http断点续传简单实现（java)

/* ^B8%Re%  
**SiteFileFetch.java P/5bNK!  
*/ Xm`jD'G  
package NetFox; -K hXb  
import java.io.*; h~)oiT2v  
import java.net.*; P*_
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public class SiteFileFetch extends Thread { p1 > D  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 9=7),`$  
long[] nStartPos; //开始位置 j38>,9u,  
long[] nEndPos; //结束位置 1A"h!;0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *xR;}%s\  
long nFileLength; //文件长度 -fFM-gt^t  
boolean bFirst = true; //是否第一次取文件 o6,$;-?F_  
boolean bStop = false; //停止标志 jE|Ju:}&  
File tmpFile; //文件下载的临时信息 D[U[D  
DataOutputStream output; //输出到文件的输出流 - ?_aYJ  
t-*oVX3D  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） H6X]D"Y,  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ve#VGlI  
{ teH $hd-q  
siteInfoBean = bean; FZ'|z8Dm  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <ek_n;R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); t"k6wv;Tq  
if(tmpFile.exists ()) Fn.wd`'0  
{ E,&BP$B  
bFirst = false; zim]3%b*A;  
read_nPos(); ^Lr)STh  
} nQ2V  
else k_?xiOSh  
{ xtMN<4#E  
nStartPos = new long[bean.getNSplitter()]; xzTTK+D@  
nEndPos = new long[bean.getNSplitter()]; N+%E=D>  
} :=WiT_M  
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} 3qU#Rg ;7  
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public void run() ]4wyuP,up  
{ >F+Mu-^  
//获得文件长度 ?JO x9;`  
//分割文件 :%cL(',Q  
//实例FileSplitterFetch ~`)`Ip  
//启动FileSplitterFetch线程 ( P|Ph  
//等待子线程返回 9,wd,,ta  
try{ n*~=O'  
if(bFirst) W<C \g~\  
{
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nFileLength = getFileSize(); (]7&][  
if(nFileLength == -1) yk OJhd3  
{ OEmz`JJ67  
System.err.println("File Length is not known!"); ]Tk3@jw+b  
} #ky]@vyO  
else if(nFileLength == -2) l6Wa~E  
{ LN}eD\  
System.err.println("File is not access!"); Nr)v!z~y   
} ][3H6T!ckL  
else pwAawm  
{ SQx%CcW9d  
for(int i=0;i<nStartPos.length;i++) bE:oF9J?  
{ O* `v1>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); SRs1t6&y=  
} =c>2d.^l  
for(int i=0;i<nEndPos.length-1;i++) 6p`AdDV  
{ ;/?M&rX  
nEndPos = nStartPos[i+1]; 2>BWu  
} )7@f{E#w  
nEndPos[nEndPos.length-1] = nFileLength; Lt>"R! "x  
} d\&{Ev9v  
} o}H7;v8H  
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//启动子线程 #G2~#\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (#x<qi,T  
for(int i=0;i<nStartPos.length;i++) .w=(
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{ Y/cnj n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }pOL[$L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W FVx7  
nStartPos,nEndPos,i); , 6 P:S7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Tbv", b
 
fileSplitterFetch.start(); >PdYQDyVS  
} >xQgCOi  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X+zFRL%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tSX<^VER7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", % C~
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nEndPos = " + nFileLength); ~ED8]*H|`  
// fileSplitterFetch[nPos.length-1].start(); ;|_aACina  
3a
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//等待子线程结束 |hBX"  
//int count = 0; KW.*LoO  
//是否结束while循环 v5STe`  
boolean breakWhile = false; 9}p>='  
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while(!bStop) ^uB9EP*P  
{ ?m.WqNBH7  
write_nPos(); S9/oBxGN  
Utility.sleep(500); 8xs}neDg*  
breakWhile = true; `x%v&>  

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for(int i=0;i<nStartPos.length;i++) u[
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{ xCU^4DO3p  
if(!fileSplitterFetch.bDownOver) q =sEtH=  
{ cQ(zBf  
breakWhile = false; '<! b}1w0  
break; A9Cq(L_H  
} ct,B0(]  
} X"_,#3Ko!  
if(breakWhile) gc``z9@Xg
 
break; }uWIF|h~  
2ghTAsUx9  
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//count++; *J^l r"%c  
//if(count>4) o5=1  
// siteStop(); Q9,H0r-%  
} e8T#ZWr*  
o!:V=F  
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System.err.println("文件下载结束！"); I(LBc  
} h| q!Qsnj'  
catch(Exception e){e.printStackTrace ();} w`_cmI  
} K_/-mwA v  

