http断点续传简单实现（java)

/* &b"PjtU.X  
**SiteFileFetch.java 8eWb{nuJ>  
*/ r[EN`AxDb  
package NetFox; ,i>5\Yl%  
import java.io.*; h8pc<t\6  
import java.net.*; V9B $_j4  
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public class SiteFileFetch extends Thread { KXicy_@DC`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean N@tzYD|hA  
long[] nStartPos; //开始位置 N{|N_}X`Y  
long[] nEndPos; //结束位置 dYfVox;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \-V  
long nFileLength; //文件长度 m"H9C-Y  
boolean bFirst = true; //是否第一次取文件 sx`C<c~u  
boolean bStop = false; //停止标志 v,Ep2$  
File tmpFile; //文件下载的临时信息 7F)HAbIS  
DataOutputStream output; //输出到文件的输出流 3o"~_l$z  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） s7a\L=#p(  
public SiteFileFetch(SiteInfoBean bean) throws IOException Bk?MF6  
{ ',J3^h!b  
siteInfoBean = bean; DC[-<:B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -2% []  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O23f\pm&  
if(tmpFile.exists ()) 6M612  
{ Bz/NFNi[p  
bFirst = false; W9a H]9b  
read_nPos(); }1X,~y]  
} Tvf]OJ9N  
else {U-VInu  
{ }v=q6C#Q>  
nStartPos = new long[bean.getNSplitter()]; 'T+3tGCy+  
nEndPos = new long[bean.getNSplitter()]; ;rd!kFd#bq  
} |}'}TYX0:  
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} =0x[Sa$&,  
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public void run() "F)7!e  
{ Q:=s99  
//获得文件长度 RFQa9Rxk  
//分割文件 U/0NN>V  
//实例FileSplitterFetch j_p.KF'[?  
//启动FileSplitterFetch线程 Lrr6z05FQ  
//等待子线程返回 2 B5kpmH:  
try{ "qQU ^FW  
if(bFirst) f[h=>O  
{ @36^4E>h  
nFileLength = getFileSize(); PJh\U1Z  
if(nFileLength == -1) D@O'8  
{ #Cbn"iYee  
System.err.println("File Length is not known!"); ]O&TU X@)  
} @: %}clZ  
else if(nFileLength == -2) %# J8
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{ .+{nfmc,c  
System.err.println("File is not access!"); _%Mu{Ni&  
} -D{~7&  
else \=,+weGw@  
{ CF =#?+x  
for(int i=0;i<nStartPos.length;i++) .^P^lQT]>  
{ 4lvo9R
 
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y5PIR9-  
} Dzc 4
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for(int i=0;i<nEndPos.length-1;i++) !>9*$E |  
{ oBKZ$&_h  
nEndPos = nStartPos[i+1]; j!m~ :D  
} )p12SGR5  
nEndPos[nEndPos.length-1] = nFileLength; AvP*p{w
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} Y6^lKw  
} OXA_E/F  
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<Hm:#<\  
//启动子线程 P]r"E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "LXLUa
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for(int i=0;i<nStartPos.length;i++) dpE\eXoa,  
{ >G/>:wwSP.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  /=[M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), V/>SjUNq  
nStartPos,nEndPos,i); YfF&: "-NU  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nGX~G^mZ  
fileSplitterFetch.start(); pN4!*7M  
} .F)--%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?R"5 .3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); UY%@i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", y%ER51+  
nEndPos = " + nFileLength); v`beql  
// fileSplitterFetch[nPos.length-1].start(); EB@!?=0x  
!d
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//等待子线程结束 )-9|3`  
//int count = 0; z13"S(5D~  
//是否结束while循环 ] 
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boolean breakWhile = false; zS?i@e $  
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while(!bStop) f()^^+  
{ UPN2p&gM  
write_nPos(); ;CAB.aB~  
Utility.sleep(500); y7,~7f!N2  
breakWhile = true; t*.v!   
