http断点续传简单实现（java)

/* y(h"0A1lW  
**SiteFileFetch.java 0>)F+QC  
*/ 2}jC%jR2  
package NetFox; xI(Y}>  
import java.io.*; Yo;Mexo!  
import java.net.*; l~c# X3E  
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public class SiteFileFetch extends Thread { ERZWK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean `;\~$^sj}  
long[] nStartPos; //开始位置 E (bx/f  
long[] nEndPos; //结束位置 VSW"/{Lp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 DfV'1s4y  
long nFileLength; //文件长度 >{@:p`*  
boolean bFirst = true; //是否第一次取文件 {u{8QKeC  
boolean bStop = false; //停止标志 jz"-E  
File tmpFile; //文件下载的临时信息 `d6,]'  
DataOutputStream output; //输出到文件的输出流 .:V4>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6BIr{SY  
public SiteFileFetch(SiteInfoBean bean) throws IOException
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{ fNaboNj[  
siteInfoBean = bean; E{W(5.kb;i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]?A-D,!(  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F uJ=]T  
if(tmpFile.exists ()) SJXP}JB_  
{ Mv#\+|p 1x  
bFirst = false; tX 3y{W10"  
read_nPos(); A&/VO$Y9wp  
} IBSoAL  
else mj_V6`m4  
{ 6V^KOG  
nStartPos = new long[bean.getNSplitter()]; oES4X{,  
nEndPos = new long[bean.getNSplitter()]; ST7Xgma-  
} z;+LU6V  
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} F`U YgN  
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public void run() %;qDhAu0  
{ f$p7L.d<  
//获得文件长度 T$r?LIa ,Q  
//分割文件 qbu5aK}+  
//实例FileSplitterFetch `R{ ZED l'  
//启动FileSplitterFetch线程 7$jO3J  
//等待子线程返回 ):pFI/iC  
try{ V07? sc<  
if(bFirst) 1H]E:Bq  
{ B#Z-kFn@  
nFileLength = getFileSize(); ]n$&|@  
if(nFileLength == -1) 9_I#{?  
{ <N}*|z7=b  
System.err.println("File Length is not known!"); ![CF >:e  
} ! tPHT  
else if(nFileLength == -2) o dTg.m  
{ gt{$G|bi  
System.err.println("File is not access!"); 'W]oQLD^R  
} |{JJ2c\W  
else Qb~&a1&s#  
{ ?QfomTT  
for(int i=0;i<nStartPos.length;i++) !|`vW{
v  
{ ;OD+6@Sr  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); SF?s^  
} 3&ES?
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for(int i=0;i<nEndPos.length-1;i++) IQA<xqX   
{ ;$>wuc'L  
nEndPos = nStartPos[i+1]; ;_<K>r*  
} gP 6`q  
nEndPos[nEndPos.length-1] = nFileLength; c0M>CaKD  
} J0a#QvX!  
} "Ir.1FN  
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g1zX^^nd,V  
//启动子线程 "}'Sk(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Q]NGd 0J  
for(int i=0;i<nStartPos.length;i++) ^tY$pPA  
{ 96.Vm*/7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5*31nMP\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), cAAyyc"yJ  
nStartPos,nEndPos,i); wc6v:,&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qc6eqE  
fileSplitterFetch.start(); EU@XLm6  
} 2W]y9)<c  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q1(6U6L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Vuu_Sd  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5xF R7%_&  
nEndPos = " + nFileLength); 'YUx&FcM  
// fileSplitterFetch[nPos.length-1].start(); sM8AORd  
vhaUV#V"  
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//等待子线程结束 }2-p=Y:6  
//int count = 0; *UlL\  
//是否结束while循环 VG+WVk  
boolean breakWhile = false; >W[#-jA_Z  
sB>ZN3ptH^  
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while(!bStop) ,H+LE$=  
{ &}/h[v_#'  
write_nPos(); oy!Dm4F  
Utility.sleep(500); %/(>>*}Kw|  
breakWhile = true; \r+8}8  
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for(int i=0;i<nStartPos.length;i++) sBfPhBT|  
{ en6oFPG  
if(!fileSplitterFetch.bDownOver)  L4,Ke  
{ /n|`a1!  
breakWhile = false; F9&ae*>,  
break; ={a_?l%  
} m;]glAtt  
} ,J0BG0jB^u  
if(breakWhile) wRi` L7  
break; j/9Uf|z-_  
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:x<'>)6  
//count++; kW=GFj)L  
//if(count>4) r+WY7'c  
// siteStop(); >S:>_&I`I  
} CN"hx-f  
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<%  
System.err.println("文件下载结束！"); h&4f9HhS=  
} -n`igC  
catch(Exception e){e.printStackTrace ();} HRY?[+  
} CL-mt5Kx#7  
{,aI0bw;  
7>`VZ?  
