http断点续传简单实现（java)

/* <5O:jd  
**SiteFileFetch.java jI/#NCKE  
*/ br;~}GR_h
 
package NetFox; .C|dGE?,  
import java.io.*; yU|=)p5  
import java.net.*; fL(_V/p^  
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l3N '@GO  
public class SiteFileFetch extends Thread { dt5`UBvUg  
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6;  
SiteInfoBean siteInfoBean = null; //文件信息Bean HC!5AJ&+}v  
long[] nStartPos; //开始位置 7<0oK|~c#  
long[] nEndPos; //结束位置 4D)M_O  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b?,''t  
long nFileLength; //文件长度 }Jo}K)>!  
boolean bFirst = true; //是否第一次取文件 fA)4'7UT  
boolean bStop = false; //停止标志 Ex<@:  
File tmpFile; //文件下载的临时信息 yYH>~,  
DataOutputStream output; //输出到文件的输出流 w!r.MWE  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） * `3+x  
public SiteFileFetch(SiteInfoBean bean) throws IOException Owz>g4l r  
{ |
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siteInfoBean = bean; {Q021*xt/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bQ`2ll*(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Z{^P
nit  
if(tmpFile.exists ()) }hA)p:  
{ Lvb'qZ6n  
bFirst = false; h'B0rVQia>  
read_nPos(); Pd+Wb3  
} $C t(M)  
else ra F+Bt`  
{ 3ih:t'N-  
nStartPos = new long[bean.getNSplitter()]; 8;i
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nEndPos = new long[bean.getNSplitter()]; Dc9Fb^]QOG  
} =AP0{  
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} 8Xa{.y"  
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public void run() +{\b&q_  
{ PTpGZ2FZ  
//获得文件长度 PNpH)'C|
 
//分割文件 {#N,&?[  
//实例FileSplitterFetch H<Zs2DP`  
//启动FileSplitterFetch线程 N&G;`  
//等待子线程返回 'XI-x[w  
try{ #]2,1dJ  
if(bFirst) RY}:&vWDk  
{ .*Axr\x3  
nFileLength = getFileSize(); wKE}BO >  
if(nFileLength == -1) W]5sqtF;6  
{ eC='[W<a.  
System.err.println("File Length is not known!"); $-uMWJ)l  
} &4m;9<8\  
else if(nFileLength == -2) MtG~O;?8  
{ rT'<6]`  
System.err.println("File is not access!"); Ubv_a  
} \|7Y"WEQ  
else 3uuB/8  
{ 6'|NALW  
for(int i=0;i<nStartPos.length;i++) K7},X01^  
{ ub-vtRpm  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *#Iqz9X.Y3  
} =c#;c+a  
for(int i=0;i<nEndPos.length-1;i++) ^,#MfF6  
{ "|GX%>/  
nEndPos = nStartPos[i+1]; m88[(l  
} ]m\:XhI*<  
nEndPos[nEndPos.length-1] = nFileLength; S~ZRqL7ZO  
} ?Lem|zo  
} oF.H?lG7`  
$yZ(ws  
Q o
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//启动子线程 KV|ywcGhT  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d[&Ah~,  
for(int i=0;i<nStartPos.length;i++) kOV6O?h  
{ }-PV%MNud  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $ItPUYi";  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^20x\K  
nStartPos,nEndPos,i); #1[Q?e4,0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M(.]?+  
fileSplitterFetch.start(); ?j$*a7[w  
} \l?.VE
D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T2}ccnDi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); u4~(0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", nE"0?VNW$  
nEndPos = " + nFileLength); M7gM#bv>L  
// fileSplitterFetch[nPos.length-1].start(); wb6$R};?  
