http断点续传简单实现（java)

/* j[A(@w"  
**SiteFileFetch.java xxl|j$m  
*/ e/:?9  
package NetFox; Q Kr/  
import java.io.*; ^JMG'@x  
import java.net.*; |,oLZCNa  
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public class SiteFileFetch extends Thread { X-<,zRM  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w5PscEc  
long[] nStartPos; //开始位置 %(khE-SW  
long[] nEndPos; //结束位置 fw,,cu`YA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m{RXt  
long nFileLength; //文件长度 %}zkmEY.e  
boolean bFirst = true; //是否第一次取文件 4D<C;>*/b  
boolean bStop = false; //停止标志 O<L=N-  
File tmpFile; //文件下载的临时信息 U*Y]cohh  
DataOutputStream output; //输出到文件的输出流 2/V%jS[4#y  
|T/OOIA=sI  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） a5ZXrWv  
public SiteFileFetch(SiteInfoBean bean) throws IOException N1c0>{  
{ GfK%UZ$C  
siteInfoBean = bean; `f&::>5tD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a*X{hU9P  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g3[-[G
^5  
if(tmpFile.exists ()) ([rn.b]  
{ _,(s  
bFirst = false; I)` +:+P  
read_nPos(); ^VMCs/g6  
} "xTVu57Z[  
else TS+jDs  
{ o jxK8_kl  
nStartPos = new long[bean.getNSplitter()]; wH@S$WT  
nEndPos = new long[bean.getNSplitter()]; Yu)GV7\2  
} {X?1}5ry  
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+ <E zv  
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} BRY/[QRqZ  
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public void run() }1k?th  
{ *Us}E7/"'  
//获得文件长度 L(Twclrb  
//分割文件 {vW0O&[  
//实例FileSplitterFetch LFi* O&  
//启动FileSplitterFetch线程 ;DnUeE8  
//等待子线程返回 vI(LIfe;  
try{ dz/@]a  
if(bFirst) 1DAU*^-  
{ *`w>\},su  
nFileLength = getFileSize(); m`8{arz2  
if(nFileLength == -1) J>T98y/))  
{ &XcPHZy'  
System.err.println("File Length is not known!"); z)^.ai,:0  
} j~ds)dW%`&  
else if(nFileLength == -2) GEVDXx>@  
{ 'do2n/  
System.err.println("File is not access!"); Uq'W<.v5  
} S{e3aqT#N  
else 9<3}zwJ  
{ dg#Pb@7a  
for(int i=0;i<nStartPos.length;i++) C|Gk}  
{ JSju4TQ4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ._]Pz6  
} qvy*; <w  
for(int i=0;i<nEndPos.length-1;i++) RiR],Sj  
{ Q~wS2f`)  
nEndPos = nStartPos[i+1]; J`[jub  
} wI 7gHp  
nEndPos[nEndPos.length-1] = nFileLength; #P}n+w_@  
} |gxPuAXa)  
} tF/Ni*\^rV  
#=y)Wuo=  
ESoC7d&.K{  
//启动子线程 'Y ,2CN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; x5PM]~"p  
for(int i=0;i<nStartPos.length;i++) x(EwHg>;  
{ mpk+]n@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nTGf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F?a 63,r  
nStartPos,nEndPos,i); "pK<d~Wu  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2Uf/'  
fileSplitterFetch.start(); G/3T0d+-  
} /]J\/Z>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9@"pR;X@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); kGnT4R*E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1CZO+MB&"$  
nEndPos = " + nFileLength); d42Y`Wu  
// fileSplitterFetch[nPos.length-1].start(); zq$L[X  
+\ "NPK@3  
.7Yox1,  
//等待子线程结束 5({_2meJ:  
//int count = 0; X8*~Cf73u  
//是否结束while循环 F~rl24F  
boolean breakWhile = false; l{^
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L{IMZ+IB2|  
6l4=  
while(!bStop) Z5U\>7@&8  
{ G^h:#T
  
write_nPos(); g^|R;s{  
Utility.sleep(500); v8C($<3%  
breakWhile = true; *rxYal4ad  
qk^/&j  
|/xA5_-N  
for(int i=0;i<nStartPos.length;i++) ~};q/-[r  
{ WY@g=W>+  
if(!fileSplitterFetch.bDownOver) YSPUQ  
{ uUq= L  
breakWhile = false; l-c:'n  
break; &D-z|ZjgHi  
} U&*%KPy`  
} 9L-jlAo<  
if(breakWhile) 1]0;2THx  
break; 5Zhl@v,L%  
KCZ<#ca^  
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//count++; jbZTlG  
//if(count>4) I~~":~&  
// siteStop(); ) 5Ij  
} $E;Tj|W  
ydY(*]  
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"  
System.err.println("文件下载结束！"); fXnewPr=#  
} *a|575e< z  
catch(Exception e){e.printStackTrace ();} se>\5k  
} pd,d"+  
/TB{|_HbW  
*6u2c%^  
//获得文件长度 #>G:6'r  
public long getFileSize() /!>OWh*~  
{ 4IY|<  
int nFileLength = -1; ]3 GO_tL  
try{ ?9eiT:2  
URL url = new URL(siteInfoBean.getSSiteURL()); zNo"P[J8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %{V7|Azt  
httpConnection.setRequestProperty("User-Agent","NetFox"); Fo;J3<U)  
,1CmB@  
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int responseCode=httpConnection.getResponseCode(); SQ+r'g  
if(responseCode>=400) 1VG]|6f  
{ t(6i4c>  
processErrorCode(responseCode); wRK27=\z  
return -2; //-2 represent access is error m&q0 _nay  
} :6(@P1vA 6  
47{5{/B-  
{/5aF_0D.  
