http断点续传简单实现（java)

/* 6y57m;JW/  
**SiteFileFetch.java `^ a:1^  
*/ teC/Uf5  
package NetFox; :Nwv&+  
import java.io.*; ` N R,8F  
import java.net.*; Q7{{r&|t&  
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public class SiteFileFetch extends Thread { E9Dy)f]#W  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :ln?PT  
long[] nStartPos; //开始位置 R3.w")6  
long[] nEndPos; //结束位置 W]_a_5  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /-t!)_zvw  
long nFileLength; //文件长度 )X:Sfk  
boolean bFirst = true; //是否第一次取文件 3x7fa^umR  
boolean bStop = false; //停止标志 5wha _Yet  
File tmpFile; //文件下载的临时信息 I+SfZ:q^  
DataOutputStream output; //输出到文件的输出流 <#199`R  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） D>
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public SiteFileFetch(SiteInfoBean bean) throws IOException B&y?Dc  
{ r!w*y3  
siteInfoBean = bean; %tC[q   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Iza;~8dH5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SGba6b31  
if(tmpFile.exists ()) {P\Ob0)q  
{ i)$
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bFirst = false; eibkG  
read_nPos(); 0>D*d'xLd  
} uFhPNR2l  
else jTZi< Y:bB  
{ 9j5|o([J  
nStartPos = new long[bean.getNSplitter()]; GoH.0eQ^  
nEndPos = new long[bean.getNSplitter()]; o|c&$)m  
} 5wE6gRJ  
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} }NRt:JC  
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public void run() -dN`Ok<g  
{ ~l.C
-  
//获得文件长度 59v=\; UI  
//分割文件 UV av^<_  
//实例FileSplitterFetch (Q ^=^s|  
//启动FileSplitterFetch线程 w5rtYTI  
//等待子线程返回 6c27X/'Z  
try{ \ bWy5/+  
if(bFirst) wZbT*rU  
{ $sZ4r>-  
nFileLength = getFileSize(); gB+CM? LKq  
if(nFileLength == -1) ygX!'evY  
{ c* ~0R?  
System.err.println("File Length is not known!"); *~cNUyd  
} Ux{QYjFE  
else if(nFileLength == -2) ~X %cbFom=  
{ 2']0c z  
System.err.println("File is not access!"); qu]a+cYY  
} 
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else R/Sm  
{ [u J<]  
for(int i=0;i<nStartPos.length;i++) [D(JEO@ :  
{ V$;`#J$\b  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); e6qIC*C!  
} O U9{Y9e  
for(int i=0;i<nEndPos.length-1;i++) r2PN[cLu|  
{ (2"4PU8  
nEndPos = nStartPos[i+1]; YcR: _ac  
} VkJTcC:1  
nEndPos[nEndPos.length-1] = nFileLength; z|Xt'?9&n  
} 3-n&&<  
} \$t{K  
NwQ$gDgu t  
";jAHGbO  
//启动子线程 D&@ js!|5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b j<T`M!  
for(int i=0;i<nStartPos.length;i++) NNTrH\SU#  
{ wdV)M?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0"
+QWh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;- Vs|X  
nStartPos,nEndPos,i); hp}rCy|01  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {!{T,_ J  
fileSplitterFetch.start(); /X#OX8gb]  
} D62'bFB^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N"Y%*BkH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); mUR[;;l  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?duw0SZ  
nEndPos = " + nFileLength); glKPjL*  
// fileSplitterFetch[nPos.length-1].start(); Vhb~kI!x  
b}u#MU  
[xDIK8d:I  
//等待子线程结束 9)j"|5H  
//int count = 0; KBI1t$  
//是否结束while循环 <Nc9F['&#  
boolean breakWhile = false; *laFG<;  
99]s/KD2yb  
KVViTpZ  
while(!bStop) ,'l.u?SKyd  
{ (4`Tf*5hHa  
write_nPos(); h\Zh^B6J  
Utility.sleep(500); !y!s/i&P%  
breakWhile = true; @cm[]]f'l  
^r]-v++  
2!{_x8,n  
for(int i=0;i<nStartPos.length;i++) ,5K&f\  
{ 9jl\H6JY|  
if(!fileSplitterFetch.bDownOver) |c-`XC2g  
{ gB,Q4acjj  
breakWhile = false; 4xFAFK~lx
 
break; a"1LF`  
} miCY?=N`  
} 7Bf4ojKt  
if(breakWhile) @e7_&EGR?  
