http断点续传简单实现（java)

/* WI{;#A  
**SiteFileFetch.java =-5[Hn%  
*/ >9MS"t  
package NetFox; I3PQdAs~&h  
import java.io.*; *x!LKIpv  
import java.net.*; ?^. Pt  
8 ip^]  
"O``7HA}  
public class SiteFileFetch extends Thread { DL1 +c`d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean sjn:O'  
long[] nStartPos; //开始位置 ?aFZOc4   
long[] nEndPos; //结束位置 5aG5BA[N  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (2tH"I  
long nFileLength; //文件长度 },s_nJR:8  
boolean bFirst = true; //是否第一次取文件 xj7vI&u.  
boolean bStop = false; //停止标志 n$xszuNJ`  
File tmpFile; //文件下载的临时信息 MOeoU1Hn  
DataOutputStream output; //输出到文件的输出流 ZJvo9!DL|  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5VZjDg?  
public SiteFileFetch(SiteInfoBean bean) throws IOException =|"=l1  
{ w&5/Zh[~~L  
siteInfoBean = bean; ntZ~m  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "[.ne)/MC  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +KP_yUq[  
if(tmpFile.exists ()) fK"iF@=Z`  
{ {[tZ.1.w  
bFirst = false; #Z0-8<\  
read_nPos(); (kY@7)d'e  
} 9DPb|+O-  
else %N1"*</q  
{ djGs~H>;U_  
nStartPos = new long[bean.getNSplitter()]; cWM:  
nEndPos = new long[bean.getNSplitter()]; 5NFRPGYX  
} a%*_2#  
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} P7UJ-2%Y+  
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public void run() f"P$f8$  
{ _A3X6  
//获得文件长度 U=DEV7E  
//分割文件 Zw24f1iY  
//实例FileSplitterFetch 8i[LR#D)  
//启动FileSplitterFetch线程 N|<bVq%  
//等待子线程返回 [<S^c[47U  
try{ | k}e&Q_/G  
if(bFirst) t}~UYG(h~  
{ #Cx%OIi[f  
nFileLength = getFileSize(); Ld~q1*7J  
if(nFileLength == -1) ?BsH{QRYQ  
{ Wc\+x1:8  
System.err.println("File Length is not known!"); ZB0+GG\  
} S<pk
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else if(nFileLength == -2) 2vvh|?M  
{ z7k$0&  
System.err.println("File is not access!"); 
P5P<"  
} tR;{.  
else q5?{1  
{ O5OXw]  
for(int i=0;i<nStartPos.length;i++) }hq^+fC?  
{ Y/D-V  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); HU9p!I.  
} `x2,;h!:)N  
for(int i=0;i<nEndPos.length-1;i++) ~1ps7[  
{ >f%,`r  
nEndPos = nStartPos[i+1]; JhH`uA&  
} 3.FR C  
nEndPos[nEndPos.length-1] = nFileLength; u#3)p  
} 1daL y  
} -=sf}4A  
Q1]Wo9j  
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//启动子线程 O]bKNA.5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f:XfAH3R{  
for(int i=0;i<nStartPos.length;i++) X|Dpt2A=  
{ 0e\y~#-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j/' g$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;h9W\Se  
nStartPos,nEndPos,i); z{/LX \  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tvT4S  
fileSplitterFetch.start(); B%mtp;) P  
} `0z/BCNB  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B.RRdK+:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); y;r"+bS8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ko+al{2  
nEndPos = " + nFileLength); `yYvYc
 