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for(int i=0;i<nStartPos.length;i++) ;F~GKn;}  
{ WxO*{`T!  
if(!fileSplitterFetch.bDownOver) IFpmf0;^  
{ .fD k5uo  
breakWhile = false; mjs*Z{_F^  
break; &Lq @af#  
} QW6k!ms$  
} pR\etXeLd  
if(breakWhile) $I1p"6  
break; Hyee#fB  
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//count++; `I m;@_J  
//if(count>4) "#e2"=3*  
// siteStop();  -U*XA  
} $V5Ol6@2  
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System.err.println("文件下载结束！"); 06Uxd\E~  
} dWm[#,Q?  
catch(Exception e){e.printStackTrace ();} de
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} ZU "y<  
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//获得文件长度 hj4A&`2  
public long getFileSize() Kh% x  
{ ={feN L  
int nFileLength = -1; 09x
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try{ aG=Y 6j G  
URL url = new URL(siteInfoBean.getSSiteURL()); (<%i8xu2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <T0-m?D_$  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]7xAL7x  
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int responseCode=httpConnection.getResponseCode(); fDbs3"H Q  
if(responseCode>=400) `yC R.3+  
{ *O 0*  
processErrorCode(responseCode); jj
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return -2; //-2 represent access is error
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} 6xBP72L;%"  
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String sHeader; possM'vC  
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for(int i=1;;i++)
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{ PfuYT_p4s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7rhpIP2n  
//Utility.log(in.readLine()); T-5T`awf  
sHeader=httpConnection.getHeaderFieldKey(i); h+$_:](PC  
if(sHeader!=null) H!45w;,I  
{ h_CeGl!M}  
if(sHeader.equals("Content-Length")) ".w*_1G7U  
{ |]m&LC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); nh E!Pk  
break; *dKA/.g  
} Tzk8y7$[  
} -k<.Q=]<t  
else _<3:vyfdC  
break; Z;n}*^U  
} L>@6lhD)x  
} BtqJkdK!;1  
catch(IOException e){e.printStackTrace ();} ZE=~ re  
catch(Exception e){e.printStackTrace ();} 4&$G;?#W2  
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Utility.log(nFileLength); awC&xVf  
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return nFileLength; 3cfkJ|fuwe  
} y'zEaL&SI@  
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//保存下载信息（文件指针位置） 3PJ  
private void write_nPos() AN.`tv  
{ }7C{:H2d  
try{ VKs$J)6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >2v_fw  
output.writeInt(nStartPos.length); | z('yy$  
for(int i=0;i<nStartPos.length;i++) L4[bm[x  
{ <~Y4JMr"  
// output.writeLong(nPos); E|5gKp-wJ  
output.writeLong(fileSplitterFetch.nStartPos); <4!w2vxG
 
output.writeLong(fileSplitterFetch.nEndPos); Y@r#:BH)  
} TvQAy/Y0  
output.close(); i;\i4MT  
} f|q6<n_nM  
catch(IOException e){e.printStackTrace ();} wZOO#&X#r  
catch(Exception e){e.printStackTrace ();} !IGVN:E  
} *v8 ]99N  
{?j|]j  
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//读取保存的下载信息（文件指针位置） "`3H0il;<  
private void read_nPos() \XpPb{:>  
{ ZRX>SyM
 
try{ @L~
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jV7q)\uu^  
int nCount = input.readInt(); <&x_e-;b'  
nStartPos = new long[nCount]; >"Hj=?  
nEndPos = new long[nCount]; F^aD!O ~  
for(int i=0;i<nStartPos.length;i++) @*_K#3  
{ 3'']q3H  
nStartPos = input.readLong(); (Ux%7H_d  
nEndPos = input.readLong(); da-3hM!u+  
} ^Krkf4fO  
input.close(); "~+K`*0r8  
} X0U6:  
catch(IOException e){e.printStackTrace ();} MP3E]T~:  
catch(Exception e){e.printStackTrace ();} d>aZpJ[.  