CW@G(R  
&\Yd)#B/  
//等待子线程结束 8_uh2`+Bvb  
//int count = 0; PF]Vt  
//是否结束while循环 EK}QjY[i  
boolean breakWhile = false; nEh^{6  
baib_-$  
pjNH0mZ  
while(!bStop) o[>p  
{ y:dwx*Q9I  
write_nPos(); 4.'KT;[_1/  
Utility.sleep(500); eo'C)j# U  
breakWhile = true; b*o,re)Dj  
jAO
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hP=z<&zb/  
for(int i=0;i<nStartPos.length;i++) (N$$N:ac[t  
{ G9jlpf5>  
if(!fileSplitterFetch.bDownOver) -0:B2B  
{ hionR)R4  
breakWhile = false; ,E8~^\HV  
break; -1 _7z{.  
} Wg5i#6y8w  
} o/p'eY:)  
if(breakWhile) Lz;E/a}s  
break; -u%'u~s  
P8;f^3V(+/  
;AE%f.Y  
//count++; fa;GM7<e)  
//if(count>4) <>K@#|%Y&  
// siteStop(); -QP&A >]7  
} gfAVxMg  
'gv7&$X}4  
g bwg3$!9  
System.err.println("文件下载结束！"); !Mk:rO-L  
} ,__|SnA.  
catch(Exception e){e.printStackTrace ();} aoS]Qp  
} be5NasC  
# fl%~Y  
h}$]3/5H  
//获得文件长度 4!tHJCq"  
public long getFileSize() m#(ve1E  
{ 8v']>5S]#  
int nFileLength = -1; m7~[f7U  
try{ ^9I^A!w=  
URL url = new URL(siteInfoBean.getSSiteURL()); _\2^s&iJh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5zsXqBG  
httpConnection.setRequestProperty("User-Agent","NetFox"); QtsyMm  
O"x/O#66  
i4oBi]$T  
int responseCode=httpConnection.getResponseCode(); Zc57]~  
if(responseCode>=400) }V %b  
{ \^%5!  
processErrorCode(responseCode); Y/w) V
V  
return -2; //-2 represent access is error 44kb  
} P1mPC  
_G5MQ%z  
8yc?9&/|  
String sHeader; zVs|go>F  
7<VfE`Q3  
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for(int i=1;;i++) wuTCdBu6hU  
{ "RJf2~(ZX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ))>)qav  
//Utility.log(in.readLine()); xj!_]XJ^w  
sHeader=httpConnection.getHeaderFieldKey(i); ^#L?HIM  
if(sHeader!=null) |d1%N'Ll  
{ ?OPAf4h  
if(sHeader.equals("Content-Length")) c~UYs\  
{ _;+N=/l0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $0K%H  
break; 0IEFCDeCO  
} 1f1J'du  
} <U$A_]*w  
else ,/g\;#:{@]  
break; weiqt *,8  
} _"`U.!3*  
} q>q@ztt  
catch(IOException e){e.printStackTrace ();} xbA% 'p  
catch(Exception e){e.printStackTrace ();} o s HE4x  
/Iu._2  
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Utility.log(nFileLength); L%.GKANM  
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y]
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return nFileLength; &xqr&(o  
} 8_tMiIE-pS  
s/K}]F  
~4iIG}Y<  
//保存下载信息（文件指针位置） Th%1eLQ  
private void write_nPos() Tl3{)(ezx  
{ 0R2
AhA#  
try{ /-39od0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); tnmuCz  
output.writeInt(nStartPos.length); ft[g1  
for(int i=0;i<nStartPos.length;i++) ^eEj 5Rh  
{ B"I>mw  
// output.writeLong(nPos); =`X@+~%-  
output.writeLong(fileSplitterFetch.nStartPos); G K @]61b  
output.writeLong(fileSplitterFetch.nEndPos); f.=4p^  
} 'g
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output.close(); )gCHwu  
} [hS?d.D   
catch(IOException e){e.printStackTrace ();} ?Ib/}JST  
catch(Exception e){e.printStackTrace ();} h tn2`  
} t?]6>J_V  
%Ys>PzM  
#?i#q%q  
//读取保存的下载信息（文件指针位置） y=\jQ6Fc  
private void read_nPos() v}]x>f  
{ oA~m*|  
try{ %1]2+_6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <5(8LMF  
int nCount = input.readInt(); .>?["e#,  
nStartPos = new long[nCount]; = sIR[V'(  
nEndPos = new long[nCount]; 9hT^Y,c0  
for(int i=0;i<nStartPos.length;i++) y+?tUSPP  
{ -i'T!Qg1  
nStartPos = input.readLong(); 9kP!O_  
nEndPos = input.readLong(); vmOXB#7W  
} 9VN@M  
input.close(); <E BgHD)  
} +c\s%Gzrh  
catch(IOException e){e.printStackTrace ();} vd /_`l.D  
catch(Exception e){e.printStackTrace ();} KX)xCR~  
} r[Q$w>  
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private void processErrorCode(int nErrorCode) =tH+e7it  
{ &U xN.vl  
System.err.println("Error Code : " + nErrorCode); VSZ6;&2^  
} RQ{w`>K  
S/d})8~.  
