http断点续传简单实现（java)

/* > \3ah4"o  
**SiteFileFetch.java |3;(~a)%  
*/ Vclr2]eV4O  
package NetFox; EMlIxpCn:  
import java.io.*; %cX"#+e  
import java.net.*; >,"sHm}l%  
,=|4:F9
  
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public class SiteFileFetch extends Thread { ne4c%?>t  
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< Dd%  
SiteInfoBean siteInfoBean = null; //文件信息Bean QU/fT_ORw  
long[] nStartPos; //开始位置 E-fr}R}  
long[] nEndPos; //结束位置 QHzgy?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z(me@P!D~  
long nFileLength; //文件长度 >)Gd:636+  
boolean bFirst = true; //是否第一次取文件 Mra35  
boolean bStop = false; //停止标志 F;u_7OM  
File tmpFile; //文件下载的临时信息 x=]S.XI  
DataOutputStream output; //输出到文件的输出流 l~J*' m2  
IU#x[P!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5ZK&fKeCF  
public SiteFileFetch(SiteInfoBean bean) throws IOException d~@q%-`lA  
{ Zu21L3  
siteInfoBean = bean; s+
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); m'x;,xfY&F  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); b,@aqu  
if(tmpFile.exists ()) %d;<2
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{ tnb$sulc+  
bFirst = false; VFj(M j`}G  
read_nPos(); *Qkc[XHqy  
} =eBmBn  
else 3b!,D  
{ gnLn7?  
nStartPos = new long[bean.getNSplitter()]; >A}0Ho  
nEndPos = new long[bean.getNSplitter()]; SEM8`lnu  
} C\Vg{&'  
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} nt ,7u(  
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public void run() >72JV;W]  
{ 30Drrno7Io  
//获得文件长度 r:&|vP  
//分割文件 xAhxD|4_  
//实例FileSplitterFetch pQWHG#?7  
//启动FileSplitterFetch线程 #NNewzC<*  
//等待子线程返回 CQ^3v09N;~  
try{ ^jD1vUL 2:  
if(bFirst) v`DI<Lt  
{ \
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nFileLength = getFileSize(); 3`F) AWzdr  
if(nFileLength == -1) =Z,5$6%)  
{ =X(%Svnp  
System.err.println("File Length is not known!"); H&4~Uo.5  
} Rc[0aj:  
else if(nFileLength == -2) zY=jXa)K~  
{ A\QJLWBv^$  
System.err.println("File is not access!"); 7:Ztuc]  
} '6-$Xq0^E  
else o3N]`xD'  
{ \we\0@v  
for(int i=0;i<nStartPos.length;i++) 6f)2F< 7  
{  HpW 42  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); SVWIEH0?  
} #sB,1"  
for(int i=0;i<nEndPos.length-1;i++) 9&Ne+MY^%  
{ d]wD[]  
nEndPos = nStartPos[i+1]; g(hOg~S\E  
} '#\1uXM1U?  
nEndPos[nEndPos.length-1] = nFileLength; @
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} E D"!n-Hq  
} "Fnq>iR-  
A??@AP[7M  
}#`:Qb \U  
//启动子线程 @f1*eo5f  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; cYNV\b4-  
for(int i=0;i<nStartPos.length;i++)
lr@#^  
{ NwlU%{7W6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -YGbfd<wq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), T:iP="?{  
nStartPos,nEndPos,i); _.V?A*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Sq2P-y!w  
fileSplitterFetch.start(); NHQF^2\\  
} M+P$/Wk  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jO~:<y3 =  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X~9j$3lUBR  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =L
-I-e97@  
nEndPos = " + nFileLength); F<&!b2)ML  
// fileSplitterFetch[nPos.length-1].start(); LnsD  
Ao9R:|9  
DcD{*t?x  
//等待子线程结束 %O[N}_XHEh  
//int count = 0; JXqr3Np1  
//是否结束while循环 l$xxrb9P!  