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//获得文件长度 9G njJ  
public long getFileSize() hP1}Do  
{ _$s ;QI]x  
int nFileLength = -1; pxm{?eBz  
try{ %`*`HU#X  
URL url = new URL(siteInfoBean.getSSiteURL()); 1Rrp#E}
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P<<?7_ ??  
httpConnection.setRequestProperty("User-Agent","NetFox"); M"QT(u+  
&!/E&e$_  
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int responseCode=httpConnection.getResponseCode(); A4;EtW+F  
if(responseCode>=400) Axb,{X[6g  
{ R9=K/  
processErrorCode(responseCode); 0\fV'JDOR  
return -2; //-2 represent access is error :[icd2JCw]  
} ,w>WuRN"  
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@9-/p^n1  
String sHeader; 2.''Nt6|  
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for(int i=1;;i++) c6 O1Z\M@\  
{ kmfz=
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J<K-Yeph  
//Utility.log(in.readLine()); <{$0mUn;s|  
sHeader=httpConnection.getHeaderFieldKey(i); M0Eq 7:Ba  
if(sHeader!=null) -M]NdgI  
{ \#1*r'V8  
if(sHeader.equals("Content-Length")) ]/byz_7]  
{ >`\f,yql6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ahezDDR-.i  
break; 21(8/F ~{  
} hC1CISm.U  
} zJ-_{GiM*L  
else }M3f ?Jv  
break; y"N7r1Pf  
} <*D{uMw  
} ,&+"|,m  
catch(IOException e){e.printStackTrace ();} Gyo[C98  
catch(Exception e){e.printStackTrace ();} 66A}5b4)]  
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Utility.log(nFileLength); NBLiwL37{  
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return nFileLength; ;Y/{q B!  
} um/2.Sn>  
$U3|.4  
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//保存下载信息（文件指针位置） P''5A6#5  
private void write_nPos() :.;pRz  
{ 4J#F;#iA  
try{ QU`M5{#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NO(^P+s  
output.writeInt(nStartPos.length); %BdQ.\4DS  
for(int i=0;i<nStartPos.length;i++) &b!L$@6  
{ !m7`E  
// output.writeLong(nPos); ].E89_|O  
output.writeLong(fileSplitterFetch.nStartPos); jZRf{  
output.writeLong(fileSplitterFetch.nEndPos); FG-v71!h#  
} q_0So}  
output.close(); I``S%`h  
} YH_m
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catch(IOException e){e.printStackTrace ();} +sN'Y/-  
catch(Exception e){e.printStackTrace ();} aT9+] Ig  
} qN5 ru2  
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//读取保存的下载信息（文件指针位置） j@yK#==k  
private void read_nPos() +>zjTP7\e"  
{ 2Fi~GY_  
try{ 4r'QP .h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [73 \jT  
int nCount = input.readInt(); i=m5M
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nStartPos = new long[nCount]; (s:ihpI  
nEndPos = new long[nCount]; cr}T ? $\K  
for(int i=0;i<nStartPos.length;i++) Uavr>-  
{ Z*AT &7  
nStartPos = input.readLong(); GM1z@i\5  
nEndPos = input.readLong(); M @|n"(P  
} IJWUNKqo=  
input.close(); H2f!c{t$p  
} jkTh)
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catch(IOException e){e.printStackTrace ();} x,CTB  
catch(Exception e){e.printStackTrace ();} dA)JR"r2  
} =rw60B  
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*=sMJY9#jE  
private void processErrorCode(int nErrorCode) x,U'!F  
{ 0_!')+  
System.err.println("Error Code : " + nErrorCode); (d> M/x?W  
} cRR[ci34k  
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,  
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//停止文件下载 %l4;-x<e  
public void siteStop() ^M:Y$9r_s  
{ zm
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bStop = true; &.m.ruab  
for(int i=0;i<nStartPos.length;i++) {;z{U;j  
fileSplitterFetch.splitterStop(); JJIlR{WY_  
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} k-:wM`C  
} q <, b  
//负责部分文件的抓取 #8Bs15aV  
**FileSplitterFetch.java u-8b,$@Z>'  
*/ S.<aCN<@  
package NetFox; a#huK~$~  
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import java.io.*; w5C$39e\G  
import java.net.*; ~CtLSyB  
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public class FileSplitterFetch extends Thread { lx'^vK%F  
:V9%R~h/  
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String sURL; //File URL mp!S<m  
long nStartPos; //File Snippet Start Position .S5%Qa [uW  
long nEndPos; //File Snippet End Position '-,$@l#  
int nThreadID; //Thread's ID 6`c5\G+  
boolean bDownOver = false; //Downing is over C`J>Gm  
boolean bStop = false; //Stop identical Qkvg85  
FileAccessI fileAccessI = null; //File Access interface ;+Dq3NE  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3jI rB%  
{ >3C4S  
this.sURL = sURL; {
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this.nStartPos = nStart; '3p7ee&  
this.nEndPos = nEnd; Jw4#u5$$Z  
nThreadID = id; ^v
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 1*aO2dOq  
} B~CdY}UTsj  
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public void run()
<M y+!3\A  
{ 3)6TnY/u6{  
while(nStartPos < nEndPos && !bStop) u~C,x3yr  
{ xg;o<y KF  
D2y[?RG  
nrF5^eZ#  
try{ IjPCaH.:t  
URL url = new URL(sURL); wHR# -g'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O)aWTI  
httpConnection.setRequestProperty("User-Agent","NetFox"); rA\6y6dFs  
String sProperty = "bytes="+nStartPos+"-"; Z!& u_  
httpConnection.setRequestProperty("RANGE",sProperty); /<R[X>]<F  
Utility.log(sProperty); }fV+Kd$CB  
fi,h`mdT?  
8v ZY+Q >  
InputStream input = httpConnection.getInputStream(); ; u@& [  
//logResponseHead(httpConnection); t@;r~Sb  
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byte[] b = new byte[1024];  LmZ"_  
int nRead; Y'{F^VxA/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W"v"mjYud  
{ ^.pd'  
nStartPos += fileAccessI.write(b,0,nRead); +_T`tmQ  
//if(nThreadID == 1) lz [s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {@&%Bq*&  
} xXRlQ|84  