S53%*7K.  
//停止文件下载 ["Q8`vV0WO  
public void siteStop() :<&}/r  
{ DcbL$9UI  
bStop = true; Bw*z4qb{yH  
for(int i=0;i<nStartPos.length;i++) vtmO  
fileSplitterFetch.splitterStop(); d!KX.K\NM,  
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} vEzzdDwi6  
} jD^L<  
//负责部分文件的抓取 ,0
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**FileSplitterFetch.java XU9=@y+|v  
*/ ^MJGY,r6b  
package NetFox; hCT%1R}rKr  
|7`Vw Z  
Uzb"$Ue4  
import java.io.*; Z{p6Q1u  
import java.net.*; Sc6wC H  
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public class FileSplitterFetch extends Thread { fe37T@  
"}SERC7  
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String sURL; //File URL y-n\;d>[(  
long nStartPos; //File Snippet Start Position }aNiO85  
long nEndPos; //File Snippet End Position ;@d%<yMf@  
int nThreadID; //Thread's ID XFu@XUk!K  
boolean bDownOver = false; //Downing is over N0vd>b  
boolean bStop = false; //Stop identical ;7`<.y  
FileAccessI fileAccessI = null; //File Access interface g=Qga09  
z{#F9'\&  
f6L_uk`{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zW0AB8l  
{ &vMH AZd  
this.sURL = sURL; INbjk;k  
this.nStartPos = nStart; m]-8?B1`Y  
this.nEndPos = nEnd; ~2H7_+.#  
nThreadID = id; Jl]]nOBQ/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 xD\Km>|i  
} o~-X7)]  
BXfaqYb;Q  
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public void run() uCu,'F,6Y  
{ 3(5RUI-  
while(nStartPos < nEndPos && !bStop) ImV54
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{ Gr6ma*)y~t  
)b%c]!  
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try{ K%pmE?%,8  
URL url = new URL(sURL); "}OFwes
  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q5vs;,_ |  
httpConnection.setRequestProperty("User-Agent","NetFox"); Yip9K[  
String sProperty = "bytes="+nStartPos+"-"; >|Jw,,uf  
httpConnection.setRequestProperty("RANGE",sProperty); jujx3rnK?  
Utility.log(sProperty); D} .t  
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?J~JQe42  
InputStream input = httpConnection.getInputStream(); D@^F6am%  
//logResponseHead(httpConnection); bf74 "  
:T\WYKX3C  
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byte[] b = new byte[1024]; GwW#Ww;Oc  
int nRead; kQ#eWk J,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *c AoE l  
{ `>sqP aD  
nStartPos += fileAccessI.write(b,0,nRead); DYWC]*  
//if(nThreadID == 1) N6J$z\ P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]JD$f
S=_  
} R&4E7wrdP  
uf;q/Wr  
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Utility.log("Thread " + nThreadID + " is over!"); m_(hCY=Q$  
bDownOver = true; q~^:S~q  
//nPos = fileAccessI.write (b,0,nRead); yX-xVvlv@  
} s
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catch(Exception e){e.printStackTrace ();} \9}5}X_x.  
