有用的java代码

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本文介绍了如何在Java中进行基本的数据类型转换，包括String与int之间的转换；演示了如何向Java文件添加文本；提供了获取当前调用方法名的方法；并详细说明了如何在Java中将String类型转换为Date类型及反之，最后还展示了如何将util.Date转换为sql.Date。

1. 把Strings转换成int和把int转换成String

String a = String.valueOf(2); 
//integer to numeric string  int i = Integer.parseInt(a); //numeric 
string to an int String a = String.valueOf(2);   
//integer to numeric 
stringint i = Integer.parseInt(a); 
//numeric string to an int

2. 向Java文件中添加文本

Updated: Thanks Simone for pointing to exception. I have 

changed the code. BufferedWriter ut = null;  try 

{  out = new BufferedWriter(new FileWriter(”

filename”, true));  out.write(”

aString”);  } catch (IOException e) {  // error processing code  } finally 

{  if (out != null) {  out.close();  }  } BufferedWriter ut = null;try {out = new BufferedWriter(new 

FileWriter(”filename”, true));out.write(”aString”);} catch 

(IOException e) {// error processing code} finally {if (out 

!= null) {out.close();}}

1. 把Strings转换成int和把int转换成String

String a = String.valueOf(2); 
//integer to numeric string  
int i = Integer.parseInt(a); //numeric 
string to an int

String a = String.valueOf(2); //integer to numeric string int i = Integer.parseInt(a); //numeric string to an int

2. 向Java文件中添加文本

Updated: Thanks Simone for pointing to exception. I have 

changed the code. 
BufferedWriter ut = null;  
try 

{  
out = new BufferedWriter(new FileWriter(”

filename”, true));  
out.write(”

aString”);  
} catch (IOException e) {  
// error processing code  
} finally 

{  
if (out != null) {  
out.close();  
}  
}

BufferedWriter ut = null; try { out = new BufferedWriter(new FileWriter(”filename”, true)); out.write(”aString”); } catch (IOException e) { // error processing code } finally { if (out != null) { out.close(); } }

3. 获取Java现在正调用的方法名

String methodName =
Thread.currentThread().getStackTrace()[1].getMethodName();

4. 在Java中将String型转换成Date型

java.util.Date = 
java.text.DateFormat.getDateInstance().parse(date String); java.util.Date = java.text.DateFormat.getDateInstance().parse(date 
String);or SimpleDateFormat format = new SimpleDateFormat( "dd.MM.yyyy" 
);  Date date = format.parse( myString ); SimpleDateFormat format = new SimpleDateFormat( "dd.MM.yyyy" );Date date
= format.parse( myString );

6.将Java中的util.Date转换成sql.Date

java.util.Date utilDate = new 
java.util.Date();  java.sql.Date sqlDate = new java.sql.Date
(utilDate.getTime()); java.util.Date utilDate = new java.util.Date();java.sql.Date sqlDate = 
new java.sql.Date(utilDate.getTime());