} nY*OD
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private void processErrorCode(int nErrorCode) `n%~#TJ  
{ =-:o?&64  
System.err.println("Error Code : " + nErrorCode); jAJkCCG  
} -I|yi'  
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//停止文件下载 -S|L+">=Z  
public void siteStop() t]vz+VQ  
{ $@U`zy
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bStop = true; .:;i*  
for(int i=0;i<nStartPos.length;i++) 2?"9NQvz  
fileSplitterFetch.splitterStop(); 2 Sr'B;`p  
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} xp39TiXJ*  
} kO5KZ;+N-  
//负责部分文件的抓取 b"zq3$6*  
**FileSplitterFetch.java :N[2*
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*/ =X1$K_cN  
package NetFox; Zkz:h7GUG-  
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import java.io.*; ,wFLOfV@  
import java.net.*; :._O.O  
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public class FileSplitterFetch extends Thread { ())|x[>JS+  
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String sURL; //File URL ^]v}AEcmW  
long nStartPos; //File Snippet Start Position HL)1{[|`  
long nEndPos; //File Snippet End Position ZWr\v!4  
int nThreadID; //Thread's ID :2?'mKa7  
boolean bDownOver = false; //Downing is over `^6}Dn  
boolean bStop = false; //Stop identical 6^
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FileAccessI fileAccessI = null; //File Access interface w|M?t{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y3~z#<  
{ ^n<YO=|u  
this.sURL = sURL; Tn/Zs|  
this.nStartPos = nStart; 
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this.nEndPos = nEnd; -BI!ZsC'  
nThreadID = id; ]\ !ka/%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ybsw{[X>M  
} =H8FV09x}  
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public void run() ||*F.p  
{ -0<vmU  
while(nStartPos < nEndPos && !bStop) ZO/Jf Jn~  
{ 7FPSBvU#/  
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try{ ?wl
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URL url = new URL(sURL); AZ4?N.X?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W|Sab$h  
httpConnection.setRequestProperty("User-Agent","NetFox"); _EP]|DTfr  
String sProperty = "bytes="+nStartPos+"-"; 0;T7fKj  
httpConnection.setRequestProperty("RANGE",sProperty); ZzgzeT+bv  
Utility.log(sProperty); Cw(ypu  
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InputStream input = httpConnection.getInputStream(); OomC%9/=,  
//logResponseHead(httpConnection); :<B_V<  
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byte[] b = new byte[1024]; ](Wa:U}Xs  
int nRead; Hcg7u7M{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #_S]\=N(  
{ $\vNSTE  
nStartPos += fileAccessI.write(b,0,nRead); Ns1n|^9  
//if(nThreadID == 1) HyWR&0J  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $V`1<>4  
} ,G46i)E\  
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Utility.log("Thread " + nThreadID + " is over!"); R= mTJ'y  
bDownOver = true; F1_,V?  
//nPos = fileAccessI.write (b,0,nRead); {V(~  
} KWjhkRK4]  
catch(Exception e){e.printStackTrace ();} Spx%`O<  
} 7- LjBlH  
} ko[d axUB  
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//打印回应的头信息 HH7WMYoKY  
public void logResponseHead(HttpURLConnection con) :vEfJSA 1<  
{ o[ks-C>jw  
for(int i=1;;i++) +FadOx7X$  
{ 'v0rnIsI?  
String header=con.getHeaderFieldKey(i); tF-l=ph}`  
if(header!=null) pGR3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); C@:X9NU  
Utility.log(header+" : "+con.getHeaderField(header)); Ad-5Znc5  
else O%>*=h`P  
break; r0[<[jEh  
} 9)S3{i6w  
} x"C7NW[$  
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public void splitterStop() l1<=3+d  
{ ,:J[|9  
bStop = true; #W8?E_iu  
} N;-%:nC  
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} $)KODI>|  
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/* FCwE/ 2,  
**FileAccess.java -eh .Tk  
*//文件访问(定位，写) 6A.%)whI;  
package NetFox; )i:*r8*~  
import java.io.*; (X\]!'A  
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public class FileAccessI implements Serializable{ OS<GA
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0  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 wY%t# [T3  
RandomAccessFile oSavedFile; m6K7D([f  
long nPos; 3`{ vx  
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public FileAccessI() throws IOException iQ2}*:Jc$  
{ 0$-|Th:o  
this("",0); oO3^9?Z  
} c*zeO@AAn  
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public FileAccessI(String sName,long nPos) throws IOException 7_jt =sr  
{ `5Z'8^  
oSavedFile = new RandomAccessFile(sName,"rw"); <=6F=u3PtU  
this.nPos = nPos; wVI_SQ<8V  
oSavedFile.seek(nPos); c C) <Y#1  
} 8|\ -(:v  
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public synchronized int write(byte[] b,int nStart,int nLen) r|uR!=*|?  