} @qC:% |>  
} |?| u-y  
s{k\1P(G}  
20moX7L  
//打印回应的头信息 xF/DYXC{8  
public void logResponseHead(HttpURLConnection con) .HQ<6k:  
{ 'QS"4EvdD  
for(int i=1;;i++) ltrSTH,kL  
{ eurudl  
String header=con.getHeaderFieldKey(i); kW!:bh  
if(header!=null) /J+)P<_A  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $0
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Utility.log(header+" : "+con.getHeaderField(header)); MzG ryM-  
else &!a2%%1#N  
break; f oVD+\~Y  
} m4DH90~a8  
} 5HbTgNI  
Eo Urc9G2  
v$i%>tQ\  
public void splitterStop() # 0!IUSa  
{ "B}08C,?  
bStop = true; O0{  
} 0l6iv[qu5w  
/K!,^Xn
 
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} =|!~0O  
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/* ;iORfUjxrq  
**FileAccess.java K D-_~uIF  
*//文件访问(定位，写) -(uBTO s  
package NetFox; BLH=:zb5  
import java.io.*; :'dc=C  
1QJ$yr  
N 9&@,3  
public class FileAccessI implements Serializable{ Gx!RaZ1  
NACY;XQ%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 5dp#\J@  
RandomAccessFile oSavedFile; "J5Pwvs-  
long nPos; GF!{SO4  
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public FileAccessI() throws IOException h<K;VpL6  
{ tKeO+6l  
this("",0); m[{&xF|_  
} w)eQ'6Vu  
x#0@$  
$M`;."
 
public FileAccessI(String sName,long nPos) throws IOException IJc#)J.2A  
{ _~nex,;r  
oSavedFile = new RandomAccessFile(sName,"rw"); R{o*O_qX  
this.nPos = nPos; #@6L|$iX  
oSavedFile.seek(nPos); JX)z<Dz$  
} /V<`L  
tMZ(s  
$l;t
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public synchronized int write(byte[] b,int nStart,int nLen) DiQkT R  
{  GQ0(&I  
int n = -1; W79A4l<  
try{ c'+r[rSn1  
oSavedFile.write(b,nStart,nLen); ;]M67ma7C  
n = nLen; 'D"K`Vw  
} gqD^Bs'VF  
catch(IOException e) 9BD|uU;0  
{ I!7.fuO  
e.printStackTrace (); W:poUG1UR  
} K2rS[Kdfaq  
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return n; 6+;2B<II  
} iB3+KR  
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} ~R@m!'Ik  
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: |*,Lwvd  
/* KHus/M&0  
**SiteInfoBean.java @*"<U]  
*/ /-YlC(kL  
package NetFox; /N]Ow  
&#oZ>`Qu  
)4)iANH?  
public class SiteInfoBean { `;qv}  
xFm{oJ!]&  
+Q!xEfpO;  
private String sSiteURL; //Site's URL Omh&)|Iql  
private String sFilePath; //Saved File's Path Fl+tbF  
private String sFileName; //Saved File's Name ]t*P5  
private int nSplitter; //Count of Splited Downloading File FV6he[,  
7k t7^V<  
=E}%>un  
public SiteInfoBean() `{|}LFS>  
{//nSplitter的缺省值为5 &Y>~^$`J  
//default value of nSplitter is 5  mz VuQ  
this("","","",5); A[ECa{v  
} R`C_CsXir  
"">fn(  
%cr]ZR  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) PDq}Tq  
{ 8P<UO  
sSiteURL= sURL; 9MtJo.A  
sFilePath = sPath; /IJ9_To  
sFileName = sName; FX|lhwmc(  
this.nSplitter = nSpiltter; V0'p1J tD  
.FbZVYc]  
8X ?GY8W:  
} KYRm Ui#  
!:5`im;i  
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public String getSSiteURL() aC8,Y$>?E`  
{ a,57`Ks+n<  
return sSiteURL; $|cp;~ 1  
} &Rl3y\ r  
[5p7@6:$u  
KG-k$glD  
public void setSSiteURL(String value) \,%o>M'  
{ QVG0>,+}$  
sSiteURL = value; ;c m wh<  
} itC *Z6^  
%I|+_ z&x  
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public String getSFilePath() $XQ;~i   
{ q:-]d0B+  
return sFilePath; lq\'  
} Y0L5W;iM  

Z}K.^\S9  
,+NE:_  
public void setSFilePath(String value) & GzhcW~
 
{ 8MeO U  
sFilePath = value; .i3lG( YG  
} 6h:?u4  
(w#slTFT  
5y[b8mur  
public String getSFileName() "x.6W!  