String sHeader;  o4yl3o  
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(w"(RM~  
for(int i=1;;i++) WQ:Y NmQ1p  
{ GZx*A S]+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :YkAp9civ  
//Utility.log(in.readLine()); {=&({ cS  
sHeader=httpConnection.getHeaderFieldKey(i); uxKO"  
if(sHeader!=null) Z'5&N5hx  
{ s7:_!Nd@8  
if(sHeader.equals("Content-Length")) y>h9:q|  
{ pNQ7uy  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |Go$z3bx  
break; aTH$+f1?Q  
} D-i, C~W  
} w03Ur4>T  
else WH7UJCQ  
break; {LA?v& b'  
} a!u5}[{  
} Rq?t=7fX)  
catch(IOException e){e.printStackTrace ();} /d"@$+  
catch(Exception e){e.printStackTrace ();} PX23M|$!  
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LH_U#P`E  
Utility.log(nFileLength); 1.8"N&s  
|)&d9|
]  
5{DwD{Q  
return nFileLength; -U_,RMw~  
} ~g#/q~UE  
suWO:]FR  
fY78  
//保存下载信息（文件指针位置） HSU?4=Q  
private void write_nPos() SfY9PNck\  
{ %FqQ+0^  
try{ `/!FZh<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C"s-ttP   
output.writeInt(nStartPos.length); $T7 qd  
for(int i=0;i<nStartPos.length;i++) Nvh&=%{g  
{ 15' fU!  
// output.writeLong(nPos); 9!Xp+<  
output.writeLong(fileSplitterFetch.nStartPos); R1%J6wZq  
output.writeLong(fileSplitterFetch.nEndPos); Q%J,:
J  
} S}]B|Q  
output.close(); OZ"76|H1`  
} !g=b=YK  
catch(IOException e){e.printStackTrace ();} -F
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catch(Exception e){e.printStackTrace ();} 5gC>j(  
} 5e0d;Rd  
),j6tq[  
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//读取保存的下载信息（文件指针位置）
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private void read_nPos() MOp "kA  
{ W_3BL]^=  
try{ M_r[wYt!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K3,PmI&W  
int nCount = input.readInt(); oJ"D5d,  
nStartPos = new long[nCount]; |m@>AbR5dk  
nEndPos = new long[nCount]; +StsSZ  
for(int i=0;i<nStartPos.length;i++) w&J_c8S  
{ 8ZCA vEy  
nStartPos = input.readLong(); ]gaeN2  
nEndPos = input.readLong(); HPt\ BK  
} d'3"A"9R7-  
input.close(); Ss
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} &k-NDh3  
catch(IOException e){e.printStackTrace ();} 7-u'x[=m  
catch(Exception e){e.printStackTrace ();} Q&?0 ^;r  
} F8Mf,jnPs  
#qD[dC$[t  
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private void processErrorCode(int nErrorCode) ];b+f@  
{ V3d$C&<(  
System.err.println("Error Code : " + nErrorCode); sdyNJh7Jr  
} u$(ei2f  
({!H()  
j?k|-0  
//停止文件下载 87eH~&<1  
public void siteStop() C=cn.CX  
{ ]?oJxW.  
bStop = true; e-\/1N84  
for(int i=0;i<nStartPos.length;i++) 3MKu!  