boolean breakWhile = false; GqKsK r2%  
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B 0ee?VC  
while(!bStop) Wp0 Dq(  
{ }8K4-[\  
write_nPos(); YT#3n  
Utility.sleep(500); ]lOh&Cz[  
breakWhile = true; s5&@Cxzl  
`~BZ1)@  
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for(int i=0;i<nStartPos.length;i++) ~x:DXEV,  
{ w.{&=WTr  
if(!fileSplitterFetch.bDownOver) v-b0\_  
{ lUOvm\  
breakWhile = false; Qdk6Qubi!  
break; v`PY>c6~  
} *Zk>2<^R  
} L1{GL #qV  
if(breakWhile) 5z}w}zdg  
break; 23F/\2MSG  
u.XQ&  
p=Q0!!_r  
//count++; TUK"nKSZ`.  
//if(count>4) ,:2'YB  
// siteStop(); Z8O n%Mx{"  
} c}Z6V1]QP  
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System.err.println("文件下载结束！"); k?B[>aQn.0  
} )!bUR\  
catch(Exception e){e.printStackTrace ();} Uz7oL8  
} %r\n%$@_  
2
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//获得文件长度 "r4AY  
public long getFileSize() D/ybFk  
{ [lzN !!B!  
int nFileLength = -1; op2Of<{h  
try{ H`hnEOyLp  
URL url = new URL(siteInfoBean.getSSiteURL()); x
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _gj&$zP  
httpConnection.setRequestProperty("User-Agent","NetFox"); \>. LW9  
1/+C5Bp*  
}|OaL*|u  
int responseCode=httpConnection.getResponseCode(); >SF Uy\3  
if(responseCode>=400) 1$/MrPT(b  
{ &F *'B|n  
processErrorCode(responseCode); 82{&# Vc  
return -2; //-2 represent access is error 5|0,X<
&  
} Q#I"_G&{  
C*=Xk/0  

_9 .(a
  
String sHeader;
fEf_F r  
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!LMN[3M_  
for(int i=1;;i++) +j_;(Gw7  
{ |y;}zQB-dH  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )> ,wj  
//Utility.log(in.readLine()); d_UN
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sHeader=httpConnection.getHeaderFieldKey(i); B(a-
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if(sHeader!=null) ia&AW  
{ (_kp{0r#  
if(sHeader.equals("Content-Length")) e~%  ;K4  
{ Pt:e!qX)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M-L2w"  
break; -H^oXeN  
} mYN7kYR}<`  
} r`y ezbG  
else - O98pi  
break; >2$5eI  
} v,-{Z1N%m  
} G'2#9<c*  
catch(IOException e){e.printStackTrace ();} O4\Z!R60g  
catch(Exception e){e.printStackTrace ();} U@ ?LP  
;h6v@)#GX  
_ n
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Utility.log(nFileLength); k(>h^  
@bM2{Rh:  
&X@Bs-  
return nFileLength; sIG7S"k>p  
} <U5wB]]  
b5$JfjI  
]xC#rwHUC  
//保存下载信息（文件指针位置） Ac2(O6  
private void write_nPos() q5h*`7f  
{ cMyiW$;  
try{ Q$& sTM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); fH`P[^N  
output.writeInt(nStartPos.length); fx=Awba  
for(int i=0;i<nStartPos.length;i++) ,g-EW jN  
{ rk+#GO{  
// output.writeLong(nPos); ~7~~S*EQ  
output.writeLong(fileSplitterFetch.nStartPos); ](tx<3h  
output.writeLong(fileSplitterFetch.nEndPos); {2/LRPT  
} <DKS
+R  
output.close(); m }a|FS  
} Y$N)^=7  
catch(IOException e){e.printStackTrace ();} ^4r73ak/):  
catch(Exception e){e.printStackTrace ();} B]m@:|Q  
} 4c oJRqf=  
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//读取保存的下载信息（文件指针位置） 3G.5724,  
private void read_nPos() Qy<[7  
{ gmIqT f  
try{ EXP%Mk/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U4m9e|/H;z  
int nCount = input.readInt(); /{wJEuE  
nStartPos = new long[nCount]; )1N 54FNO  
nEndPos = new long[nCount]; ul%h@=n  
for(int i=0;i<nStartPos.length;i++) ZX ?yL>4  
{ D3|oOOoG  
nStartPos = input.readLong(); TG}*5Z`  
nEndPos = input.readLong(); 0TfS=scT  
}  tz#gClo  
input.close(); 4h@Z/G!T3
 
} /9o!