// fileSplitterFetch[nPos.length-1].start(); K( z[}  
y+RRg[6|  
69iM
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//等待子线程结束 xl9(ze  
//int count = 0; :G0+;[?N  
//是否结束while循环 fyrd`R  
boolean breakWhile = false; >j:|3atb  
cd+^=esSO  
DyIV/  
while(!bStop) -!~vA+jw1  
{ OW#_ty_ul  
write_nPos(); %",ULtZ+  
Utility.sleep(500); ]zcV]Qj$~  
breakWhile = true; bM5CDzH(#X  
lz}llLb1  
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for(int i=0;i<nStartPos.length;i++) !-ZP*V3}h  
{ C/  
if(!fileSplitterFetch.bDownOver) *_#&"(P  
{ zWtj|%ts  
breakWhile = false; 9cz)f\  
break; .aJ%am/:%  
} 7jT#BWt  
} =E1tgrW  
if(breakWhile) {KsVK4\r  
break; T\fudmj&  
Az9J\V~"  
b*`fLrqV.  
//count++; CC>($k"  
//if(count>4) 0Gx*'B=  
// siteStop(); CWBbSGk  
} ,# eO&  
Lrlk*   
s.KOBNCFa  
System.err.println("文件下载结束！"); /k) NP  
} jceHKl  
catch(Exception e){e.printStackTrace ();} p
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} 8:<1|]]  
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W#VfX!~  
//获得文件长度 [NjajA~z>F  
public long getFileSize() 8;0^'Qr8  
{ ~T7\8
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int nFileLength = -1;
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try{ O'fc/cvh='  
URL url = new URL(siteInfoBean.getSSiteURL()); M&OsRrq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); pLPd[a  
httpConnection.setRequestProperty("User-Agent","NetFox"); Yx!n*+:J  
s<,"Hsh^CR  
jOtzx"/)rE  
int responseCode=httpConnection.getResponseCode(); N" ;^S  
if(responseCode>=400)
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{ K)Ge  
processErrorCode(responseCode); -CwWs~!  
return -2; //-2 represent access is error $6Z[|9W^A  
} ah>Dqb*  
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sZT VM9<)  
String sHeader; cmae&Atotw  
*%nX#mwz  
ONNW.xHp  
for(int i=1;;i++) 'h k @>"  
{ so'eZ"A:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); aC4m{F[  
//Utility.log(in.readLine()); pIL`WE1'  
sHeader=httpConnection.getHeaderFieldKey(i); ijg,'a~3E  
if(sHeader!=null) w2' 3S#nZ  
{ |NXFla  
if(sHeader.equals("Content-Length")) L^&do98  
{ 4">84,-N  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); eZ[#+
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break; iKY-;YK  
} I ;l`VtD  
} >"i~ x  
else N4tc V\O  
break; IK85D>00T  
} \/pVcR  
} N0=b[%g;n  
catch(IOException e){e.printStackTrace ();} E|\3f(aF  
catch(Exception e){e.printStackTrace ();} V`U/'N-ay  
b\H/-7<  
/oBK&r[(  
Utility.log(nFileLength); Gtf1}UJC  
2
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- f+CyhR"*  
return nFileLength; k#BU7Exij  
} uLF\K+cz  
3$;J0{&[i  
ud5x$`  
//保存下载信息（文件指针位置） r*xq(\v  
private void write_nPos() S|tA[klh  
{ l8eT{!4  
try{ UX03"gX  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *pmoLiuB>  
output.writeInt(nStartPos.length); nsy!p5o  
for(int i=0;i<nStartPos.length;i++) zR_9D}  
{ ^o,y5,  
// output.writeLong(nPos); ;H`=):U  
output.writeLong(fileSplitterFetch.nStartPos); Ti /;|lP@  
output.writeLong(fileSplitterFetch.nEndPos); ,80jMs  
} f45x%tha%  
output.close(); tPQ2kEW  
} }6F_2S3c  
catch(IOException e){e.printStackTrace ();} NWaI[P
 