fileSplitterFetch.splitterStop(); ucU7 @j  
N`N?1!fM<}  
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} ~ L>M-D4o  
} h%4UeL &F  
//负责部分文件的抓取 ;#0$iE  
**FileSplitterFetch.java D.x8=|;  
*/ gNA!)}m\  
package NetFox; unbIfl=  
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import java.io.*; V d]7v  
import java.net.*; |GsMLY:0  
M_2>b:#A*  
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public class FileSplitterFetch extends Thread { LEOa=(mN\  
l+hOD{F4pS  
Em5,Zr_  
String sURL; //File URL u%I%4 gM  
long nStartPos; //File Snippet Start Position #e,TS`"eD  
long nEndPos; //File Snippet End Position kp}[nehF  
int nThreadID; //Thread's ID s@y;b0
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boolean bDownOver = false; //Downing is over oGl<i  
boolean bStop = false; //Stop identical .c0u##/0  
FileAccessI fileAccessI = null; //File Access interface 6iF&!Fd>J  
ki/Cpfq40*  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vH1,As  
{ ;$gV$KB:xA  
this.sURL = sURL; )& Oxp&x  
this.nStartPos = nStart; `NEi/jB  
this.nEndPos = nEnd; IA[:-2_  
nThreadID = id; S $o1Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &1&OXm$  
} MV!d*\  
;FF+uK  
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public void run() #<Xq\yC51  
{ l"DHG`kb  
while(nStartPos < nEndPos && !bStop) ,R3
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{ m.! M#x2!  
t,*1=S5  
5;XYF0  
try{ ED" fi$  
URL url = new URL(sURL); XuHR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I.T?A9Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); v-q-CI?B#  
String sProperty = "bytes="+nStartPos+"-"; 6akI5\b  
httpConnection.setRequestProperty("RANGE",sProperty); $?]`2*i  
Utility.log(sProperty); *FZav2]-  
4#]g852  
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InputStream input = httpConnection.getInputStream(); \@N~{72:k  
//logResponseHead(httpConnection); g7*Uuh#  
A*81}P_  
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byte[] b = new byte[1024]; W83PMiN"T-  
int nRead; bGK*1FlH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k<+Sj h$  
{ d ePk}Sn  
nStartPos += fileAccessI.write(b,0,nRead); U=69q]  
//if(nThreadID == 1) B7|%N=S%/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <j,3D
n  
} e.%I#rNI  
~9yKMUf  
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Utility.log("Thread " + nThreadID + " is over!"); m{X{h4t  
bDownOver = true; Dc$q0|N=z  
//nPos = fileAccessI.write (b,0,nRead); Pc< "qy  
} :9%e:-  
catch(Exception e){e.printStackTrace ();} c ^.^5@  
} 1r}i[5  
} \=im{(0h  
8AY;WL:;  
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//打印回应的头信息 SG|AJ9  
public void logResponseHead(HttpURLConnection con) ge6S
_"
 
{ ?< teHFj  
for(int i=1;;i++) ]sL.+.P  
{ Y;huTZ  
String header=con.getHeaderFieldKey(i); t!6uz  
if(header!=null) a=A12<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); jl(D;JnF  
Utility.log(header+" : "+con.getHeaderField(header)); E QU@';~8  
else fDplYn#  
break; Qj_)^3`e  
} x>TIx[x  
} }5(_gYr  
Cb? !+U  
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public void splitterStop() X1a~l|$h  
{ CrL9|78  
bStop = true; ]BbV\#  
} `Ds=a`^b  
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hZL!%sL7  
} vo\'ycPv  
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/* ht]n*  
**FileAccess.java Q[K$f%>  
*//文件访问(定位，写) 1+N'cB!y  
package NetFox; ]GY8f3~|{  
import java.io.*; 8Nyz{T[  
'iZwM>l\  
0=6mb]VUi=  
public class FileAccessI implements Serializable{ 1t &_]q_  
g|?}a]G  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %%?}db1n  
RandomAccessFile oSavedFile; 0|tyKP|J  
long nPos; Kb<c||2Nh5  
iJOG"gI&  
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public FileAccessI() throws IOException S|k@D2k=  
{ bO/r1W  
this("",0); (:`4*xK  
} JU^Y27  
VV/T)qEe7>  
.[]S!@+%  
public FileAccessI(String sName,long nPos) throws IOException P[q>;Fx*  
{ %#v$d  
oSavedFile = new RandomAccessFile(sName,"rw"); 6wwbH}*=?  
this.nPos = nPos; iBbaHU*V  
oSavedFile.seek(nPos); :'C?uk ?  
} -p)`ob-  
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f&^}yqmuE  
public synchronized int write(byte[] b,int nStart,int nLen) 3MHpP5C  
{ p19(>|$J  
int n = -1; .$x}~Sw  
try{ 9v*y&V9/  
oSavedFile.write(b,nStart,nLen); JluA?B7E  
n = nLen; >h#juO
"  
} mkyYs[  
catch(IOException e) pqpsa'  
{ ?#:']q  
e.printStackTrace (); *f;$5B#^  
} dO1
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return n; RxJbQs$Ph  
} [9Rh"H;h  
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} NdLe|L?c  
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/* K3 BWj33  
**SiteInfoBean.java ~< UYJc  
*/ tg#jjXV\0p  
package NetFox; dazML|1ow  
6*S/frE  
GiuE\J9i  
public class SiteInfoBean { (EWGX |QA  
Khi6z&B  
P
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private String sSiteURL; //Site's URL vjm? X  
private String sFilePath; //Saved File's Path a1I-d=]  
private String sFileName; //Saved File's Name ~Uv#)  
private int nSplitter; //Count of Splited Downloading File y4p"LD5%^  
44P [P{y  
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public SiteInfoBean() M=;csazN  
{//nSplitter的缺省值为5 G5t7KI  
//default value of nSplitter is 5 gE@Pb  
this("","","",5); dS 4/spNq  
} FN!?o:|(  
*lL
CH,  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?_AX;z  
{ 8i73iTg(  
sSiteURL= sURL; Z9 ws{8@_  
sFilePath = sPath; w)vpo/?  