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catch(IOException e){e.printStackTrace ();} JnHo9K2.  
catch(Exception e){e.printStackTrace ();} !d<"nx[2`  
} k(zsm"<q  
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O: @}lK+H  
private void processErrorCode(int nErrorCode) NCxqh<  
{ RoCfJ65  
System.err.println("Error Code : " + nErrorCode); 0|R#Tb;Y  
} iXyO(w4D  
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uOa26kE4  
//停止文件下载 J]m{b09F  
public void siteStop() #cj6{%c4  
{ uB!kM  
bStop = true; .(pN5JI*  
for(int i=0;i<nStartPos.length;i++) 763+uFx^  
fileSplitterFetch.splitterStop(); ;'81jbh  
t){"Tfc:  
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} {Fzs@,|W.  
} )c l5B{1P  
//负责部分文件的抓取 \~LQ%OM  
**FileSplitterFetch.java "NgoaG~!YO  
*/ m*$|GW9  
package NetFox; Vd=yr'?  
*3T|
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_+ .\@{c  
import java.io.*; `"qP  
import java.net.*; <hwy*uBrD  
^$&k5e/}C  
_EF&A-kX|u  
public class FileSplitterFetch extends Thread { tzy'G"P|  
)K'N(w  
9;?UvOI;  
String sURL; //File URL }K8/-d6  
long nStartPos; //File Snippet Start Position $T :un.TM  
long nEndPos; //File Snippet End Position )5|I_PXB  
int nThreadID; //Thread's ID rQ=,y>-*  
boolean bDownOver = false; //Downing is over 'ejvH;V3i  
boolean bStop = false; //Stop identical lV.F,3  
FileAccessI fileAccessI = null; //File Access interface E~LTb) !  
&Q}*+Y]G  
iS5W>1]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException LN_xq&.  
{ _z[#}d;k  
this.sURL = sURL; tK k#LWB  
this.nStartPos = nStart; tDr#H!2 3  
this.nEndPos = nEnd; ;Jd3u -  
nThreadID = id; BL 3gKx.'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 TNQP"9[?  
} <(vCiH9~P  
U35AX9/  
2>*%q%81  
public void run() vSonkJ_  
{ N41R  
while(nStartPos < nEndPos && !bStop) OLI$1d_  
{ ,RN:^5 p  
KRjV}\}  
w,Ee>cV]a  
try{ z"*/mP2  
URL url = new URL(sURL); =V"(AuCVE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
b=3H  
httpConnection.setRequestProperty("User-Agent","NetFox"); &CwFdx:Ff  
String sProperty = "bytes="+nStartPos+"-"; D/h/Y) Y  
httpConnection.setRequestProperty("RANGE",sProperty); u !!X6<  
Utility.log(sProperty); s|y:UgD  
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InputStream input = httpConnection.getInputStream(); MQKfJru7  
//logResponseHead(httpConnection); 4Z|vnj)Z  
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byte[] b = new byte[1024]; l|5fE1K9U  
int nRead; hR5_+cuIp  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) w\}?(uO  
{ US  
nStartPos += fileAccessI.write(b,0,nRead); !;_H$r0
  
//if(nThreadID == 1) ITy/eZ"&:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  JMdPwI  
} \ u_ui  
e$Y[Z{T5  
pKS {6P  
Utility.log("Thread " + nThreadID + " is over!"); Su 5>$  
bDownOver = true; 16SOIT  
//nPos = fileAccessI.write (b,0,nRead); rxme(9M  
} Lr`
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catch(Exception e){e.printStackTrace ();} }h 3K@R   
} L,;D@Xi  
} OIl#DV.  
q$G,KRy/  
n4lutnF  
//打印回应的头信息 nL:SG{7  
public void logResponseHead(HttpURLConnection con) h$N0D !  