catch(Exception e){e.printStackTrace ();} `>$gy/N  
} xtG)^x!  
$eTv6B?m  
}Z<D^Z~w  
//读取保存的下载信息（文件指针位置） r@\,VD6J  
private void read_nPos() 3ZLr"O1l)  
{ DX7Ou%P,mg  
try{ PpI+@:p[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K#%O3RRs  
int nCount = input.readInt(); Ov F8&*A  
nStartPos = new long[nCount]; EG8%~k+R  
nEndPos = new long[nCount]; Fa Qu$q  
for(int i=0;i<nStartPos.length;i++) HE8'N=0  
{ *)2x&~T*|  
nStartPos = input.readLong(); qQ3]E][/  
nEndPos = input.readLong(); g9RzzE!  
} Djg1Qh  
input.close(); ,K"r:)\  
} 6yV5Yjs  
catch(IOException e){e.printStackTrace ();} =P@M&Yy'  
catch(Exception e){e.printStackTrace ();} ";%e~ =  
} :T8u?@.  
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private void processErrorCode(int nErrorCode) vY8WqG]  
{ ^' edE5  
System.err.println("Error Code : " + nErrorCode); cN0~;!{i  
} X
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h Kp,4D>2_  
^^20vwq  
//停止文件下载 )m$1al  
public void siteStop() /1s9;'I  
{ AIIBd  
bStop = true; eUGmns  
for(int i=0;i<nStartPos.length;i++) !07FsPI#{  
fileSplitterFetch.splitterStop(); A=\'r<:  
*+4>iL*:  
f=-!2#%  
} zM3H@;}m  
} ;@h'Mb  
//负责部分文件的抓取 ][T9IAn  
**FileSplitterFetch.java fJ|Bu("N  
*/ 3"2<T^H]  
package NetFox; n]kQ
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fS8XuT  
_ d(Ks9  
import java.io.*; 9OO0Ht4j  
import java.net.*; i75?*ld  
`"^@[1  
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public class FileSplitterFetch extends Thread { x0TnS#  
*IjdN,wox  
^Y*`D_-G  
String sURL; //File URL f6(9wz$Trt  
long nStartPos; //File Snippet Start Position jSOa   
long nEndPos; //File Snippet End Position q_%w l5\F  
int nThreadID; //Thread's ID Y'+F0IZ+  
boolean bDownOver = false; //Downing is over 8xeun~e"vS  
boolean bStop = false; //Stop identical *R9mgv[  
FileAccessI fileAccessI = null; //File Access interface oK(W)[u  
VygXhh^7\  
c DEe?WS  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~I8"l@H>  
{ q^T&A[hMPx  
this.sURL = sURL; P"h,[{Y*>  
this.nStartPos = nStart; 8O;rp(N.n  
this.nEndPos = nEnd; }SJLBy0  
nThreadID = id; sbq44L)  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wKeSPs{x  
} S|=rF<]my  
f(9$"Vi  
gzJ{Gau{)  
public void run() 0N} wD-  
{ hoSU`X  
while(nStartPos < nEndPos && !bStop) }y-AoG  
{ 4,R\3`b  
?L~=Z\H  
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try{ \e5,`  
URL url = new URL(sURL); JVIcNK)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "8C(_z+]K`  
httpConnection.setRequestProperty("User-Agent","NetFox"); OA8b_k~  
String sProperty = "bytes="+nStartPos+"-"; F~uA-g  
httpConnection.setRequestProperty("RANGE",sProperty); %l]rQjV-  
Utility.log(sProperty); `)gkkZ$)j  
!]jNVg  
* zJiii  
InputStream input = httpConnection.getInputStream(); M%Kx{*aw&  
//logResponseHead(httpConnection); 'piF_5(@  
Hhce:E@K  
b$$L]$q2  
byte[] b = new byte[1024]; 6r-<XNv)0  
int nRead;  zxynEdO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xVwi }jtG|  
{ cvLcre% >A  
nStartPos += fileAccessI.write(b,0,nRead); 4)>\rqF+v  
//if(nThreadID == 1) hnfrnYH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QeOt;{_|  
} S92!jp/  
MM58w3Mz
 
