输入输出类

import java.io.*;

public class KeyboardInput{

private final BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
public final synchronized int readInteger(){
String input="";
int value=0;
try{
input=in.readLine();
}
catch (IOException e){}
if(input!=null){
try{
value=Integer.parseInt(input);
}
catch(NumberFormatException e){}
}
return value;
}

public final synchronized long readLong(){
String input="";
long value=0L;
try{
input=in.readLine();
}
catch (IOException e){}
if(input!=null){
try{
value=Long.parseLong(input);
}
catch(NumberFormatException e){}
}
return value;
}

public final synchronized double readDouble(){
String input="";
double value=0.0D;
try{
input=in.readLine();
}
catch (IOException e){}
if(input!=null){
try{
value=Double.parseDouble(input);
}
catch(NumberFormatException e){}
}
return value;
}

public final synchronized float readFloat(){
String input="";
float value=0.0F;
try{
input=in.readLine();
}
catch (IOException e){}
if(input!=null){
try{
value=Float.parseFloat(input);
}
catch(NumberFormatException e){}
}
return value;
}

public final synchronized char readCharacter(){
char c=;
try{
c=(char)in.read();
}
catch (IOException e){}
return c;
}

public final synchronized String readString(){
String s="";
try{
s=in.readLine();
}
catch (IOException e){}
if(s==null){
s="";
}
return s;
}
}

来源：https://www.cnblogs.com/wjun530/archive/2007/10/06/915115.html