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Utility.log("Thread " + nThreadID + " is over!"); \-W|)H  
bDownOver = true; Q1'4xWu  
//nPos = fileAccessI.write (b,0,nRead); W^k|*Y|  
} *}P=7TuS  
catch(Exception e){e.printStackTrace ();} M%z$yU`ac  
} qRcY(mb  
} Q H57[Yg  
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//打印回应的头信息 -<{;.~nI.  
public void logResponseHead(HttpURLConnection con) u85dG7  
{ cuoZ:
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for(int i=1;;i++) 6ec#3~ Y]  
{ 6Bf a
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String header=con.getHeaderFieldKey(i); mUdj2vB$+'  
if(header!=null) *DcB?8%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y,xJ5BI$  
Utility.log(header+" : "+con.getHeaderField(header)); !de`K |  
else 3JFX~"rV9I  
break; XCd[<\l
 
} TY`t3  
} E;bv;RUio  
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public void splitterStop() rQsYt/  
{ Tl!}Rw~Pg  
bStop = true; o JX4+uJ  
} $.F.xYS9IJ  
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} >]<4t06D  
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/* C0}@0c  
**FileAccess.java 60#eTo?}o  
*//文件访问(定位，写) >pm`(zLn  
package NetFox; ".7\>8A#a  
import java.io.*; 8)ykXx/f@  
mlO\wn-F  
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public class FileAccessI implements Serializable{ VCX^D)[-  
 =$-+~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 a797'{j#PI  
RandomAccessFile oSavedFile; 2_GbK-  
long nPos; WNS
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public FileAccessI() throws IOException se@?:n
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{
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this("",0); Bp-e< :  
} dT7!+)s5-  
;R([w4[~  
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public FileAccessI(String sName,long nPos) throws IOException /li
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{ ugzrG0=lx  
oSavedFile = new RandomAccessFile(sName,"rw"); uqvS  
this.nPos = nPos; ctMH5"F&1  
oSavedFile.seek(nPos); -BC`p 8  
} N}ZBtkR  
Th!;zu^t  
-<l2 $&KS  
public synchronized int write(byte[] b,int nStart,int nLen) Wi@YJ  
{ Vr:`?V9Q2(  
int n = -1; * /^}  
try{ $'n?V=4  
oSavedFile.write(b,nStart,nLen); ]P>c{  
n = nLen; 0{(5J,/BF  
} oTg 'N  
catch(IOException e) k] A(nr  
{ d*_rJE}B  
e.printStackTrace (); ^#!\VGnL  
} V-9\@'gc  
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return n; BB imP  
} #~ZaN;u  
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} t 7D~JAx6  
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/* & zv!cf  
**SiteInfoBean.java ?4
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*/ e F)my  
package NetFox; Pq,iR J  
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public class SiteInfoBean { i`5Skr:M  
&Qmb?{S0  
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private String sSiteURL; //Site's URL :{9HsF"h0  
private String sFilePath; //Saved File's Path z@?W
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private String sFileName; //Saved File's Name [)?yH3  
private int nSplitter; //Count of Splited Downloading File ft1V1 c  
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public SiteInfoBean() ji C2B  
{//nSplitter的缺省值为5 "u)e,gu  
//default value of nSplitter is 5 Z^Yy sf  
this("","","",5); Xp9] 9H.  
} tgj5l#P  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P$.$M}rMv  
{ 6mqp`x`  
sSiteURL= sURL; QjKh#sU&  
sFilePath = sPath; urg^>n4V]  
sFileName = sName; (Q=:ln;kM  
this.nSplitter = nSpiltter; bg5i+a,?  
g> m)XY  