{ [hot,\+f  
int n = -1; >)*d/^  
try{ {%k[Z9*tO  
oSavedFile.write(b,nStart,nLen); #l-zY}&  
n = nLen; 9$9aBW  
} [hH>BEtm  
catch(IOException e) Y?K?*`Pkc1  
{ ALO/{:l(  
e.printStackTrace (); 5$>buYF  
} rc>}3?o  
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return n; wi.E$RckD  
} u-jc8W`Zd  
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} ^e_uprZWm  
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/* ]xb2W~  
**SiteInfoBean.java Ywt9^M|z;  
*/ "B"ql-K  
package NetFox; XJl 3\*  
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public class SiteInfoBean { fn7?g  
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private String sSiteURL; //Site's URL x+'Ea.^  
private String sFilePath; //Saved File's Path wM;=^br  
private String sFileName; //Saved File's Name `RURC"  
private int nSplitter; //Count of Splited Downloading File {H9
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public SiteInfoBean() ~SA>$  
{//nSplitter的缺省值为5 2t?>0)*m  
//default value of nSplitter is 5 =)iAU/*N  
this("","","",5); #\xy,C'Y  
} B 'd@ms  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7NvRZ!  
{ ?wIEXKI  
sSiteURL= sURL; QJx<1#  
sFilePath = sPath; #X{lV]Z  
sFileName = sName; (otD4VR_  
this.nSplitter = nSpiltter; [{`&
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} -J]N &[  
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public String getSSiteURL() CA$|3m9)NM  
{ v`7~#Avhz  
return sSiteURL; PCc{0Rp\vk  
} =XSupM[T  
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public void setSSiteURL(String value) ?4W6TSW-'  
{ ):L0{W{  
sSiteURL = value; K\lu;   
} i~4$V  
!\Xrl) $j{  
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public String getSFilePath() 6mIRa(6V  
{ uSxldc  
return sFilePath; uXG$YDKqC  
} 7<?Aou  
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public void setSFilePath(String value) d=g,s[FMm  
{ m^tf=O<  
sFilePath = value; h?->A#  
} ,C'mE''x  
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public String getSFileName()  SmAF+d
 
{ .SWn/Kk  
return sFileName; B/JMH 1r  
} 9}G<\y  
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public void setSFileName(String value) E@Yq2FBpnn  
{ R:44Gv7  
sFileName = value; M^/ZpKeT"  
} 0A75)T=lQ  
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public int getNSplitter() lt0byn$vz  
{ GM0pHmC  
return nSplitter; x^YsXzu  
} XpT~]q}  
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public void setNSplitter(int nCount) bI)%g  
{ ~=$d>ZNQ  
nSplitter = nCount; <;!#+|L/  
} 9_%??@^>  
} 5^{).fig  
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/* DC'L-]#<  
**Utility.java 2)|G%f_lS  
*/ o-<.8Z}>at  
package NetFox; ,GF(pCZzG  
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public class Utility { {jEEAH)  
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public Utility() &^F'ME  
{ Ap
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.  
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} {$_Gjv  
])Z p|?Y  
//线程睡眠 WWVQJ{,}  
public static void sleep(int nSecond) VO7&<Y}{x  
{ ?#/~BZR!  
try{ slG%o5|m  
Thread.sleep(nSecond); T$o;PJc  
} a)r
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catch(Exception e) zQsW*)L  
{ -b'/}zz  
e.printStackTrace (); #7naI*O  
} u 236a\:  
} F<Z13]|  
&MJ`rj[%  
//日志 q.d qr<  
public static void log(String sMsg) ?l](RI   
{ :}ZY*ind  
System.err.println(sMsg); /k=krAz.  
} X;yThb`iI  
g"X!&$
&  
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public static void log(int sMsg) md/NMC \  
{ )*
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System.err.println(sMsg); Ihx[S!:  
} E5t /-
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} (*V:{_r  
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/* o(oD8Ni  
**TestMethod.java @BI;H V%k  
*/ G5!!^p~  
package NetFox; @6{F4  
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public class TestMethod { wo\O0?d3{  
a- 7RJ.  
[&:dPd1_  
public TestMethod() F|?}r3{aJ  
{ ///xx/weblogic60b2_win.exe .}iRe}=  
try{ ZtX\E
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]nm(V  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;!#IRR  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
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fileFetch.start(); ?fNUmk^A<  
} /=:Fw}vt  
catch(Exception e){e.printStackTrace ();} |pR'#M4j4A  
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} 4\14HcTcK  
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public static void main(String[] args) OTmr-l6  
{ Kj#h9e  
new TestMethod(); yUg'^SEbLk  
} )wk9(|[o  
} -z>m]YDH  
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