http断点续传简单实现（java)

/* E*&vy  
**SiteFileFetch.java 810|Tj*U%  
*/ c?Y*Y   
package NetFox; .N;=\C
*  
import java.io.*; @)F)S7  
import java.net.*; =>S]q71  
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`?H]h"{7Q  
public class SiteFileFetch extends Thread { :9afg  
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SiteInfoBean siteInfoBean = null; //文件信息Bean J`Q>3]wL  
long[] nStartPos; //开始位置 $GV7o{"&  
long[] nEndPos; //结束位置 HdI8f!X'TG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PN%zIkbo  
long nFileLength; //文件长度 ^
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boolean bFirst = true; //是否第一次取文件 Y>z>11yEB0  
boolean bStop = false; //停止标志 DPY}?dC  
File tmpFile; //文件下载的临时信息 YRk(u7:0  
DataOutputStream output; //输出到文件的输出流 D
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 
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public SiteFileFetch(SiteInfoBean bean) throws IOException >~rTqtKd  
{ O^PKn_OJ  
siteInfoBean = bean; G&SB-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3d8L6GJ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [Y/} ^  
if(tmpFile.exists ()) OF>mF~  
{ 2>9C-VL2  
bFirst = false; 1.JK33  
read_nPos(); .#!lP/.eQP  
} Y|m+dT6  
else j3oV+zZ49  
{ \&:nFb%=  
nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()]; h8j.(  
} RU{twL.B  
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} udH7}K v  
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public void run() o 11jca|  
{ Xq4O@V  
//获得文件长度 E =67e=h  
//分割文件 iXkF1r]i  
//实例FileSplitterFetch &AMl:@p9  
//启动FileSplitterFetch线程 ^6
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//等待子线程返回 Hvauyx5T  
try{ ^0)g/`H^>  
if(bFirst) G't$Qx,IC  
{ GKqm&/M*=  
nFileLength = getFileSize(); ;O5zUl-`  
if(nFileLength == -1) Ty\R=y}}  
{ ;C#F>SG\S  
System.err.println("File Length is not known!"); HWAdhDZ  
} ,pfG  
else if(nFileLength == -2) M^Yh|%M  
{ R{4^t97wH{  
System.err.println("File is not access!"); #Pau\|e_  
} uc{Ihw  
else g/_5unI}u  
{ 5~U/  
for(int i=0;i<nStartPos.length;i++) m 0C@G5  
{ X05/uX{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); h&iC;yj=  
} P5V}#;v  
for(int i=0;i<nEndPos.length-1;i++) \7eUw,~Q>  
{ K3&qq[8.e  
nEndPos = nStartPos[i+1]; c):/!Q  
} 539>WyG5  
nEndPos[nEndPos.length-1] = nFileLength; Paq4  
} ~Cttzn]pR  
} <}Vrl`?h  
7+cO_3AB  
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//启动子线程 l30EKoul)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Wi<m{.%\E  
for(int i=0;i<nStartPos.length;i++) =s{>Fsm1  
{ *Q
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >uB?rGcM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CW K7wZM  
nStartPos,nEndPos,i); uZYF(Yu  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iyE7V_O T  
fileSplitterFetch.start(); Q*cf
(  
} <=&`ZH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e"cXun4nS=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T{^rt3a  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]0OR_'?,  
nEndPos = " + nFileLength); bWS&Yk(  
// fileSplitterFetch[nPos.length-1].start(); J{<X7uB  
CxmKz78  
~P qM]^  
//等待子线程结束 E=Bf1/c\  
//int count = 0; Oszj$C(jF  
//是否结束while循环 :,7hWs
 