break; fg1uqS1rg  
hKsx7`[  
f)Z'#[A*t7  
//count++; X\<a|/{V A  
//if(count>4) Y!|};  
// siteStop(); ?q5HAIZ`  
} JKCV>k  
Vt9o8naz  
)coA30YR  
System.err.println("文件下载结束！"); Th~pju  
} (ueH@A"9;  
catch(Exception e){e.printStackTrace ();} 6Hd^qouid  
} D6e<1W  
*1>Tc,mb  
_F8-4  
//获得文件长度 :b#5cMUe  
public long getFileSize() $.B}zY{  
{ ~ r$I&8  
int nFileLength = -1; _qQo}|/q  
try{ :n x;~f  
URL url = new URL(siteInfoBean.getSSiteURL()); u/\
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); otP2qAI  
httpConnection.setRequestProperty("User-Agent","NetFox"); )S_%Ip  
)MX%DQw  
%U1HvmyK  
int responseCode=httpConnection.getResponseCode(); Ja@?.gW  
if(responseCode>=400) C|QJQ@bj0  
{ :+ "JPF4X  
processErrorCode(responseCode); A+3=OBpkW0  
return -2; //-2 represent access is error rj5)b:c}  
} h 'is#X 6:  
^AUQsRA7PZ  
#`"B YFV[E  
String sHeader; ab6D&  
Mq6_Q07  
`]Vn[^?D  
for(int i=1;;i++) EkN>5).  
{ gJzS,g1]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kaC
n@$  
//Utility.log(in.readLine()); W*4!A\K  
sHeader=httpConnection.getHeaderFieldKey(i); er!+QD,EM  
if(sHeader!=null) CR|>?9V  
{ `R$bx 64  
if(sHeader.equals("Content-Length")) {Z[kvXf"mZ  
{ \l 3M\$oS>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `k08M)  
break; TR{dNO!q  
} ayA_[{j%X  
} [@s5v  
else bW'Y8ok[v  
break; / pR,l5  
} 'FN3r  
} r8L'C  
catch(IOException e){e.printStackTrace ();} ^}GR!990  
catch(Exception e){e.printStackTrace ();} H329P*P  
q?&JS  
[3W+h1  
Utility.log(nFileLength); @jD19=  
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]6HnK%  
return nFileLength; Q $>SYvW  
} HYg7B  
i{>YQ  
wtGb3D"am  
//保存下载信息（文件指针位置） Lismo#  
private void write_nPos() a.AEF P4N  
{ a3(f\MMxE  
try{ y? 65*lUl  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /p@0Q[E  
output.writeInt(nStartPos.length); MK4CggoC  
for(int i=0;i<nStartPos.length;i++) '}NH$ KA  
{ c-
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// output.writeLong(nPos); f<3r;F7  
output.writeLong(fileSplitterFetch.nStartPos); #DHeEE  
output.writeLong(fileSplitterFetch.nEndPos); niM(0p  
} :SpPT  
output.close(); ]^l-k@  
} Xc]Q_70O  
catch(IOException e){e.printStackTrace ();} Qp>Q-+e0  
catch(Exception e){e.printStackTrace ();} H0mDs7  
} _n< @Jk~  
9}Zi_xK&|e  
E}=F   
//读取保存的下载信息（文件指针位置） ~3m} EL  
private void read_nPos() 'MIM_m)H  
{ <4Cy U j  
try{ {pB9T3ry]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v#+tu,)V;  
int nCount = input.readInt(); 2VS#=i(B^  
nStartPos = new long[nCount]; ia/_61%  
nEndPos = new long[nCount]; {{_,YO^w  
for(int i=0;i<nStartPos.length;i++) 4:v{\R  
{ h'
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nStartPos = input.readLong(); & |o V\L  
nEndPos = input.readLong(); -3:x(^|:K  
} YcBAW4B`  
input.close(); rx;zd?  