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} 1p8pH$j'  
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public String getSSiteURL() $Gcj
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{ *z};&UsF{  
return sSiteURL; I|wC`VgB  
} B`YD>oCN  
CwD=nT5`  
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public void setSSiteURL(String value) {Wndp%  
{ k2(k0HFR  
sSiteURL = value; h.wffk,  
} 'e_e*.z3  
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public String getSFilePath() -qBdcbi|x)  
{ EQQ@nW{;  
return sFilePath; xd\ml 37~  
} <zm:J4&>T  
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+BDW1%  
public void setSFilePath(String value) $)$_}^.k  
{ I+( b!(H  
sFilePath = value; G#ELQ/Q  
} _St":9'uU  
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public String getSFileName() =!)x`1j!S  
{ ?dXAHY  
return sFileName; .[+}nA,g%~  
} jz
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tN.$4+  
hiv {A9a?  
public void setSFileName(String value) b7'l3mQjk  
{ %{rPA3Xoy  
sFileName = value; _SkiO}c8  
} 9
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public int getNSplitter() ,f@j4*)  
{ lI~8[[$xd  
return nSplitter; V5p^]To!  
} K{,'%|  
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public void setNSplitter(int nCount) @6Lp$w  
{  f^KN8N  
nSplitter = nCount; )~gIJW  
} eeBW~_W  
} gW<4E=fl  
RF;[:[*W  
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/* E
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**Utility.java olr-oi`4C  
*/ |~#A?mK
-  
package NetFox; IVy<>xpt  
oW(EV4J"  
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public class Utility { + )z5ai0m  
2.N)N%@  
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public Utility()  ZpMv16  
{ ]')y(_{  
%YbL%i|U  
a5aHv/W#P  
} 3t9CN )*  
cucmn*o?  
//线程睡眠 -ssmj8:Q\|  
public static void sleep(int nSecond) sAPQbTSM  
{ RNQq"c\  
try{ ^>>9?  
Thread.sleep(nSecond); ,F*HZBNFZ  
} A
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catch(Exception e) 5%4yUd#b  
{ ,CN(;
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e.printStackTrace (); Z"qJil}  
} bg/=P>2  
} P{BW^kAdH  
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//日志 {p$@)b  
public static void log(String sMsg) m9\"B3sr  
{ sCP|d`'  
System.err.println(sMsg); c##tP*(  
} `.dwG3R  
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6!
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public static void log(int sMsg) Ekik_!aB  
{
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System.err.println(sMsg); P;K LN9/4  
} CrSBN~  
} N-t"CBTO  
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/* mq:WBSsV  
**TestMethod.java US=K}B=g  
*/ )Vrp<"v  
package NetFox; ` AD}6O+x  
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public class TestMethod { j
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; yE.R[I  
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public TestMethod() o3eaNYa  
{ ///xx/weblogic60b2_win.exe )MLbE-@  
try{ FCOa|IKsN  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %W$b2N{l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (C1~>7L  
SiteFileFetch fileFetch = new SiteFileFetch(bean); CE!cZZ  
fileFetch.start(); P-$ ,  
} SS24@:"{  
catch(Exception e){e.printStackTrace ();} Slj U=,  
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c~ vql4  
} ==gL!e{  
mdQe)>  
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public static void main(String[] args) _~{J."q  
{ P;-.\VRu  
new TestMethod(); 2VUN  
} r%WHYhD  
} Oo-4WqRJ  
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