#dn%KMo2r  
Utility.log("Thread " + nThreadID + " is over!");
$BO}D  
bDownOver = true; EF7|%N  
//nPos = fileAccessI.write (b,0,nRead); fAA@ziKg  
} ss M9t  
catch(Exception e){e.printStackTrace ();} d9e H}#OY  
} JwG5#CFu^  
} e^l+#^fR  
N4GIb 6  

uzn))/"  
//打印回应的头信息 /EAQ.vxI  
public void logResponseHead(HttpURLConnection con) l8n[8AT1  
{ ]qP}
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for(int i=1;;i++) ?
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{ #.t$A9'  
String header=con.getHeaderFieldKey(i); u3?Pp[tM<  
if(header!=null) MdTd$ 4J3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )*QTxN  
Utility.log(header+" : "+con.getHeaderField(header));  "lnk  
else + 1%^c(3  
break; =jd=Qs IL
 
} pa> 2JF*  
} 1_E3DXe  
:92a34  
~4 xBa:*z  
public void splitterStop() (k HQKQmq  
{ YI(OrR;V  
bStop = true; H fmMf^c  
} BrH`:Dw  
}Us
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} $!3t$-TSD  
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+M%2m3.Jo  
/* !v;_@iW3e  
**FileAccess.java +H^V},dBp!  
*//文件访问(定位，写) qFsg&<  
package NetFox; o4 OEA)k)=  
import java.io.*; Y Z2VP  
j!8+|eAkk  
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public class FileAccessI implements Serializable{ L"^366M!  
0 Ln5e.&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1R~
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RandomAccessFile oSavedFile; |"E9DD]{  
long nPos; YGO7lar  
r#w_=h)  
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public FileAccessI() throws IOException s/&]gj"  
{ `j"G=%e3.  
this("",0); G78j$ ^/0  
} %_=R&m'n`  
fvfVBk#  
o 0 #]EMr  
public FileAccessI(String sName,long nPos) throws IOException U$JIF/MO_  
{ WsDe0F  
oSavedFile = new RandomAccessFile(sName,"rw"); >\x 39B  
this.nPos = nPos; X|B;>q
 
oSavedFile.seek(nPos); I\6<)2j/L  
} DT]p14@t9  
:mHtK)z~  
pPoC61F  
public synchronized int write(byte[] b,int nStart,int nLen) ]M"'qC3g  
{ Lj1 @yokB  
int n = -1; J0W).mD_H  
try{ TK?+O}v-]!  
oSavedFile.write(b,nStart,nLen); !OVEA^6  
n = nLen; kxf=%<l  
} s^@Cq=  
catch(IOException e) ?Pw\&q  
{ _5`S)G{  
e.printStackTrace (); X',0MBQ0  
} q _|5,_a  
?v~3zHK  
0!\q
  