boolean breakWhile = false; ttQGo
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~=LE0.3[  
while(!bStop) A\DC
W  
{ S@tLCqV4  
write_nPos(); ^ +\dz  
Utility.sleep(500); #%2rP'He  
breakWhile = true; W*:.Gxv]  
6_;icpN]  
MchA{p&Ol  
for(int i=0;i<nStartPos.length;i++) {Mk6T1Bkq  
{ `(;m?<%  
if(!fileSplitterFetch.bDownOver) gVuFHHeUz  
{ n8[!pH~6  
breakWhile = false; E]d.z6k  
break; Q{>k1$fkV  
} T763
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} R29~~IOqO  
if(breakWhile) C): 1?@  
break; =svN#q5s  
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//count++; o/)h"i0P  
//if(count>4) JR|ck=tq  
// siteStop(); >y>5#[M!  
} HJH{n
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>:!5*E5?  
System.err.println("文件下载结束！"); /N.b%M]!  
} M_f:A  
catch(Exception e){e.printStackTrace ();} r5/0u(\LB  
} T>Z<]s  
0mVNQxHI  
\@zHON(  
//获得文件长度 hfTY.  
public long getFileSize() ?^{Ah}x  
{ Izc\V9+  
int nFileLength = -1; IOH}x4  
try{ kD%( _K5  
URL url = new URL(siteInfoBean.getSSiteURL()); }8z?t:|S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); } OR+Io  
httpConnection.setRequestProperty("User-Agent","NetFox"); j (d~aqW  
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\)[j_^  
int responseCode=httpConnection.getResponseCode(); & .j&0WE  
if(responseCode>=400) ?V=ZIGj  
{ JbbzV>  
processErrorCode(responseCode); EZGIf/ 3  
return -2; //-2 represent access is error pv&sO~!iC  
} eByz-,{P  
e*C(q~PQ  
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String sHeader; q;CiV  
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for(int i=1;;i++) J@'wf8Ub  
{ "S]TP$O D  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )&O %*@F  
//Utility.log(in.readLine()); 3 i0_hZ  
sHeader=httpConnection.getHeaderFieldKey(i); 'H!Uh]!  
if(sHeader!=null) BU_nh+dF  
{ am'7uy!ka~  
if(sHeader.equals("Content-Length")) x9g#<2w8  
{ X_h}J=33Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); cT,sh~
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break; {tZ.v@  
} fr3d  
} SnfYT)Ph  
else W!(zT6#  
break; AkV#J, 3LC  
} CC
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} Hn"RH1Zy  
catch(IOException e){e.printStackTrace ();} 9A=,E&  
catch(Exception e){e.printStackTrace ();} 4HlQ&2O%#  
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Utility.log(nFileLength); `^&OF uee  
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return nFileLength; KRzAy)8  
} Yq KCeg  
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~?BXti<!  
//保存下载信息（文件指针位置） ?tbrbkx  
private void write_nPos() 25?6gu*Z  
{ ICQKP1WFp  
try{ .q>iXE_c  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C'x&Py/#  
output.writeInt(nStartPos.length); :o3N;*o>)0  
for(int i=0;i<nStartPos.length;i++) l_p2Riv  
{ GTd,n=  
// output.writeLong(nPos); .k !{*  
output.writeLong(fileSplitterFetch.nStartPos); MTn{d  
output.writeLong(fileSplitterFetch.nEndPos); (<9u-HF#  
} ]=BB#  
output.close(); 4hj|cCrO  
} =^?/+p8k  
catch(IOException e){e.printStackTrace ();} Zy/_ E@C}u  
catch(Exception e){e.printStackTrace ();} hgq;`_;1,  
} @ 6vIap|  
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//读取保存的下载信息（文件指针位置） xJe%f\UDu  
private void read_nPos() PW0LG^xp`  
{ $UwCMPs X  
try{ ]f_p8?j"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bt?5*ETA  
int nCount = input.readInt(); ~xFkU#  
nStartPos = new long[nCount]; QXK{bxwC  
nEndPos = new long[nCount]; W=?<<dVYD  
for(int i=0;i<nStartPos.length;i++) N!}f}oF  
{ %N._w!N<5n  
nStartPos = input.readLong(); uY To9A  
nEndPos = input.readLong(); W>r+h-kR  
} J&_n9$  
input.close(); RA 6w}:sq7  
} 9(Xn>G'iT  
catch(IOException e){e.printStackTrace ();} SXh-A1t  
catch(Exception e){e.printStackTrace ();} wCBplaojJ  
} PKz':_|  
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private void processErrorCode(int nErrorCode) ~} ~4  
{ /;$[E  
System.err.println("Error Code : " + nErrorCode); !ohN!P7&  
} "AqB$^S9t  
tH4B:Bgj!  
$??I/6  
//停止文件下载 HPVEnVn  
public void siteStop() 2=}FBA,2  
{ x8|J-8A(  
bStop = true; Hl=xW/%6y  
for(int i=0;i<nStartPos.length;i++) 2\$
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fileSplitterFetch.splitterStop(); BgT*icd8d  
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} |-H&o]  
} Id9TG
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//负责部分文件的抓取 er\|i. Y  
**FileSplitterFetch.java L~3Pm%{@A  
*/ lB4WKn=?Kl  
package NetFox; 6S#Cl>v  
 Z\sDUJ  
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import java.io.*; M6TD"-  
import java.net.*; /-s6<e!  
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public class FileSplitterFetch extends Thread { 1Y,Z %d  
kx^/*~ex  
:4|4=mkr  
String sURL; //File URL !)$Zp\Sg  
long nStartPos; //File Snippet Start Position LP=)~K
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long nEndPos; //File Snippet End Position q^nVN#  
int nThreadID; //Thread's ID ;.C\Ss<>*  
boolean bDownOver = false; //Downing is over j8gdlIx  
boolean bStop = false; //Stop identical zuCSj~  
FileAccessI fileAccessI = null; //File Access interface K sCyFp  
:!QAC@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException V]^$S"Tv  
{ jEwIn1  
this.sURL = sURL; An@t?#4gxi  
this.nStartPos = nStart; ssL
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this.nEndPos = nEnd; xSu >  
nThreadID = id; ,r}6iFu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5V-I1B&  
} wIgS3K  
Bw.i}3UT6  
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public void run() -\MG}5?!  
{ FI.\%x  
while(nStartPos < nEndPos && !bStop) d(K+);!  
{ I^]nqK  
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6\t@)=C,Q  
try{ dN6?c'iN?2  
URL url = new URL(sURL); ~J]qP#C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qP ,E
BE  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7 8,n%=nG  
String sProperty = "bytes="+nStartPos+"-"; X3& Jb2c2  
httpConnection.setRequestProperty("RANGE",sProperty); ^J{:x  
Utility.log(sProperty); PY'2h4IL  
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InputStream input = httpConnection.getInputStream(); Y-9I3?ar  
//logResponseHead(httpConnection); c@Is2 9t*  
TqQ[_RKg2  
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byte[] b = new byte[1024]; OrW  
int nRead; I=#$8l.*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qgB_=Q#E  
{ @F>D+=hS  
nStartPos += fileAccessI.write(b,0,nRead); [>9is=>o.  
//if(nThreadID == 1) 9M ]_nPY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VN.Je:Ju  
} kGJC\{N5N  
O0:q;<>z  
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Utility.log("Thread " + nThreadID + " is over!"); QWU-m{@~&  
bDownOver = true; O&&~NXI\  
//nPos = fileAccessI.write (b,0,nRead); 3U}%2ARo_  
} HKeK<V  
catch(Exception e){e.printStackTrace ();} BLFdHB.$T  
} 8,|kao:  
} I 6O  

