http断点续传简单实现（java)

/* `iQqh
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**SiteFileFetch.java 0bSz4<}  
*/ u7#z^r  
package NetFox; 3~<}bee5|q  
import java.io.*; i.M2E$b|  
import java.net.*; GI_DhU]~)  
:Y^I]`lR"  
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public class SiteFileFetch extends Thread { a_{6Qdl  
1eD.:_t4  
:<%vE!$  
SiteInfoBean siteInfoBean = null; //文件信息Bean c3#q0Ma  
long[] nStartPos; //开始位置 Vo >Xp  
long[] nEndPos; //结束位置 ="3,}qR  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (bvoF5%  
long nFileLength; //文件长度 J=9#mOcg"  
boolean bFirst = true; //是否第一次取文件 SK-W%t  
boolean bStop = false; //停止标志
@[v8}D  
File tmpFile; //文件下载的临时信息 @RVOXkVo  
DataOutputStream output; //输出到文件的输出流 !+KhFC&Py  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {(Fe7,.S3  
public SiteFileFetch(SiteInfoBean bean) throws IOException Jn#K0(FQ  
{ ] D6|o5  
siteInfoBean = bean; lkwh'@s.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k!owl+a   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;{Jb6'K1
h  
if(tmpFile.exists ()) ^mfjn-=3  
{ U0IE1_R  
bFirst = false; u(2BQO7  
read_nPos(); ]7vf#1i<  
} 7=3O^=Q^Q  
else hy!6g n  
{ n|C|&  
nStartPos = new long[bean.getNSplitter()]; `< Yf{'*  
nEndPos = new long[bean.getNSplitter()]; "-0;#&!  
} &D*8l?A/1f  
9^\hmpP@D  
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W_}/O'l{  
} '\t7jQ
 
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public void run() t7^D-l  
{ KTv4< c]  
//获得文件长度 s#P:6]Ar  
//分割文件 sUc
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//实例FileSplitterFetch _Wma\(3$  
//启动FileSplitterFetch线程  +>#e=nH  
//等待子线程返回 M5O'=\+,F  
try{ $eX*  
if(bFirst) s5AgsMq  
{ iC*U$+JG  
nFileLength = getFileSize(); q~h:<,5  
if(nFileLength == -1) Mpm#GdT  
{ ^*>n4U  
System.err.println("File Length is not known!"); .eY`Ri<3t  
} I4~^TrznRa  
else if(nFileLength == -2) }e2F{pQ  
{ zt?H~0$LB  
System.err.println("File is not access!"); #HG&[Ywi  
} DqlK.  
else [pR)@$"k'  
{ "teyi"U+  
for(int i=0;i<nStartPos.length;i++) 
X+at%L=  
{ o(Kcs-W2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9-93aC.|}  
} Ux_<d?p  
for(int i=0;i<nEndPos.length-1;i++) GX5W^//}  
{ xYwkFB$$*  
nEndPos = nStartPos[i+1]; `xIh\q  
} OZT^\Ky_l  
nEndPos[nEndPos.length-1] = nFileLength; S&01SX6  
} `Cg^in\  
} @yKZRwg  
rS,j;8D-  
~p.%.b;~t  
//启动子线程 p8>R#9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (:OHyeNt  
for(int i=0;i<nStartPos.length;i++) N&x:K+Zm.  