} k$} 6Qd  
catch(IOException e){e.printStackTrace ();} WR"p2=  
catch(Exception e){e.printStackTrace ();} x68s$H  
} ~# |p=Y  
/d-7n|#E  
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private void processErrorCode(int nErrorCode) rk(0w|zR+  
{ FKB)o7  
System.err.println("Error Code : " + nErrorCode); cj/FqU"  
} 5=Y\d,SS"  
S b3@7^  
pF"IDC  
//停止文件下载 O8ZHI
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public void siteStop() PK* $  
{ .{W)E  
bStop = true; sWnU*Q  
for(int i=0;i<nStartPos.length;i++) YEqWTB|w  
fileSplitterFetch.splitterStop(); Bhrp"l +|  
U9B|u`72  
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} /=qn1  
} u5FlT3hY.  
//负责部分文件的抓取 = 8%+$vX  
**FileSplitterFetch.java bx<7@  
*/ /P|jHK|{  
package NetFox; RA+k/2]y!  
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import java.io.*; [(N<E/m%B  
import java.net.*; Wc$1Re{z  
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 `#lNur\x  
public class FileSplitterFetch extends Thread { ^T|~L
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p(Q5!3C0q  
_\LAWQ|M4[  
String sURL; //File URL vH#^|u  
long nStartPos; //File Snippet Start Position <[7.+{qfW  
long nEndPos; //File Snippet End Position f"5vpU^5*  
int nThreadID; //Thread's ID [nlW}1)46  
boolean bDownOver = false; //Downing is over QY<2i-A  
boolean bStop = false; //Stop identical X^H)2G>e  
FileAccessI fileAccessI = null; //File Access interface Dl%NVi+n  
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m.p{+_@M&  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8+1tys  
{ 7>J8\=  
this.sURL = sURL; #\$R^u]!  
this.nStartPos = nStart; 5!G}*u.  
this.nEndPos = nEnd; I%whM~M1+  
nThreadID = id; 3s
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 LdA
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} "tbKKh66  
/%U+kW  
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public void run() !285=cxz  
{ wvA@\-.+  
while(nStartPos < nEndPos && !bStop) amIG9:-1'  
{ v>71?te  
@DrMaTr  
/E@|  
try{ $R7n1  
URL url = new URL(sURL); ?8n`4yO0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n
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httpConnection.setRequestProperty("User-Agent","NetFox"); Uok?FEN  
String sProperty = "bytes="+nStartPos+"-"; 7!`,P  
httpConnection.setRequestProperty("RANGE",sProperty); Nd*zSsVlq  
Utility.log(sProperty); M:qeqn+  
,xrXby|R"  
?y7x#_Exc  
InputStream input = httpConnection.getInputStream(); `2?9eXC  
//logResponseHead(httpConnection); nj~1y')  
{ls$#a+d  
^~2GhveBV  
byte[] b = new byte[1024]; 0t1WvW  
int nRead; )sVz;rF<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5/Q^p"  
{ <ok/2v
 
nStartPos += fileAccessI.write(b,0,nRead); b$+.}&M  
//if(nThreadID == 1)
0Q=4{*:?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A5zT^!`
[  
} 'tp1|n/1  
fNc3&=]]  
LzS@@']  
Utility.log("Thread " + nThreadID + " is over!"); RUmJ=i'4/  
bDownOver = true; ZUb6d*B  
//nPos = fileAccessI.write (b,0,nRead); }Z-]m  
} hd.^ZD7  
catch(Exception e){e.printStackTrace ();} v3Y/D1jd"  
} *.AokY)_a  
} 4QZ -
7_  
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&'UYV>  
//打印回应的头信息 aO?(ZL  
public void logResponseHead(HttpURLConnection con) e/EfWwqt  
{  tQB+_q z  
for(int i=1;;i++) ~&=-*  
{ }N1Z7G  
String header=con.getHeaderFieldKey(i); jx&pRjP  
if(header!=null) #z)@T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); i3*S`/]p  
Utility.log(header+" : "+con.getHeaderField(header)); ";cWK29\f  
else nW3`Z1kq})  
break; ?C6iJnm  
} ]n0kO&  
} vW 0m%  
6yKr5tH4  
6e$(-ai  
public void splitterStop() wGE:U`
 
{ A
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bStop = true; 1GVJ3VXt  
} E@aR5S>  
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_* ]~MQ=  
} n3-u.Fb  
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)  
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/* [J0L7p*6  
**FileAccess.java Iw8;",e2  
*//文件访问(定位，写) tB4- of3+  
package NetFox; a5:Q%F<!  