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//打印回应的头信息 1H9!5=Ff  
public void logResponseHead(HttpURLConnection con) d=^z`nt !R  
{ ~Gw*r\\+  
for(int i=1;;i++) 3XKf!P  
{ 1mJHued=6  
String header=con.getHeaderFieldKey(i); sRf
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if(header!=null) c",*h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); }2oc#0  
Utility.log(header+" : "+con.getHeaderField(header)); M\=2uKG#
 
else T{'RV0%   
break; 0\$2X- c  
} 1x^GWtRp  
} !m$jk2<  
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public void splitterStop() W3RT{\  
{ ]'S^]  
bStop = true; 6B-16  
} t,'<gI
 
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} (sj,[  
[-&Zl(9&  
>dT*rH3w  
/* kVL.PY\K  
**FileAccess.java 7z-[f'EIUI  
*//文件访问(定位，写) ^Dx&|UwiZa  
package NetFox; ;kK/_%gN-G  
import java.io.*; lfg6646?S  
+[P{&\d4}  
I:.s_8mH}  
public class FileAccessI implements Serializable{ M3AXe]<eC1  
Pc9H0\+Xk  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 zreU')a  
RandomAccessFile oSavedFile; iQ{VY ^ 0  
long nPos; /tLVX} &  
;rS{:  
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public FileAccessI() throws IOException Js;h%  
{ hOeRd#AQK  
this("",0); pJ{Y lS{  
} <vP=zk  
?#fQ~ s  
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public FileAccessI(String sName,long nPos) throws IOException 'PHl$f*k  
{ +h$ 9\  
oSavedFile = new RandomAccessFile(sName,"rw"); cnLro  
this.nPos = nPos;
3CJwj  
oSavedFile.seek(nPos); cNH7C"@GVu  
} _G0x3  
##{taR8  
DI%saw  
public synchronized int write(byte[] b,int nStart,int nLen) r/1(]#kOX  
{ [ 3HfQ  
int n = -1; ctUp=po  
try{ wS*E(IAl  
oSavedFile.write(b,nStart,nLen); Y ay?=Y{  
n = nLen; Mfs?x a  
} N;gfbh]  
catch(IOException e) ;\]@K6m/Ap  
{ *`U~?q}  
e.printStackTrace (); 0aAoV0fMDz  
} 2?x4vI np;  
H#&00Q[  
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return n; U~8g_*  
} `2snz1>!j  
u&NV,6Fj2[  
*](iS  
} 7Ix973^  
~m |BC*)  
nrb Ok4Dz  
/* M_8{]uo  
**SiteInfoBean.java {8OCXus3m  
*/ |^aKs#va  
package NetFox; ]{iQ21`a-  
#*}+J3/  
"}!G!k:  
public class SiteInfoBean { #`IN`m|  
MJvp6n  
Vc2`b3"Br  
private String sSiteURL; //Site's URL m2o0y++TjW  
private String sFilePath; //Saved File's Path ]tD]Wx%  
private String sFileName; //Saved File's Name SdWV3  
private int nSplitter; //Count of Splited Downloading File >/|*DI-HJ  
o@Oqm>]SS  
nlYNN/@"  
public SiteInfoBean() OCUr{Nh  
{//nSplitter的缺省值为5 &vJH$R  
//default value of nSplitter is 5 :>*7=q=  
this("","","",5); r,udO,Yi=c  
} J *yg&  
Ib`XT0k  
/\Ef%@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9UkBwS`  
{ E3i4=!Y  
sSiteURL= sURL; Zh,71Umz  
sFilePath = sPath; g ?k=^C  
sFileName = sName; IU[ [H#  
this.nSplitter = nSpiltter; #jk_5W  
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} NgwbQ7)  
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public String getSSiteURL() 25T18&R  
{ K;(mC<  
return sSiteURL; g{Rd=1SK]  
} ;r8X.>P*  
n ;Ei\\p!  
U17d>]ka  
public void setSSiteURL(String value) yr6V3],Tp  
{ "zc l|@  
sSiteURL = value; R=dC4;  
} O=lzT~G|4  
[}:$yg  
y(&Ac[foS}  
public String getSFilePath() =I4lL]>  
{ >Q/Dk7#  
return sFilePath; VQs5"K"  
} C}X\|J  
n?Q|)2 2  
.N3mb6#[R  
public void setSFilePath(String value) @,}UWU  
{ C+]I@Go'Tk  
sFilePath = value; -} +[  
} u!s2BC0}N  
~@!bsLSMU  
I|OoRq  
public String getSFileName() 92c HwWZ!  
{ T+$[eWk"a  
return sFileName; B[}6-2<>?C  
} )1z@
  