{ qiU5{}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VA2<r(y~(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,CKvTxz0  
nStartPos,nEndPos,i); c'rd$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kwF]TO S  
fileSplitterFetch.start(); yQwVQUW8B  
} waQtr,m)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PkJcd->  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?l9=$'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lY,/W  
nEndPos = " + nFileLength); T.2ZBG~|[  
// fileSplitterFetch[nPos.length-1].start(); SSQ
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i@6wO?Tv  
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//等待子线程结束 >%h7dC3h  
//int count = 0; n^Vxi;F  
//是否结束while循环 ym
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boolean breakWhile = false; I.9o`Q[8&  
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while(!bStop) bg1un@%!l  
{ $m8leuo)  
write_nPos(); nuxd S,  
Utility.sleep(500); i6PE6> 1/  
breakWhile = true; j6og3.H-  
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A8!Ed$@  
for(int i=0;i<nStartPos.length;i++) H pFb{  
{  0Ve%.k  
if(!fileSplitterFetch.bDownOver) %YCd%lAe,  
{ VF=Z`  
breakWhile = false; CO'a
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break; f?0D%pxc}&  
} 17i$8  
} /x/4NeD  
if(breakWhile) ((cb4IX  
break; 6Hn)pD#U  
m#MlH=-  
P}l#VJWp  
//count++; _uJV
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//if(count>4)
6V P)$h8  
// siteStop(); ZOn_dYjC  
} phS>T  
3SFg#  
@?d?e+B  
System.err.println("文件下载结束！"); LfllO  
} (Y)!"_|  
catch(Exception e){e.printStackTrace ();} xx0k$Dqt2I  
} |!xpYT:  
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Rn;VP:HM  
//获得文件长度 ]?# #))RUS  
public long getFileSize() RJ*F>2  
{ f@x_#ov  
int nFileLength = -1; \n;g2/VjO  
try{ :ol6%Z's  
URL url = new URL(siteInfoBean.getSSiteURL()); )Oe`s(O@[I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y7La_FPrl  
httpConnection.setRequestProperty("User-Agent","NetFox"); Wxs>osq  
bKByU{t  
ArL-rJ{}  
int responseCode=httpConnection.getResponseCode(); V4EM5 Z\k  
if(responseCode>=400) E\iJP^n  
{ A!4VjE>  
processErrorCode(responseCode); 5A,=vE  
return -2; //-2 represent access is error /.2qWQH  
} 9fMSAB+c%  
_ .!aBy%xf  
.<dOED{v  
String sHeader; z{' 6f@]  
'+6<U[ L  
-nGwuEngP  
for(int i=1;;i++) p;e$kg1  
{ Ph Ttx(!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cyHU\!Z*Zq  
//Utility.log(in.readLine()); X\mz+al>[  
sHeader=httpConnection.getHeaderFieldKey(i); {=6)SBjf  
if(sHeader!=null) x,f>X;
04  
{ Mlwdha0  
if(sHeader.equals("Content-Length")) -)6;0  
{ "8?TSm8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h
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break; }U i_ynZ!  
} ,m:6qdN  
} vs\|rLa  
else jOv~!7T  
break; H@4/#V|Uy  
} [n!x&f8Xh  
} m\?\6Wk  
catch(IOException e){e.printStackTrace ();} E9L!)D]Y  
catch(Exception e){e.printStackTrace ();} !h*B (,  
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qy6K,/&3  
Utility.log(nFileLength); L W?&a3e  
{?y<%@  
~hzEKvs  
return nFileLength; )\"I*Jwir  
} q^%5HeV 2  
]xYayN!n  
X+%u(>>  
//保存下载信息（文件指针位置） s_v}=C^  
private void write_nPos() @'Q%Jc(  
{ e lay =%)  
try{ A-;^~I  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^F&A6{9f/h  
output.writeInt(nStartPos.length); d9|T
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for(int i=0;i<nStartPos.length;i++) ve~C`2=;  
{ 8lpzSJP4k  
// output.writeLong(nPos);  qJURPK  