{ C{`^9J-  
return sFileName; 2iR:*}5  
} tJh3$K\  
5&-j{J0iV  
T[4[/n>i  
public void setSFileName(String value) =!g/2;-or  
{ ph8Jn
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sFileName = value; |>IUtUg\  
} ]w_  
Ukh$`q}  
ER;lkF`RF  
public int getNSplitter() /H%<oAjp6  
{ 3I;xU(rv  
return nSplitter; a*W_fxb  
} ^z*):e  
5!S
oN}$  
rTP5-4  
public void setNSplitter(int nCount) DYT@BiW{  
{ :tjgg]  
nSplitter = nCount; E~<(i':  
} 2|
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} G.-h=DT]  
q:2aPfo&  
*;OJ~zT  
/* [V> :`?  
**Utility.java )p/=u@8_f  
*/ 3WO#^}t  
package NetFox; t?]\M&i&  
+7i7`'9pd  
I=4Xv<F  
public class Utility { JVUZ}#O  
>bX-!<S  
b(.-~c('  
public Utility() Xr@l+zr  
{ ih+*T1#:(  
7]/dg*A )C  
/-
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} SE,o7_k'S  
.0n
n0)"  
//线程睡眠 ),nCq^Bp  
public static void sleep(int nSecond) iA55yT
+  
{ )(:+q(m  
try{ h*;g0QBkl  
Thread.sleep(nSecond); ill-%OPeg  
} c N02roQl  
catch(Exception e) ] ?DDCew  
{ Q(~3pt
 
e.printStackTrace (); @9}),hl`  
} krQl^~@  
} F\-B3i%0  
Je#!Wd  
//日志 ~_DF06G  
public static void log(String sMsg) NLcO{   
{ |eHwp  
System.err.println(sMsg); g9yaNelDh)  
} Veb+^&   
Lv `#zgo_f  
?1GY%-  
public static void log(int sMsg) ^lHb&\X  
{ 'GEBxNH:  
System.err.println(sMsg); ;;EDN45  
} Qqd6.F  
} pP|,7c5  
-Z:]<;qU  
/6+1{p  
/* !cq=)xR  
**TestMethod.java B#HV20\?v  
*/ +
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package NetFox; eV[`P&j_C  
P'a0CE%  
Wmzq  
public class TestMethod { !1ML%}vvB,  
cZNi~  
pwJ'3NbS  
public TestMethod() ZWf-X  
{ ///xx/weblogic60b2_win.exe :y=!{J<  
try{ k_,MoDz  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5h_<R!jA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !UBy%DN~k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jP1$qhp  
fileFetch.start(); O0@w(L-  
} 6eOrs-ty  
catch(Exception e){e.printStackTrace ();} Ze-MAt  
NJn&>/vM  
k
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} 7cIC&(h5  
-'I _*fu  
k4S} #!  
public static void main(String[] args) W[@i;f^g  
{ ,/i_QgP  
new TestMethod(); @bY('gC,  
} {F'Az1^I=  
} T#\p%w9d  
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