打印阵列

Question

好吧，我试图让文件扫描仪返回数组itemList。 但是，我不明白为什么每次我返回itemList并尝试使用println表单。 它返回：

[Ljava.lang.String;@3d3b5a3a 

[Ljava.lang.String;@10cb42cf 

[Ljava.lang.String;@482d59a3 

[Ljava.lang.String;@18f42160 

当我读它的文件中包含的东西一样

苹果10

鱼20

import java.io.*; 
import java.util.*; 

class loadInventory{ /*This class is used for loading the inventory */ 

private String[] itemList; /*The lines of the inventory are stored in this array */ 
private int numItems;  /* The number of items is stored in this variable */ 

public loadInventory(String fileName){ /*We can do everything in the constructor. It gets the fileName from the superMarket 
               object */ 

itemList = new String[100]; /*We assume there are not more than 100 items in the inventory */ 
numItems=0;     /*initialize numItems to 0*/ 
         /*Read the file using the try-catch block below. We are not specifically catching any exception. 
           We will not cover reading or writing of files and exceptions in this unit. So you 
           don't need to understand this piece of code. */ 
try{ 
    BufferedReader reader = new BufferedReader(new FileReader(fileName)); /*standard code for reading a file */ 
    String line = reader.readLine();  /*read the next line from the file and store in line */ 
    while (line != null){     /*as long as there are lines */ 
      itemList[numItems]= line;   /*store the line in the current location of the array */ 
      numItems++;      /*increment the number of items */ 
      line = reader.readLine();   /*read the next line */ 
     } 

     reader.close();   /*close the reader */ 
    } catch (IOException e){  /*we don't catch any exception */ 
     } 
     System.out.println(itemList); 
    } 

    public String[] getItemList() { 
     return itemList; 

    } 


} 

Answer 1

打印实例的数组是这样的：

System.out.println(Arrays.toString(itemList)); 

Answer 2

int length = itemList.length; 

int count =0; 

while(count<length) 
{ 
System.out.println(itemList[count]); 
count++; 
} 

这是迭代列表最简单的方法。

Answer 3

数组本身使用Object中的默认toString（），因此它不打印其内容。您将需要使用java.util.Arrays.toString（Object []）打印出数组的内容（或者自己循环）。

Answer 4

因为你想打印整个数组对象，而这样做：

System.out.println(itemList); 

相反，你需要打印存储在数组内的一个字符串元素：

System.out.println(Arrays.toString(itemList)); 

Answer 5

不打印直接值为String[]。这样使用，

for (int i = 0; i < itemList.length; i++) { 
System.out.println("Value::> " +itemList[i]); 
} 

Answer 6

多多关注此代码

while (line != null) 
{     
     itemList[numItems]= line;   
     numItems++;      
     line = (String)reader.readLine();   
} 

试试这个。