output.writeLong(fileSplitterFetch.nStartPos); ^H-QYuz:T0  
output.writeLong(fileSplitterFetch.nEndPos); Qj:{p5H'  
} .X^43 q  
output.close(); ]Cr]Pvab{  
} %pqL-G  
catch(IOException e){e.printStackTrace ();} /xJY7yF  
catch(Exception e){e.printStackTrace ();} pKnIQa[c  
} l:x_j\  
| 4 `.#4  
<0>[c<{V<  
//读取保存的下载信息（文件指针位置） UFL0K  
private void read_nPos() c<>y!^g  
{ ~n8F7  
try{ RRNH0-D1l  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cT I,1U  
int nCount = input.readInt(); @| P3  
nStartPos = new long[nCount]; P.!;Uf}32  
nEndPos = new long[nCount]; {)@ j77P  
for(int i=0;i<nStartPos.length;i++) T*8_FR<  
{  J(^ >?d'  
nStartPos = input.readLong(); 69rwX"^  
nEndPos = input.readLong(); D*qzNT@`LR  
} v23TL
  
input.close(); 7pd$?=__I  
} {aT92-D3  
catch(IOException e){e.printStackTrace ();} jKYm/}d  
catch(Exception e){e.printStackTrace ();} -h=c=P  
} ?f9$OLEB  
s 8Jj6V  
%Dl_}  
private void processErrorCode(int nErrorCode) ti+pUlVrM  
{ wD}EW  
System.err.println("Error Code : " + nErrorCode); _m" ^lo  
} 4sI3(z)9H  
z}D#WWSxf  
@|Z*f\  
//停止文件下载 L+uOBW_  
public void siteStop() -GK'V  
{ 5vYsA1Z
 
bStop = true; S7Qen6lm  
for(int i=0;i<nStartPos.length;i++) 6OMb`A@/2  
fileSplitterFetch.splitterStop(); /m;O;2"  
#.~.UHt  
/O+e#z2f<  
} [q w  
} juR  
//负责部分文件的抓取 jzT;,4poy  
**FileSplitterFetch.java K7+^Yv\YQx  
*/ "i}Z(_7yr  
package NetFox; t ]71  
[9w, WJL  
jt/l,=9YK  
import java.io.*; j\nE8WH  
import java.net.*; Pb*q;9  
V2lp7"  
UP5%C;  
public class FileSplitterFetch extends Thread { ^GrNfB[Qu  
m)(SG  
Lc
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String sURL; //File URL 3LT+9ad2d  
long nStartPos; //File Snippet Start Position G#^m<G
^M  
long nEndPos; //File Snippet End Position anpJAB:1  
int nThreadID; //Thread's ID 7=L:m7T  
boolean bDownOver = false; //Downing is over )H.ubM1  
boolean bStop = false; //Stop identical EUJ1RhajF  
FileAccessI fileAccessI = null; //File Access interface .QNjeMu.  
}k4`  
,>:XE@xcp  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (/To?`  
{ wVlSjk  
this.sURL = sURL; fMgcK$  
this.nStartPos = nStart; =%:JjgKc*t  
this.nEndPos = nEnd; t%0r"bTi
 
nThreadID = id; k\Yu5)  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ](]*]a4ss  
} InAU\! ew  
yp( ?1  
b/T20F{W\o  
public void run() D>psh-,1  
{ V< 2IIH5^  
while(nStartPos < nEndPos && !bStop) cr2{sGn|  
{ )i},@T8[  
07~pf}  
!pG+Ak?  
try{ 2O}s*C$Xav  
URL url = new URL(sURL); v+|@}9|Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |`N$>9qN  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?
v0A/68s#  
String sProperty = "bytes="+nStartPos+"-"; %ZJ),9+  
httpConnection.setRequestProperty("RANGE",sProperty); ';i"?D?NAk  
Utility.log(sProperty); \=HfO?$ Ro  
FSI]k:  
^yzo!`)fso  
InputStream input = httpConnection.getInputStream(); a*pXrp@  
//logResponseHead(httpConnection); 0+$hkd n  
5q0BG!A%T  
xc:`}4  
byte[] b = new byte[1024]; olUqBQ&ol  
int nRead; #fJ/KY
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) uzat."`d'  
{ 'YBLU)v[  
nStartPos += fileAccessI.write(b,0,nRead); Lf$Q %eM0  
//if(nThreadID == 1) <=B1"'\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IMl9\U  
} '8]
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&!H~bzg  
g
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Utility.log("Thread " + nThreadID + " is over!"); f\U?:83  
bDownOver = true; ^bZ<9}  
//nPos = fileAccessI.write (b,0,nRead); k~'?"'  