{ >%E([:$A  
for(int i=1;;i++) ~:km]?lz0  
{ 8.bKb<y  
String header=con.getHeaderFieldKey(i); 5PcJZi^.l
 
if(header!=null) 8P: Rg%0)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); G|8%qd  
Utility.log(header+" : "+con.getHeaderField(header)); |w}xl'>q  
else {YUIMd!Y  
break;  Xtq{%  
} a^5^gId5l!  
} fIF<g@s  
VOsqJJ3  
zY+Fl~$S  
public void splitterStop() lt$zA%`odc  
{ HyiFy7j  
bStop = true; Hqh6:
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} VDB;%U*D  
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Nx#4W1B[`H  
} S]sk7  
v&FF|)$  
D}3XFuZs_  
/* xyr+_k-x&q  
**FileAccess.java k#bu#YZk  
*//文件访问(定位，写) J
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package NetFox; c.\O/N   
import java.io.*; 9t@:4O  
YGc^h(d  
avp;*G}  
public class FileAccessI implements Serializable{ (SVWdgb  
-oz`"&%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^BZkHAp  
RandomAccessFile oSavedFile; bU 63X={  
long nPos; C}Ibx
Kl  
n3MWs);5  
ZWV|# c<G  
public FileAccessI() throws IOException mYB`)M*Y  
{ :"0J=>PH:  
this("",0); b{DiM098  
} PCc|}*b  
=G~~?>=@2  
!A8^Xmz"  
public FileAccessI(String sName,long nPos) throws IOException -G &_^"=R  
{ #0b&^QL  
oSavedFile = new RandomAccessFile(sName,"rw"); 3>z[
PPw  
this.nPos = nPos; ;evCW$G=  
oSavedFile.seek(nPos); k&hc m  
} o-7>eE}+  
H]<]^Zmjy  
f]~c)P Cs  
public synchronized int write(byte[] b,int nStart,int nLen) 2}}?'PwwT  
{ T)7TyE|"2g  
int n = -1; P];JKE%  
try{ V[pv
J(  
oSavedFile.write(b,nStart,nLen); [AEBF2OIv  
n = nLen; +?RGta'%k  
} J3S&3+2G  
catch(IOException e) `29TY&p+"  
{ 4aZCFdc  
e.printStackTrace (); ,$r2gr!_G  
} 
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kR.wOJ7'  
 Kn+=lCk  
return n; ST1Ts5I  
} 'Tb0-1S?  
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}F`beoMAkM  
} dGH_ z8  
o6j"OZcv  
%|3e.1oX  
/* VlW9UF-W  
**SiteInfoBean.java #G_/.h@  
*/ i%(yk#=V  
package NetFox; m^!Sv?hV  
t\5c@j p  
YaFcz$GE_  
public class SiteInfoBean { AvRcS]@=  
_^uc 0=  
<4F7@q,V  
private String sSiteURL; //Site's URL Y4~vC[$x'  
private String sFilePath; //Saved File's Path 'ND36jHcRD  
private String sFileName; //Saved File's Name q G;-o)h  
private int nSplitter; //Count of Splited Downloading File Md(JIlh3  
O4+F^+qN  
e&J3N  
public SiteInfoBean() 
I{n;4?  
{//nSplitter的缺省值为5 O
.:I,D&]  
//default value of nSplitter is 5 5}<[[}(  
this("","","",5); [%.18FWI  
} kJ8vKcc  
]xq::a{Oy  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {vfq  
{ 2,AaP*,  
sSiteURL= sURL; ]t/f<jKN^  
sFilePath = sPath; *C_[jk@6  
sFileName = sName; &tBA^igXK  
this.nSplitter = nSpiltter; )1_(>|@oi  
%_tk7x  
xURw,  
} Xu]h
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V<-htV  
public String getSSiteURL() rb
h[j@s@  
{ zUQe0Gc.b^  
return sSiteURL; ]C)|+`XE@  
} t-lv|%+8
 
:Y.e[@!1x  
~PYFYjHC  
public void setSSiteURL(String value) F"BL#g66  
{ :`zV [A:D  
sSiteURL = value; nO_!:6o".  
