fis=null;
private MyBuffer buffer;
ReadThread(MyBuffer obj,RandomAccessFile readFile,String threadName) {
// TODO Auto-generated constructor stub
this.t = new Thread(this,threadName);
this.file = readFile;
this.buffer = obj;
this.t.start();
}
ReadThread(MyBuffer obj,FileInputStream readFis,String threadName) {
// TODO Auto-generated constructor stub
this.t = new Thread(this,threadName);
this.fis = readFis;
this.buffer = obj;
this.t.start();
}
@Override
public void run() {
// TODO Auto-generated method stub
try {
while(true){
if(!MyBuffer.isWriting){
byte[] b = new byte[10];
if(file!=null){
if(this.file.length()<=this.buffer.bytesTransmitted){
this.buffer.setBytes(null);
this.buffer.readComplete = true;
break;
}
this.file.read(b);
this.buffer.setBytes(b);
}else if(fis!=null){
if(this.fis.available()<=this.buffer.bytesTransmitted){
this.buffer.setBytes(null);
break;
}
this.fis.read(b);
this.buffer.setBytes(b);
}
}
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
}
class WriteThread implements Runnable{
private Thread t;
private RandomAccessFile file=null;
private FileOutputStream fos=null;
private MyBuffer buffer;
WriteThread(MyBuffer obj,RandomAccessFile writeFile,String threadName) {
// TODO Auto-generated constructor stub
this.t = new Thread(this,threadName);
this.file = writeFile;
this.buffer = obj;
this.t.start();
}
WriteThread(MyBuffer obj,FileOutputStream writeFos,String threadName) {
// TODO Auto-generated constructor stub
this.t = new Thread(this,threadName);
this.fos = writeFos;
this.buffer = obj;
this.t.start();
}
@Override
public void run() {
// TODO Auto-generated method stub
try {
while(true){
if(this.buffer.getBytes()!=null){
MyBuffer.isWriting = true;
if(this.file!=null){
this.file.write(this.buffer.getBytes());
}else if(this.fos!=null){
this.fos.write(this.buffer.getBytes());
}
this.buffer.clearBytes();
}else{
if(MyBuffer.readComplete)
break;
MyBuffer.isWriting = false;
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
public class ReadWriteModifyMain {
public static void main(String[] args) {
new MyBuffer(new File("C:\\Users\\Manoj\\Samples\\Samplers\\src.txt"),new File("C:\\Users\\Manoj\\Samples\\Samplers\\des.txt"));
}
}