} l}U~I 3}).  
catch(Exception e){e.printStackTrace ();} z7NGpA(  
} FZeN,  
} LAu+{'O\  
0KWy?6 X  
~v{C6)  
//打印回应的头信息 ?qq!%4mTB  
public void logResponseHead(HttpURLConnection con) gxBl1  
{ [Gh%nsH  
for(int i=1;;i++) B^Rw?:hN  
{ $1Q3Y'Q9  
String header=con.getHeaderFieldKey(i); F&nMI:h7  
if(header!=null) ~Q.8 U3"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /j=DC9_  
Utility.log(header+" : "+con.getHeaderField(header)); ,}xpYq_/  
else Vq)|gF[6i  
break; #`YxoY`  
} z=- 8iks|  
} [[.&,6  
-KJ}.q>upq  
U|y;b+n`  
public void splitterStop() 3:02`;3  
{ 6T} CPDRq  
bStop = true; 9.MGH2^L?  
} Y_|K,T6Zj@  
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A~yw8v5UF  
} ?%8})^Dd>4  
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/* [Ls2k&)0  
**FileAccess.java g0;&/;"  
*//文件访问(定位，写) `E4!u=%  
package NetFox; g:uaI  
import java.io.*; ctwhfS|Y0  
+ !E{L  
F$sF
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public class FileAccessI implements Serializable{ I;kUG_c(4  
P?3YHa^up  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V5(tf'  
RandomAccessFile oSavedFile; OyG_thX  
long nPos; 7E\K!v_  
jl 30\M7  
sJjl)Qs)T  
public FileAccessI() throws IOException ECE{xoc  
{ mPw56>  
this("",0); 6qHvq A
,  
} "0!eb3n  
l/y Kc8^<  
4%#V^??E  
public FileAccessI(String sName,long nPos) throws IOException 9$4/frd  
{ qMW%$L\HA  
oSavedFile = new RandomAccessFile(sName,"rw"); hVt+%tmNy  
this.nPos = nPos; aQym= 6%e  
oSavedFile.seek(nPos); ;nAg4ll8Q  
} (x@i,Ba@  
QB.*R?A  
;'WzfJ!q  
public synchronized int write(byte[] b,int nStart,int nLen) -Uhl9 =  
{ q!9v}R3(  
int n = -1; v|,[5IY  
try{ "k_n+cH%  
oSavedFile.write(b,nStart,nLen); ^S;RX*  
n = nLen; 0[$Mo3c+'  
} rz%[o,s  
catch(IOException e) A aF5`  
{ kgbr+Yw2X  
e.printStackTrace (); >1)@n3.<O  
} 1X!f!0=g+  
y u
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"DcueU#!  
return n; < 4EB|@E  
} *F%ol;|Q  
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} ]cGz~TN~  
j O5:{%  
ym,Ot1  
/* `Hp.%G(  
**SiteInfoBean.java l)!woOt  
*/ #&`WMLl+8  
package NetFox; &Ow?Hd0  
^1FZ`2u;  
;P0Y6v3  
public class SiteInfoBean { ?/|@ #&  
)(|0Ka
rF  
/NN[gz  
private String sSiteURL; //Site's URL ,h(f\h(9  
private String sFilePath; //Saved File's Path JXy
667_  
private String sFileName; //Saved File's Name /K<GN7vN  
private int nSplitter; //Count of Splited Downloading File gkq RO19  
ptcH>wM!  