import java.io.*; Zg%U4m:  
l~wx8 ,?G  
;=Jj{FoG%  
public class FileAccessI implements Serializable{ Slcf=  
DHJh.Y@H  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 agN`) F!  
RandomAccessFile oSavedFile; >sdj6^[+  
long nPos; {=j!2v#8~  
a0Cf.[L  
b40zYH`'{  
public FileAccessI() throws IOException 5@bLDP  
{ s(J,TS#I]  
this("",0); B0NK
av  
} #Na3eHT  
tWD~|<\. )  
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public FileAccessI(String sName,long nPos) throws IOException W`K XO|'p@  
{ r}MXXn,f  
oSavedFile = new RandomAccessFile(sName,"rw"); ` ZXX[&C  
this.nPos = nPos; (Kd;l&8  
oSavedFile.seek(nPos); &F*s.gL  
} B@` 87  
at${^,&  
z@^[.  
public synchronized int write(byte[] b,int nStart,int nLen) meT~b  
{ C] qY  
int n = -1; 2f16 /0J@  
try{ 7^#f<m;Ar!  
oSavedFile.write(b,nStart,nLen); eyy{z;D8r  
n = nLen; ]`4QJ;#  
} ))KsQJ"
V  
catch(IOException e) NX=dx&i>+  
{ 9hguC yr@h  
e.printStackTrace (); ~r>UjC_ B:  
} /Cg/Rwl  
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L0_=R;.<  
return n; 0~S<}N  
} mMjVbeh[  
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} =p7W^/c  
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/* r2Z`4tN:  
**SiteInfoBean.java sNZPv^c  
*/ pF!vW  
package NetFox; *{Z!m@?  
Y zvtxX*  
<1LuYEDq  
public class SiteInfoBean { qnm9Lw#  
rFK *  
C4cg,>P7  
private String sSiteURL; //Site's URL PQ(%5c1e  
private String sFilePath; //Saved File's Path *|3z($*U]  
private String sFileName; //Saved File's Name v4.V%tg!  