//获得文件长度 g, %xGQ4+  
public long getFileSize() HX3R@^vo  
{ <Y9xHn&  
int nFileLength = -1; Uc3-n`C  
try{ URFp3qE  
URL url = new URL(siteInfoBean.getSSiteURL()); =NHzh!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =(~UK9`  
httpConnection.setRequestProperty("User-Agent","NetFox"); h^D]@H  
-^sbf.  
9(/ ;Wutj"  
int responseCode=httpConnection.getResponseCode(); Z$? Ql@M  
if(responseCode>=400) YIQm;EEG  
{ 8,,$C7"EP  
processErrorCode(responseCode); 9O+><x[i  
return -2; //-2 represent access is error 7.o:(P1??g  
} R]7-6  
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String sHeader; ]OZk+DU:  
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for(int i=1;;i++) BF_R8H,<%  
{ RG)!v6
  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @KhDQ0v]5  
//Utility.log(in.readLine()); aJC,  
sHeader=httpConnection.getHeaderFieldKey(i); +hIS
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if(sHeader!=null) }!i#1uHUH:  
{ w<hw>e^.  
if(sHeader.equals("Content-Length")) KKd Sh1  
{ )-_]y|/D:r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); OeuM9c{  
break; WUM&Lq k"  
} %U&O \GB  
} {/C \GxH+  
else 5xm^[o2#y  
break; }T?0/N3y&  
} V #0F2GV<,  
} pb(YA/  
catch(IOException e){e.printStackTrace ();} 3U<\s=1?X  
catch(Exception e){e.printStackTrace ();} &;%z1b>F  
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Utility.log(nFileLength); 1XAXokxj  
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return nFileLength; =7JvS~s  
} s0 ZF+6f  
J2$L[d^  
+P?!yH,n  
//保存下载信息（文件指针位置） >[=fbL@N<@  
private void write_nPos() ^ 2"r't  
{ nVF?.c  
try{ Dk!;s8}*c  
output = new DataOutputStream(new FileOutputStream(tmpFile)); JM-spi o  
output.writeInt(nStartPos.length); cY|?iEVs)  
for(int i=0;i<nStartPos.length;i++) R&cOhUj22J  
{ 37hs/=x  
// output.writeLong(nPos); R#ABda9  
output.writeLong(fileSplitterFetch.nStartPos); i(
^&ZmG  
output.writeLong(fileSplitterFetch.nEndPos); B&~#.<23:  
} gAA2S5th  
output.close(); W0X/&v,k*  
} (j^Qa~{mG4  
catch(IOException e){e.printStackTrace ();} sw.cw}1  
catch(Exception e){e.printStackTrace ();} L> ehL(]!  
} uES|jU{]b  
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//读取保存的下载信息（文件指针位置） @)A)cBv#  
private void read_nPos() 42a.@JbLQ  
{
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try{ M]O _L  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "K3"s Ec%  
int nCount = input.readInt(); @l)HX'z0d  
nStartPos = new long[nCount]; 2D;,
'  
nEndPos = new long[nCount]; w-%V9]J1  
for(int i=0;i<nStartPos.length;i++) $4^cbk  
{ =IQ+9Fl2  
nStartPos = input.readLong(); q6h'=By  
nEndPos = input.readLong(); ~c&ygL3  
} 3;@/`Z_\lt  
input.close(); 'OIOl  
} S+^*rw
  
catch(IOException e){e.printStackTrace ();} %#xdD2oN  
catch(Exception e){e.printStackTrace ();} {sn RS)
-  
} Z)?i&y?  
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private void processErrorCode(int nErrorCode) Zl5cHejM  
{ dzIcX*"  
System.err.println("Error Code : " + nErrorCode); _MF:?p,l  
} 3*< O-
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s}8(__|  
//停止文件下载 /5qeNjI+2  
public void siteStop() !~+"TI}_%w  
{ 'R&Y pR  
bStop = true; X]^FHYjhS  
for(int i=0;i<nStartPos.length;i++) BI\ )vr$  
fileSplitterFetch.splitterStop(); ]JQ7x[  
{BkTJQ)  
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} {}r#s>  
} : GVyY]qBU  
//负责部分文件的抓取 0E*q-$P  
**FileSplitterFetch.java q]%eLfC(  
*/ Wpgp YcPS  
package NetFox; 0(!j]w"r3  
~#z8Q{!O  
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import java.io.*; Af~>}-`a  
import java.net.*; ObK-<kGcB  
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public class FileSplitterFetch extends Thread { vL>cYbJ<  
_[D6WY+  
*C/bf)w  
String sURL; //File URL ,t"?~Hl".  
