1. 读取文件字符流的时候，我们用FileReader，而FileInputStream类用于读字节流。
2.注意，若是函数头部已经声明可能抛出异常，那么一个已经声明可能会抛出异常的函数，调用时得用try-catch处理
3.如果你的函数可能抛出异常，就必须在函数头部加以声明，当然，你也可以声明一种并不会真的抛出的异常（就是说其实这种异常根本不会在这个方法里出现，但仍然可以声明），但注意要在引用的地方catch该异常，并处理
4.BufferedReader与BufferedWriter是什么：
你并不一定要使用这两个类，不用程序也是ok的，但
BufferedReader与BufferedWriter顾名思义就是缓冲读入与缓冲写入，它们的存在是为了提高读入和写入的效率的，当我们想要从文件读入或写入某些数据，如：BufferedReader在读取文件时，会先从文件中读入字符数据并放入缓冲区，而之后若使用read()方法，会先从缓冲区中进行读取，如果缓冲区数据不足，才会再从文件中读取，这样读取的效率会提高，BufferedWriter同理
5.StringTokenizer介绍如下：
StringTokenizer这个类可以实现让我们根据自己需要分割字符串
比如：StringTokenizer D=new StringTokenizer(line,"_");
意思就是对于line这个字符串，我们用_下划线分割，假如line=hello_world_love_you,
经过分割后就变成了4个小字符串hello,world,love,you，对于D，那是一个容器，存放所有分割好的小字符串，用D.nextToken()读取
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;
public class FileCatalogLoader implements CatalogLoader {
private Coffee readCoffee(String line)throws DataFormatException
{
try {
StringTokenizer L=new StringTokenizer(line,"_");
String Coffee=L.nextToken();
String code=L.nextToken();
String description=L.nextToken();
double price=Double.valueOf(L.nextToken());//字符串转成double型数据
String origin=L.nextToken();
String roast=L.nextToken();
String flavor=L.nextToken();
String aroma=L.nextToken();
String acidity=L.nextToken();
String body=L.nextToken();
return new Coffee(code, description, price, origin, roast, flavor, aroma, acidity, body);
} catch (NoSuchElementException e) {
throw e;
}
}
private Product readProduct(String line)throws DataFormatException
{
try {
StringTokenizer B=new StringTokenizer(line,"_");
String product=B.nextToken();
String code=B.nextToken();
String description=B.nextToken();
double price=Double.parseDouble(B.nextToken());
return new Product(code, description, price);
}catch (NoSuchElementException e) {
throw e;
}
}
private CoffeeBrewer readCoffeeBrewer(String line)throws DataFormatException
{
try {
StringTokenizer D=new StringTokenizer(line,"_");
String Brewer=D.nextToken();
String description=D.nextToken();
String code=D.nextToken();
double price=Double.parseDouble(D.nextToken());
String model=D.nextToken();
String waterSupply=D.nextToken();
int numberOfCups=Integer.parseInt(D.nextToken());
return new CoffeeBrewer(description, code, price, model, waterSupply, numberOfCups);
} catch (NoSuchElementException e) {
throw e;
}
}
@Override
public Catalog loadCatalog(String fileName) throws FileNotFoundException, IOException, DataFormatException {
Catalog catalog=new Catalog();
String line;
BufferedReader lbd=new BufferedReader(
new FileReader(fileName)//FileReader用于读取字符流
);
try {
while ((line = lbd.readLine()) != null) {
if (line.startsWith("Coffee")) {
catalog.addProduct(readCoffee(line));
} else if (line.startsWith("Brewer")) {
catalog.addProduct(readCoffeeBrewer(line));
} else if (line.startsWith("Product")) {
catalog.addProduct(readProduct(line));
}
}
}catch (FileNotFoundException e) {
throw e;
}catch (IOException e) {
throw e;
}catch (DataFormatException e) {
throw e;
}
lbd.close();
return catalog;
}
}
还有一个是GourmetCoffee里的writeFile补全代码。
private void writeFile(String filename, String content)
throws IOException {
try {
BufferedWriter lbd=new BufferedWriter(new FileWriter(filename));
lbd.write(content);
lbd.close();
} catch (IOException e) {
throw e;
}
}