Rp%\`'+Xz  
public SiteInfoBean() C4SD  
{//nSplitter的缺省值为5 as\K(c9  
//default value of nSplitter is 5 J ]l@ r  
this("","","",5); 51;%\@=  
}  [k&s!Qp  
rEpKX  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) V.a]IkK'K  
{ 4Z T  
sSiteURL= sURL; '14l )1g
.  
sFilePath = sPath; Gp3t?7S{T  
sFileName = sName; 4k
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this.nSplitter = nSpiltter; e#e
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^N}~U5  
<+1w'-  
} 4uAb LSh9  
m$y$wo<K[7  
!L.z4n,n+  
public String getSSiteURL() H1ui#5n2  
{ d# ?*62  
return sSiteURL; /wRK[i  
} ;KZ2L~ THG  
kc(b;EA  
-mYI[AG)  
public void setSSiteURL(String value) |u@>[*k'=  
{ o-i.'L)X  
sSiteURL = value; %?G.lej,x  
} s8I77._s  
YrcC"  
=z/mI y<  
public String getSFilePath() sbiDnRf  
{ rJ~(Xu>,s  
return sFilePath; Fe2
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} d?qO`- ~$  
$Qc%9p @i  
)Jjw}}$}Y  
public void setSFilePath(String value) pS)X\Xyw  
{ )mZy>45  
sFilePath = value; 3z. >b  
} bDh(;%=  
l0bT_?LhK  
cXEy>U|/  
public String getSFileName() (L  
{ DmpJzHj|  
return sFileName; ]8cX#N,M  
} +CHO0n  
c94PWPU  
cFNtY~(b  
public void setSFileName(String value) NU\t3JaR  
{ (8X8<>w~  
sFileName = value; T-cVM>u\D  
}  D)eKq!_  
>0okb3+  
~#x!N=q  
public int getNSplitter() (C[S?@S  
{ ,&l*AB!  
return nSplitter; lVBy&f  
} rTiuQdvo  
J#;m)5[ a%  
<6@NgSFz'  
public void setNSplitter(int nCount) Oua/NF)  
{ O9IjU10:  
nSplitter = nCount; MZF ;k$R  
} \z
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} O6 J<Lqgh  
(c7{dYV  
VrL>0d&d  
/* g/Nj|:3  
**Utility.java p2?+[d  
*/ /r{5Lyk*  
package NetFox; U"G+su->e  
o;P;=<  
t`3T_t Y  
public class Utility { qO'5*d;!d  
~$obcW1  
-Af`AX  
public Utility() ] ]-0RJ=S?  
{ _C#()#  
H~K2`Cr)4  
MX_a]$\:n  
} l;FgX+)  
R20
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//线程睡眠 KD*4n'm!>  
public static void sleep(int nSecond) r?>Hg+  
{ @g2L=XF  
try{ }u)GERWO  
Thread.sleep(nSecond); *\+'tFT6  
} #gT^hl5/  
catch(Exception e) %),O9*[9  
{ pjn%CR`;  
e.printStackTrace (); Mo=-P2)>lt  
}
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} B{KD ]  
fYPU'"hzG  
//日志 4hz,F/ I  
public static void log(String sMsg) ?
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{ p=T\3_q  
System.err.println(sMsg); c$z_Zi!g#  
} @_nhA/rlc  
"Jd1&FsCwX  
2DQC)Pe+z  
public static void log(int sMsg) ![n`n(oN  
{ FaM~ 56Pa  
System.err.println(sMsg); mMWNUkDq  
}  ]bSt[  
} e5]0<s$  
7FFYSv,[:  
}7v2GfE
kM  
/* aE$p;I  
**TestMethod.java a5&
j=3)|  
*/ g>oLc6T  
package NetFox; =h!m/f^x  
oOz6Er[KO  
[uHI 6Q#  
public class TestMethod { 5q>u }J  
zvj >KF|y  
Vs{sB*:
 
public TestMethod() FX 3[U+  
{ ///xx/weblogic60b2_win.exe 9q{dRS[A  
try{ |7fBiVo  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5xKR ]u  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Yl=  |P`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sl 5wX  
fileFetch.start(); +w5?{J  
} 2>s;xZ@/'R  
catch(Exception e){e.printStackTrace ();} ugP R)tDfM  
4 XQ?By  
U7=Z.*/62  
} _Pal)re]U  
y_#wR/E)u{  
=
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public static void main(String[] args) (*]Y<ve  
{ hn.fX:}  
new TestMethod(); mqw.v$>  
} aQ. \!&U  
} ^"-2fJ  
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