long nStartPos; //File Snippet Start Position =<,>dBs}\  
long nEndPos; //File Snippet End Position ^HJvT)e4  
int nThreadID; //Thread's ID p:*)rE  
boolean bDownOver = false; //Downing is over v:2*<;  
boolean bStop = false; //Stop identical DhN{Y8'~  
FileAccessI fileAccessI = null; //File Access interface s(~tL-_ K  
xF:}a:c@H  
=ttvC"4?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException G~z=,72  
{ K90wX1&  
this.sURL = sURL; PxuE(n V[  
this.nStartPos = nStart; 5k%GjT  
this.nEndPos = nEnd; D8Ntzsr6  
nThreadID = id; Ll" Kxg  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >XTDN  
} ,\YlDcl':0  
<+7]EwVcn^  
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public void run() qDG{hvl[1r  
{ Pu|PIdu!08  
while(nStartPos < nEndPos && !bStop) (R'GrN>  
{ mEL<d,XhI  
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try{ d-GU164  
URL url = new URL(sURL); $&fP%p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7D5[ L  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;kW+  
String sProperty = "bytes="+nStartPos+"-"; f*Z8C9)  
httpConnection.setRequestProperty("RANGE",sProperty); OTgctw1s  
Utility.log(sProperty); cSbyVC[r  
HPGIz!o  
V/p+Xv(Zt  
InputStream input = httpConnection.getInputStream(); c(@(j8@S  
//logResponseHead(httpConnection); _wp>AJ r  
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}PC_qQF  
byte[] b = new byte[1024]; a ~  
int nRead; !?AgAsSmc  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) U?@ s`.  
{ FfeX;pi  
nStartPos += fileAccessI.write(b,0,nRead); D8OW|wVE  
//if(nThreadID == 1) 71S~*"O0f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <0EVq8h  
} *5e"suS2  
~__r-z  
cDkq@H:  
Utility.log("Thread " + nThreadID + " is over!"); <\44%M"iC-  
bDownOver = true; V(lxkEu/Fj  
//nPos = fileAccessI.write (b,0,nRead); 3^jkd)xw  
} [9<c;&$LU  
catch(Exception e){e.printStackTrace ();} JWh5gOXd  
} +#;t.&\80N  
} ^ gy"$F3{`  
be<7Vy]j  
hFW{qWP  
//打印回应的头信息 J!\Cs1!f  
public void logResponseHead(HttpURLConnection con) ]'.D@vFGO  
{ 4](jV}Hg  
for(int i=1;;i++) =&_Y=>rA]0  
{ A$JL"~R  
String header=con.getHeaderFieldKey(i); .RazjXAY  
if(header!=null) j7
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); EPd9'9S  
Utility.log(header+" : "+con.getHeaderField(header)); )ajF ca@v  
else h!~Qyb>W  
break; v=pkze  
} bZ5cKQ\6  
} 6E^h#Ozl 9  
 BN_I#8r  
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public void splitterStop() KbXENz&C  
{ 4MFdhJoN  
bStop = true; IPVD^a?  
} 3+<f7  
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cv=H6j]h|  
} 6

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/* 1B0+dxN`  
**FileAccess.java ["u:_2!4P  
*//文件访问(定位，写) j}`XF?2D  
package NetFox; VYo2m  
import java.io.*; +|w%}/N  
m=4hi(g  
LykB2]T  
public class FileAccessI implements Serializable{ >)j`Q1Qc\  
rOo|.4w  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 up;^,I
  
RandomAccessFile oSavedFile; 0en Bq>vr  
long nPos; _xmS$z)TO  
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=C(((T.  
public FileAccessI() throws IOException g7l?/p[n  
{ /8O;Q~a  
this("",0); U
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} Zk+c9,q  
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public FileAccessI(String sName,long nPos) throws IOException q; ?Kmk  
{ 9
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oSavedFile = new RandomAccessFile(sName,"rw"); l+r3|b  
this.nPos = nPos; ;CtTdr  
oSavedFile.seek(nPos); r.ib"W#4  
} U)JwoO  
H/^t]bg,  
sK/Z'h{|  
public synchronized int write(byte[] b,int nStart,int nLen) /D>G4PP<  
{ n8.Tag(#  
int n = -1; K/l*Saj  
try{ >Tp`Kri  
oSavedFile.write(b,nStart,nLen); 2[X\*"MQ2  
n = nLen; G_E \p%L>]  
} "nA~/t=  
catch(IOException e) kQ99{lH,5  
{ &
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e.printStackTrace (); cna/?V  
} 8#ZF<BY  
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2{9%E6%#  
return n; 2]V&]s8Wi=  
} DyC
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>
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} 0..]c-V(G  
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/* .FeVbZW  
**SiteInfoBean.java 2hf7F";Af  
*/ O gtrp)x9  
package NetFox; j2`%sBo  
/4YxB,  
H{,qw%.|KA  
public class SiteInfoBean { ^US
ol/  
>*h3u7t  
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private String sSiteURL; //Site's URL %
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private String sFilePath; //Saved File's Path pC/13|I  
private String sFileName; //Saved File's Name aXgngwq  
private int nSplitter; //Count of Splited Downloading File 7U2?in}?Qi  
/_!Ed]  
+lhnc{;WJv  
public SiteInfoBean() /
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{//nSplitter的缺省值为5 U.pGp]\Q)G  
//default value of nSplitter is 5 >zV  
this("","","",5);
ly::?  