private int nSplitter; //Count of Splited Downloading File O71rLk;  
T6,lk1S'=  
0ND7F  
public SiteInfoBean() O0l;
Qi  
{//nSplitter的缺省值为5 ixH7oWH#  
//default value of nSplitter is 5 K*}j1A  
this("","","",5); a$|u!_)!h  
} :OZhEBL&b  
U{}7:&As  
Z"^@B2v  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) enrmjA&3  
{ mT9
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sSiteURL= sURL; 68>zO%  
sFilePath = sPath; ?d0Dfqh_  
sFileName = sName; :
)yM9^<D  
this.nSplitter = nSpiltter; ^KF'/9S  
>k#aB.6  
{2Ibd i  
} ;5l|-&{@*  
[eN{
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,5?MRqCM  
public String getSSiteURL() W!^=)Qs  
{ w#$k$T)  
return sSiteURL; J|q_&MX/  
} mNYz7N  
_L72Ae(_  
xd.C&Dx5  
public void setSSiteURL(String value) Ol@ZH_  
{ [P,nW/H  
sSiteURL = value; u^uG_^^,
/  
} ZM.g+-9  
q<8HG_  
D-!%L<<  
public String getSFilePath() OR9){qP  
{ J)-> 7h=  
return sFilePath; f5-={lUlIS  
} gD\}CxtG  
'W*F[U*&HP  
eH8
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public void setSFilePath(String value) ZIl<y
{  
{ [ub\DLl  
sFilePath = value; y^rg%RV  
} F)w83[5_d  
\#r_H9&s6  
2cl~Va=  
public String getSFileName() 9="sx 8?  
{ B$Z!E%a;  
return sFileName; S@)bl  
} (ce NVo&  
>cb gL%
 
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public void setSFileName(String value) h_L '_*  
{ pH[lj8S  
sFileName = value; ;gnr\C*G  
} R2`g?5v  
j[cjQ]>~'  
Ke'2"VkQt  
public int getNSplitter() `.g8JC\_m  
{ zOdKB2_J7  
return nSplitter; $O8V!R*  
} !X8R  
)}!'VIe^!  
*Rh .s!@4  
public void setNSplitter(int nCount) Fw m:c[G  
{ \k_3IP?o=  
nSplitter = nCount; uLljM{I  
}
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} ;hJ*u  
mU$7_7V~  
-RQQ|:O$  
/* EIQy?ig86  
**Utility.java vP?S0>gh  
*/ `&zobbwq  
package NetFox; `kSCH; mwP  
 eb@L
h!  
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public class Utility { zEfD{I  
0 _}89:-  
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public Utility() |qDfFGYf  
{ 6CRPdLTDf  
7=A9E]:  
*AR<DXEL  
} -yGm^EwP  
1>y=i+T/b  
//线程睡眠 /,Id_TTCO  
public static void sleep(int nSecond) 'a?.X _t  
{ $ow`)?sh  
try{ F)kLlsp  
Thread.sleep(nSecond); wLe&y4  
} vXQmEIm  
catch(Exception e) <# r.}T.l  
{ 7h/Q;P5  
e.printStackTrace (); 0]W]#X4A  
} +STzG/9#  
} 72vGfT2HtZ  
=e-aZ0P  
//日志 x>"JWD  
public static void log(String sMsg) TbAdTmW  
{ XPo'iI-  
System.err.println(sMsg); igj@{FN  
} *"{Z?< 3  
\1C!,C  
bk9~63tN+>  
public static void log(int sMsg) .hNw1~Fj  
{ N:jiZ)  
System.err.println(sMsg); T8TsKjqOZ  
} :gaeb8`t  
} |Umfq:W`y_  
DB'KIw  
x0$:"68PW  
/* 6ilC#yyp  
**TestMethod.java /1#Q=T  
*/ 4qXRDsbCf  
package NetFox; '=G Ce%A  
cY
y@  
A<CXdt+t  
public class TestMethod { ff./DMDafI  
cBR8HkP~  
R6Z}/m  
public TestMethod() Is6 _  
{ ///xx/weblogic60b2_win.exe l@/kPEh  
try{ [pFu ]^X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xp8f  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _JIU
ds5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4yZ+,hqJ<9  
fileFetch.start(); IetGg{h.  
} VD&3%G!  
catch(Exception e){e.printStackTrace ();} ?[1qC=[Z<  
15T[J%7
f  
G$|;~'E  
} UQ?OD~7  
[67E5rk-  
6 %k+
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public static void main(String[] args) :`^3MMLO  
{ =*:_swd  
new TestMethod(); !"x7re  
} #iU8hUbo  
} ?r E]s!K  
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