sFileName = sName; vmkiw1  
this.nSplitter = nSpiltter; )#
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} L9Zz-Dr s  
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k CGb~+  
public String getSSiteURL() AT
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{ uQ[,^Ee&/  
return sSiteURL; 420K6[  
} }\8-&VoY#X  
6o6yx:  
fI0"#iv}  
public void setSSiteURL(String value) |?0MRX0'g  
{ ;7qzQ{Km  
sSiteURL = value; 6vNn;-gg.  
} %4x0^<k~  
%{r3"Q=;W  
DUu:et&c1  
public String getSFilePath() |-{ Hy(9  
{ h+H+>,N8`  
return sFilePath; D}!YF~  
} DQ={  
pwHe&7e#  
4>L*7i  
public void setSFilePath(String value)  jMI30  
{ Q Rr9|p{  
sFilePath = value; [>p!*%m  
} ( EJ1g^|"  
;5\'PrE  
0~$9z+S  
public String getSFileName() DcaKGjp  
{ |;Jt* _  
return sFileName; /
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} R{A$|Ipaq  
JleClB(2n/  
qrw*?6mSQ  
public void setSFileName(String value) =eW4?9Uq  
{ *zweZG8:  
sFileName = value; K-Pcew^?  
} 1qn/*9W}=  
X.#9[3U+  
FPK=Tr:b  
public int getNSplitter() VK*H1EH1  
{ .tfal9  
return nSplitter; Vtj*O'0  
} A~>B?Wijqg  
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z)*{bz]  
public void setNSplitter(int nCount) lAA6tlc#C  
{ ='kCY}dkO  
nSplitter = nCount; o(54 A['  
} n>Oze7hVY  
} 1 <T|  
%|JL=E}%|  
V:5aq.o!  
/* };9/J3]m  
**Utility.java *tpS6{4=#7  
*/ A9ld9R  
package NetFox; 9{SzE /[  
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i  
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public class Utility { N,9~J"z  
W4nn)qBrh  
,s}&|+ '"  
public Utility() uInI{>  
{ (?,jnnub  
ESIJ QM-[+  
H[pvC=O=  
} d?YSVmG  
sLTQm*jL  
//线程睡眠 qycf;Kl:6  
public static void sleep(int nSecond) HXdo:#xEO  
{ /u]#dX5  
try{ =$^}"}$  
Thread.sleep(nSecond); M54czo=l  
} &l-d_dh  
catch(Exception e) HtE^7i*_  
{ 438r]f?0|{  
e.printStackTrace (); DrBkR`a?  
} jc>B^mqx  
} Jk|DWZ  
/:\27n  
//日志 dKDCJt]t  
public static void log(String sMsg) W>{&" 5  
{ Jz&dC  
System.err.println(sMsg); IJPyCi)  
} OO
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t^6ams$  
2|RxowXZ"  
public static void log(int sMsg) ^l ;Bo3^_  
{ !_c6 `oW  
System.err.println(sMsg); z8D,[`  
} I)*J,hs1  
} Mjl,/-0 w  
qnd] UUA^  
_Y6Ezh.  
/* eo!+UFZbY  
**TestMethod.java 8QKu  
*/ W S9:*
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package NetFox; BjjuZN&  
SZ4@GK  
,@N.v?p>  
public class TestMethod { ojj T  
[CV0sYEA  
|D'!.$7%  
public TestMethod() F$:mGyl5_  
{ ///xx/weblogic60b2_win.exe Q3t%JP>;g  
try{ =q"0GUei3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -biw{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X^m@*,[s  
SiteFileFetch fileFetch = new SiteFileFetch(bean); V0#E7u`4  
fileFetch.start(); 'rfs
rZ?  
} h"2^` )!u  
catch(Exception e){e.printStackTrace ();} JiA1yt  
s1%2({wP  
[P)](8nR[  
} 5*B'e{C  
^ 6t"A  
.rDao]K  
public static void main(String[] args) 8|hi2Qeu,c  
{ "4*QA0As  
new TestMethod(); cZWW[i  
} 4l/~::y  
} .Z17X_  
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