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我試圖從文本文件中讀取文本,並且我已經可以使用system.out.print在系統上打印它。但是,如果我從我在文本文件中讀取的文本中設置了JTextArea
的文本,它將顯示「線程中的異常」主「java.lang.NullPointerException」。它實際上在印刷行中運行良好,並且我已經可以閱讀我想要的內容了,但是我無法將此文本放在JTextArea
上。我該怎麼辦?讀取文本文件中一行中的特定字符數並將「讀取字符」設置爲JTextArea
這裏是我的代碼:
package mdiforms;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
public class trylang extends javax.swing.JInternalFrame {
/** Creates new form trylang */
public trylang() {
initComponents();
}
@SuppressWarnings("unchecked")
public static void main(String[] args) throws Exception {
BufferedReader br = null;
String path = "C:/Users/Pasusani/Desktop/tawa.txt";
try {
// change this value
FileInputStream fis = new FileInputStream(path);
br = new BufferedReader(new InputStreamReader(fis, "UTF-8"));
String CurrentLine;
while ((CurrentLine = br.readLine()) != null) {
processLine(CurrentLine);
}
} finally {
if (br != null) br.close();
}
}
public static void processLine(String line) {
// skip header & footer
//if (line.startsWith("127.0.1.1/dev/sda1")) return;
String name = line.substring(0, 1);
String year = line.substring(0, 5);
System.out.print("Name [" + name + "]\t Year [" + year +"]");
String ewan = "Name [" + name + "]\t Year [" + year +"]";
txt_try.setText(ewan);
}
}
哪裏是NPE?哪一行? – sanbhat
這還不夠。發佈SSCCE來說明問題 – StanislavL
線程「main」中的異常java.lang.NullPointerException at mdiforms.trylang.processLine(trylang.java:110) at mdiforms.trylang.main(trylang.java:91) Java結果: 1 –