return n; 7Cp_41._  
} 0BD((oNg  
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9+Hb`  
} To? bp4  
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zW`koRH@  
/* U+M?<4J)"  
**SiteInfoBean.java ]+7c1MB(5  
*/ O +}EE^*a  
package NetFox; Rw8m5U  
Q31c@t  
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public class SiteInfoBean { 9yAu<a  
1Sk6[h'CL  
r@UY$z  
private String sSiteURL; //Site's URL M.^A`  
private String sFilePath; //Saved File's Path `bF;Ew;  
private String sFileName; //Saved File's Name =_6h{f&Q  
private int nSplitter; //Count of Splited Downloading File ?O Nw*"9  
y.<Y]m  
3m7V6##+  
public SiteInfoBean() 5FKd{V'  
{//nSplitter的缺省值为5 {# _C  
//default value of nSplitter is 5 f+~!s 2uw  
this("","","",5); ; O0rt1  
} -RDs{c`y%N  
@&yj7-]  
ebK wCZwK*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) agD.J)v\  
{ MCG~{#`  
sSiteURL= sURL; Q kpmPQK  
sFilePath = sPath; HN@)/5BY  
sFileName = sName; a/#,Y<kJ  
this.nSplitter = nSpiltter; UH|.@7w  
BQg]$Tr?  
gP%!  
} @!O{>`  
:[03upyS  
|:[vpJFK  
public String getSSiteURL() uelTsn  
{ +N_%|!F-c  
return sSiteURL; 'A2"&6m)28  
} _8`
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VbR.tz  
0+i,,^x.  
public void setSSiteURL(String value) +[`%b3Nk  
{ 5~0;R`D  
sSiteURL = value; 1`\kXaG  
} Mp=+*I[  
RtL'fd  
_3[BS9  
public String getSFilePath() 6s2g+[  
{ Ma#-'J  
return sFilePath; m/Z_HER^  
} hh}EDnx  
NZP,hAUK,  
B[V=l<J  
public void setSFilePath(String value) _,~zy9{,  
{ f'U]Ik;Jy  
sFilePath = value; e[!>ezaIY  
} eO G%6C%a  
)>p6h]]a  
>FNt*tX<0  
public String getSFileName() "FS.&&1(  
{ L9)&9 /f  
return sFileName; |pY0IqO  
} RoRVu,1  
iKY&gnu"  
_AHVMsz@  
public void setSFileName(String value) YfKty0  
{ V|7CYkB8  
sFileName = value; 4/|=0TC;  
} UMaKvr-C&  
KW<CU'  
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public int getNSplitter() -Ma"V  
{ tEs$+b  
return nSplitter; ZeZwzH)BD  
} =T]OYk  
")OLmkC  
$ 1ZY Vw  
public void setNSplitter(int nCount) ]"6<"1)  
{ L+L9)8FJ  
nSplitter = nCount; 06$9Uz9  
} P0=F9`3wb  
} h@d m:=ul  
= xk@Q7$  
5WYU&8+]{:  
/* DM95Il[/  
**Utility.java uX[

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*/ Ex3woT-  
package NetFox; +n dyR  
r N7"%dx  
HV(Kz  
public class Utility { Jt8 v=<@  
!Ao
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public Utility() p'*UM%@SIY  
{ 9iE66N>z  
_JH6bvbQ  
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} x7?{*
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r
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//线程睡眠 Xk$lQMwZ  
public static void sleep(int nSecond) .w~USJ=X  
{ tDo0Q/`  
try{ ;+U9;  
Thread.sleep(nSecond); T_WQzEL^  
} nC^'2z  
catch(Exception e) uM8gfY)OI  
{ 9D,&)6  
e.printStackTrace (); Up&q#vqIj  
} E_oe1C:  
} U?QO'H5  
rL=$WxdPU  
//日志 j*{bM{~T<  
public static void log(String sMsg) cx|j _5%i  
{ $/H'Dt6x  
System.err.println(sMsg); G.}yNjL8  
} @w0[5ZAj  
(EX  
w3@te\  
public static void log(int sMsg) x-<dJ}`  
{ qJ@?[|2R  
System.err.println(sMsg); $H
^6I8>  
} heWb(E&  
} ,l6W|p?ZO^  
KB5{l%>  
|zMQe}R@%  
/* 8~i@7~ J  
**TestMethod.java VA0TY/{ ]  
*/ !Xm:$KH  
package NetFox; 7}Sw(g)o7  
Q$%@.@  
|1D`
v9  
public class TestMethod { nCrNZ&P  
Mw~?@Sq  
AZa3!e/1  
public TestMethod() kBzzi^cl  
{ ///xx/weblogic60b2_win.exe gT.-Cf{  
try{ o;.-I[9h]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r2G<::<zL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ezn>3?S  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ut+mm\7  
fileFetch.start(); bA)Xjq)Rr  
} ^?2txLv,6  
catch(Exception e){e.printStackTrace ();} [3.rG!Na  
HIF]c  
1f=L8Dr  
} Vr*t~M>  
1}6pq2  
-cKR15  
public static void main(String[] args) F,sT[C  
{ sR6(8  
new TestMethod(); aqB^ %e  
} 0e7!_/9  
} YblRwic  
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