} }N|\   
5Bd(>'ig_  
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public String getSFilePath() VCf|`V~G  
{ J9a $AU*  
return sFilePath; {5 Kz'FT  
} Qtnv#9%Vi  
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;.0LRWcJ  
public void setSFilePath(String value) `e*61k5  
{ bFn(w:1Q  
sFilePath = value; PSEWL6=]N  
} ?360SQ<  
E!dp~RwZu  
QRagz,c  
public String getSFileName() 96)v#B?p  
{ >t,
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return sFileName; /#IH-2N  
} 1)Eq&ASB  
{r{>?)O  
|`v^d|  
public void setSFileName(String value) 0x4l5x$8  
{ ~ a>S#S  
sFileName = value; dgY5ccP  
} ecT]p  
s[Gswd  
<)J55++  
public int getNSplitter() Re\o v x9  
{ }6@%((9E2  
return nSplitter; W+
/2c4$F3  
} h.D^1  
r"[L0Cbb  
fU`T\  
public void setNSplitter(int nCount) /'"R Mq  
{ pLJeajv)z  
nSplitter = nCount; |DGCdB|`G  
} :W%4*-FP  
} 7H?!RYrx  
_0*=u$~R  
,L~snR'w  
/* >E~~7Yal  
**Utility.java g6`.qyVfz'  
*/ bx]14}6  
package NetFox; \aB&{`iG  
G "c/a8  
R{ 4u|A?9  
public class Utility { T#/11M$uQ  
4zwif&  
5Ny0b|+p  
public Utility() 6<+8}`@B>G  
{
X;5S  
vS2(Q0+TZi  
rSbQ}O4V  
} >["Kd.ye  
"|\94  
//线程睡眠 3} l;  
public static void sleep(int nSecond) z(r"JNO@  
{ ]svw CPu C  
try{ zM)M_L  
Thread.sleep(nSecond); I>!|3ElT  
} 78gob&p?  
catch(Exception e) 6eOxF8  
{ s?HsUD$b  
e.printStackTrace (); |})rt5|f1!  
} %"{?[!C ?  
} KM EXT$p  
zcZ^s v>  
//日志 ]KzJ u`O%G  
public static void log(String sMsg) n/Or~@pHD  
{ A03I-^0g+  
System.err.println(sMsg); +I?Qg  
} x={kjym L  
=:kiSrBS3t  
eNH
pgj  
public static void log(int sMsg) Y{`3`Pg&N  
{ x!Y(Y=i>  
System.err.println(sMsg); 9j9YQ2  
} $]xE$dzJ  
} 6_x}.bkIx=  
e_tZja2s  
lrq>TJEcx  
/* <d3PDO@w/  
**TestMethod.java USH@:c#t  
*/ A3m{jbh  
package NetFox; N;e}dwh&  
"K/[[wX
\b  
`"i^'VL,  
public class TestMethod { pW`ntE#L  
hqdC9?\  
+qE,<c
}}  
public TestMethod() v#{G8'+%  
{ ///xx/weblogic60b2_win.exe yIn/Y0No  
try{ mYzsTUq  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  zjZ;xn  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); m4wPuW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); U&tfl/  
fileFetch.start(); q}wl_ku9+  
} {ILp[&sL  
catch(Exception e){e.printStackTrace ();} 3RBpbTNWp  
ay!6T`U`  
*C[4 (DmB  
} ahK?]:&QO  
WRN8#b  
Nv}U/$$S  
public static void main(String[] args) F5:2TEA  
{ P2A]qX  
new TestMethod(); (CKhY~,/u  
} tuL\7 (R  
} FN{H\W1cf  
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