} 6=p!`DOd  
h'"~t#r  
hH~GH'dnaE  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2v`Q;%7O  
{ I\<)9`O  
sSiteURL= sURL; $6~t|[7:%Y  
sFilePath = sPath; P{2j31u`  
sFileName = sName; hiw>Q7W  
this.nSplitter = nSpiltter; |lMc6C  
B4eV$~<  
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} @y/!`Ziw  
'B;n&tJ   
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public String getSSiteURL() YM&i  
{ 9dwLkr  
return sSiteURL; jk{m8YP)E  
} ddwokXx (  
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public void setSSiteURL(String value) Ns$,.D  
{ v<vaPvW  
sSiteURL = value; Xu7lV  
} ]Q -.Y-J/O  
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ttY[\D&ZS  
public String getSFilePath() 9dFo_a*?  
{ 3|(3jIa  
return sFilePath;
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} d0 mfqP=  
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public void setSFilePath(String value) ot,=.%O  
{ Qov*xRO6  
sFilePath = value; 4k)0OQeW6  
} %(B6eiA  
;umbld0  
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public String getSFileName() $msf~M*  
{ br')%f}m  
return sFileName; rih@(;)1  
} ?nwg.
&P  
qT^0 %O:  
"4L_BJZ  
public void setSFileName(String value) &#;lmYyaui  
{ wPvYnhr|G-  
sFileName = value; `S|T&|ad0  
} xTy)qN]P  
`8kL=%(h  
W?gelu]  
public int getNSplitter() lz4M)pL^  
{ @c=bH>Oz  
return nSplitter; Yb?(Q%  
} bd&Nf2  
H^JFPvEc  
KeWIC,kq  
public void setNSplitter(int nCount) Ee^>Q*wahw  
{ zYEb#*Kar  
nSplitter = nCount; <f;Xs(  
} y'_2|5!Qs  
} 0Vj!'=Ntv  
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w|:
ev_c|  
/* #kp+e)F  
**Utility.java o`.5NUn  
*/ %$F_oO7"  
package NetFox; `!C5"i8+i2  
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public class Utility { 6SEq 2  
!H(V%B
%  
F6Qnz8|  
public Utility() :Fi$-g  
{ %t%D|cf  
`.F3&pA  
> QK"r7f/  
} ?&bB?mg\  
<[V1z=Eo/]  
//线程睡眠 Ph17(APt,Q  
public static void sleep(int nSecond) CK8!7=>}^  
{ @O8X )  
try{ V eLGxc  
Thread.sleep(nSecond); iZ9ed]mf  
} ]JlM/  
catch(Exception e) ldr~=<hsZ  
{ AdWP  
e.printStackTrace (); Is>~P*2Y=  
} U,V+qnS  
} *rmM2{6  
S'=}eeG  
//日志 ft?c&h;At  
public static void log(String sMsg) V"8w:?  
{ #,;Q|)AD:e  
System.err.println(sMsg); SA{5A 1  
} ddw^oU  
G=&nwSL  
b5W(}ka+  
public static void log(int sMsg) X{P=2h#g  
{ } ^WmCX2a  
System.err.println(sMsg); j"n"=rTTQ  
} T]2=  
} 0xc|Wn>  
pQk@ +r  
=gHUY&sPu8  
/* t>eeOWk3  
**TestMethod.java
Tb!jIe  
*/ Rg 5kFeS  
package NetFox; #pk  
@k\npFKQm  
U&gI_z[  
public class TestMethod { d8&T62Dnd4  
j5G=ZI86y  
[p_<`gU?  
public TestMethod() 2 @t?@,c  
{ ///xx/weblogic60b2_win.exe $J*lD-h-  
try{ @gk{wh>c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4oN*J +"=+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); RAFdo  
SiteFileFetch fileFetch = new SiteFileFetch(bean); c1Hp  
fileFetch.start(); 4}Yn!
"jW&  
} I[bWd{i:  
catch(Exception e){e.printStackTrace ();} af|x(:!H  
41I2t(H @z  
$8>II0C.  
} wS+j^ ;"  
[!U! Z'i  
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public static void main(String[] args) >`I%^+z  
{ HH|N~pBJB  
new TestMethod(); 5?8jj  
} o`{^ptu1q  
} apWv+A  
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