如何使用Printwriter将字符串数组写入java中的文本文件?
我需要帮助使用Printwriter将数组对象的一些内容(以下是我正在使用的两个数组示例)写入文本文件。有什么想法吗?我是初学者,所以越简单越好,谢谢如何使用Printwriter将字符串数组写入java中的文本文件?,java,arrays,string,file,text,Java,Arrays,String,File,Text,我需要帮助使用Printwriter将数组对象的一些内容(以下是我正在使用的两个数组示例)写入文本文件。有什么想法吗?我是初学者,所以越简单越好,谢谢 Astronauts[0][0] = new Passengers(-1, "", 1, 0, 0, "", "", 0, "", "", "", "", ""); Astronauts[0][1] = new Passengers(0, "Pilot", 2424, 14, 0, "Bruce", "Banner", 0, "678-884
Astronauts[0][0] = new Passengers(-1, "", 1, 0, 0, "", "", 0, "", "", "", "", "");
Astronauts[0][1] = new Passengers(0, "Pilot", 2424, 14, 0, "Bruce", "Banner", 0, "678-884-6325", "Mom", "678-884-6323","","");
Astronauts[0][2] = new Passengers(0, "Pilot", 1248, 3, 0, "Sally", "Forth", 0, "678-921-1135", "Hannah", "678-921-1130","","");
Astronauts[1][0] = new Passengers(-1, "", 2, 0, 0, "", "", 0, "", "", "", "", "");
Astronauts[1][1] = new Passengers(0, "Pilot", 1022, 55, 0, "Buz", "Aldrin", 0, "404-014-4553", "June", "404-014-4555","","");
Astronauts[1][2] = new Passengers(0, "Pilot", 2813, 8, 0, "Alice", "Dyer", 0, "678-884-6325", "Mom", "678-884-6323","","");
我不确定是否正确理解了您的问题,因为将数组的内容写入文件非常简单:
String[] arr = {"a", "b", "c"};
try {
PrintWriter pw = new PrintWriter(new FileWriter("output.txt"));
pw.println(Arrays.toString(arr));
pw.flush();
System.out.println("Finished");
} catch (IOException e) {
e.printStackTrace();
}
[编辑]
我意识到我可能没有解决你的整个问题。如果您想知道如何编写数组中包含的对象的所需特征,可以重写自定义类的方法:
class A {
public static void main(String[] args) {
B[] bs = {new B("a", "b"),
new B("c", "d"),
new B("e", "f"),
new B("g", "h")};
try {
PrintWriter pw = new PrintWriter(new FileWriter("output.txt"));
for (B b : bs) {
pw.println(b);
}
pw.flush();
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("Finished");
}
}
class B {
private String prop1;
private String prop2;
public B (String prop1, String prop2) {
this.prop1 = prop1;
this.prop2 = prop2;
}
@Override
public String toString() {
return this.prop1 + " " + this.prop2;
}
}
PrintWriter
允许使用字符串
,因此您可以重写类中的toString()
方法,然后在一维或二维数组上迭代:
顺便说一下,变量名应该以小写字符开头
- 一维
for (int i = 0; i < astronauts.length; i++) {
pw.print(Arrays.toString(astronauts[i]);
}
for(int i=0;i
- 二维
for (int i = 0; i < astronauts.length; i++) {
for (int j = 0; j < astronauts[i].length; i++) {
pw.print(astronauts[i][j]);
}
}
for(int i=0;i<1.length;i++){
对于(int j=0;j
别忘了flush()
和close()
PrintWriter
以下是您可能想要的方法
String twoDArray[][] = {{"one","two"},{"one","two"},{"one","two"}};
String filePath = "C:/Users/arjun.lajpal/Desktop/dummyFile.txt";
PrintWriter writer = null;
try {
writer = new PrintWriter(filePath);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
writer.printf("%20s%20s","Astraunauts","Passengers");
writer.println();
for(int i=0;i<twoDArray.length;i++){
for(int j=0;j<twoDArray[i].length;j++)
writer.printf("%20s",twoDArray[i][j]);
writer.println();
}
writer.flush();
writer.close();
String twoDArray[]]={{{“一”,“二”},{“一”,“二”},{“一”,“二”},{“一”,“二”};
String filePath=“C:/Users/arjun.lajpal/Desktop/dummyFile.txt”;
PrintWriter=null;
试一试{
writer=新的PrintWriter(文件路径);
}catch(filenotfounde异常){
//TODO自动生成的捕捉块
e、 printStackTrace();
}
writer.printf(“%20s%20s”,“未经审核”,“乘客”);
writer.println();
对于(int i=0;i,因为您的数组内容都属于同一类Passengers
,如果您对默认的array.toString格式不满意,我会在Passengers
中创建一个toString()
方法,返回所需的字符串表示形式
然后:
注意:正如其他人提到的,我将宇航员
变量重命名为小写宇航员
。我还将乘客
类重命名为乘客
编辑:使用上述代码,输出文件应显示在运行程序的工作目录中。或者,您可以提供完整的文件路径,如C:/Users/Me/directory/output.txt
,但在这种情况下,您需要确保目录路径已经存在
另一种选择是修改代码以自动为您创建路径:
File file = new File ("C:/Users/Me/directory/output.txt");
file.getParentFile().mkdirs();
PrintWriter printWriter = new PrintWriter(file);
好的,我使用了这段代码,但对整个文件进行了修改,但仍然没有看到文本文件。是否应该自己弹出一个文件?是的,上面的代码应该为您创建文件。我编辑了答案,并对此进行了一些解释。希望对您有所帮助。
File file = new File ("C:/Users/Me/directory/output.txt");
file.getParentFile().mkdirs();
PrintWriter printWriter = new PrintWriter(file);