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@L`jk+Y0vF  
public void setSFileName(String value) >sF)BoLc  
{ cS$_\65  
sFileName = value; 0a7Ppntb@  
} 9!GM{  
.VqhV  
jylD6IT  
public int getNSplitter() ye97!nIg@  
{ RNL9>7xV  
return nSplitter; "|NI]
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} wq{hF<  
;|RTx  
Q
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public void setNSplitter(int nCount) [KQi.u  
{ Kq!3wb;  
nSplitter = nCount; }b}m3i1  
} yVfC-Z  
} vX>)je
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/* <%^&2UMg  
**Utility.java FwK]$4*  
*/ [ )F<V!  
package NetFox; N#]ypl  
@CoIaUVP  
lYIH/:T  
public class Utility { `XKLU
 
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public Utility() K:M8h{Ua  
{ =D(j)<9$A  
h(4v8ae  
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} h1RSVp+?n  
"4Nt\WQ  
//线程睡眠 +_!QSU,@  
public static void sleep(int nSecond) ~Ei<Z`3}7"  
{ h;Kx!5)y  
try{ TpaInXR  
Thread.sleep(nSecond); CITc2v3a  
} <aw[XFg  
catch(Exception e) !Cs_F&l"j  
{ qK+5NF|  
e.printStackTrace (); Sdo-nt  
} UG^q9 :t  
} mDWG7Asp  
i%/+5gq  
//日志 x;S @bY  
public static void log(String sMsg) cL]1f  
{ '"^'MXa  
System.err.println(sMsg); zA 3_Lx!  
} kM6 Qp  
NbobliC=  
|)&%A%m  
public static void log(int sMsg) GyIV Hby  
{ x2EUr,7  
System.err.println(sMsg); F [M,]?   
} }k0_5S  
} siaG'%@*r  
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PCvWS.{  
/* !if   
**TestMethod.java pmM9,6P4@  
*/ !1k_PY5)  
package NetFox; F2WKd1U  
W!X@  
|4JEU3\$  
public class TestMethod { 45e~6",  
sB</DS  
XSDpRo  
public TestMethod() :h$$J lP  
{ ///xx/weblogic60b2_win.exe _w{Qtj~s|  
try{ KXy6Eno  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $`c:&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j.Hf/vi`z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +0&/g&a\R  
fileFetch.start(); osRy e3  
} 2T35{Q!=F  
catch(Exception e){e.printStackTrace ();} eavV?\uV%  
1^}+=~  
g(052]  
} f 2.HF@  
\zkg  
@- xjfC\d  
public static void main(String[] args) ^y::jK  
{ G2D

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new TestMethod(); ,hVli/   
} x4 yR8n(  
} pb}*\/s  
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