使用java修改文本文件内容的问题

如现有一文本文件   内容为  

11111
22222
33333
44444

现在需要把   22222   修改为   55555

import java.io.RandomAccessFile;

public class Test1 {
public static final String fileName = "c:/aaa.txt ";

public static void main(String[] args) {
try {
RandomAccessFile rF = new RandomAccessFile(fileName, "rw");
for (int i = 0; i < rF.length(); i++) {
rF.seek(i);
byte b = rF.readByte();
if (b == '2') {
rF.seek(i);
rF.writeByte(b + 3);
}
}
rF.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}

//在文件后面加入一行
String sitename = Struts2Utils.getRequest().getParameter("sitename");
// 在taglib中加入 网站名称的 变量
String filepath = ConfigManager.getConfigProperty("taglibs.tagpath");

RandomAccessFile raf = new RandomAccessFile(filepath, "rw");
long len = raf.length();
String lastLine = "";
if (len != 0L) {
long pos = len - 1;
while (pos > 0) {
pos--;
raf.seek(pos);
if (raf.readByte() == '\n') {
lastLine = raf.readLine();
break;
}
}
}

String ss = ("<c:set var=\"sitename\" value=\"" + sitename + "\"/>");

if (lastLine.startsWith("<c:set var=\"ctx\""))
raf.write(("\n<c:set var=\"sitename\" value=\"" + sitename + "\"/>")
.getBytes());
if (lastLine.startsWith("<c:set var=\"sitename\"")) {
raf.seek(len - lastLine.length());
raf.write(ss.getBytes());
}
raf.close();

评论

3 楼 zt3124 2012-04-14  

ConfigManager，Struts2Utils分别都是那个jar包里面的啊？希望您能不惜赐教

2 楼 hcwj2009 2011-09-16  

import java.io.RandomAccessFile; 

public class Test1 { 
public static final String fileName = "c:/aaa.txt "; 

public static void main(String[] args) { 
try { 
RandomAccessFile rF = new RandomAccessFile(fileName, "rw"); 
for (int i = 0; i < rF.length(); i++) { 
rF.seek(i); 
byte b = rF.readByte(); 
if (b == '2') { 
rF.seek(i); 
rF.writeByte(b + 3); 
} 
} 
rF.close(); 
} catch (Exception e) { 
e.printStackTrace(); 
} 
} 
} 

//在文件后面加入一行 
String sitename = Struts2Utils.getRequest().getParameter("sitename"); 
// 在taglib中加入 网站名称的 变量 
String filepath = ConfigManager.getConfigProperty("taglibs.tagpath"); 

RandomAccessFile raf = new RandomAccessFile(filepath, "rw"); 
long len = raf.length(); 
String lastLine = ""; 
if (len != 0L) { 
long pos = len - 1; 
while (pos > 0) { 
pos--; 
raf.seek(pos); 
if (raf.readByte() == '\n') { 
lastLine = raf.readLine(); 
break; 
} 
} 
} 

String ss = ("<c:set var=\"sitename\" value=\"" + sitename + "\"/>"); 

if (lastLine.startsWith("<c:set var=\"ctx\"")) 
raf.write(("\n<c:set var=\"sitename\" value=\"" + sitename + "\"/>") 
.getBytes()); 
if (lastLine.startsWith("<c:set var=\"sitename\"")) { 
raf.seek(len - lastLine.length()); 
raf.write(ss.getBytes()); 
} 
raf.close();

1 楼 hcwj2009 2011-09-16  

import java.io.RandomAccessFile;

public class Test1 {
public static final String fileName = "c:/aaa.txt ";

public static void main(String[] args) {
try {
RandomAccessFile rF = new RandomAccessFile(fileName, "rw");
for (int i = 0; i < rF.length(); i++) {
rF.seek(i);
byte b = rF.readByte();
if (b == '2') {
rF.seek(i);
rF.writeByte(b + 3);
}
}
rF.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}

//在文件后面加入一行
String sitename = Struts2Utils.getRequest().getParameter("sitename");
// 在taglib中加入 网站名称的 变量
String filepath = ConfigManager.getConfigProperty("taglibs.tagpath");

RandomAccessFile raf = new RandomAccessFile(filepath, "rw");
long len = raf.length();
String lastLine = "";
if (len != 0L) {
long pos = len - 1;
while (pos > 0) {
pos--;
raf.seek(pos);
if (raf.readByte() == '\n') {
lastLine = raf.readLine();
break;
}
}
}

String ss = ("<c:set var=\"sitename\" value=\"" + sitename + "\"/>");

if (lastLine.startsWith("<c:set var=\"ctx\""))
raf.write(("\n<c:set var=\"sitename\" value=\"" + sitename + "\"/>")
.getBytes());
if (lastLine.startsWith("<c:set var=\"sitename\"")) {
raf.seek(len - lastLine.length());
raf.write(ss.getBytes());
}
raf.close();