http断点续传简单实现（java)

/* 57U%`  
**SiteFileFetch.java pzg&/m&F`  
*/ xo(k?+P>.  
package NetFox; >{QdMn  
import java.io.*; +lKrj\Xj  
import java.net.*; X($6IL6m  
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public class SiteFileFetch extends Thread { v~}5u 5$O  
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SiteInfoBean siteInfoBean = null; //文件信息Bean t=i/xG:5  
long[] nStartPos; //开始位置 OTE<x"=h  
long[] nEndPos; //结束位置 ywEDy|Wn$~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Mb/L~gd"  
long nFileLength; //文件长度 "7d.i(vw  
boolean bFirst = true; //是否第一次取文件 6|^0_6_  
boolean bStop = false; //停止标志 AFm,CINa  
File tmpFile; //文件下载的临时信息 =-qf;5[|  
DataOutputStream output; //输出到文件的输出流 y@
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） jN6b*-2  
public SiteFileFetch(SiteInfoBean bean) throws IOException "J!}3)n  
{ Oqmg;\pm  
siteInfoBean = bean; 5%P[^}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \vVSh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .'/l'>  
if(tmpFile.exists ()) ?+Q$#pb  
{ _88QgThb  
bFirst = false; {5-zyE  
read_nPos(); D%U:!|G  
} f05=Mc&)  
else &K *X)DAs  
{ 4\6:\  
nStartPos = new long[bean.getNSplitter()]; sa9fK Z'q  
nEndPos = new long[bean.getNSplitter()]; !| xZ6KV  
} E:w:4[neh  
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} "OL~ul5  
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public void run() @Tr&`Hi  
{ HE;V zR  
//获得文件长度 <GF@L  
//分割文件 o@/xPo|  
//实例FileSplitterFetch %!y89x=E  
//启动FileSplitterFetch线程 p7C!G1+z  
//等待子线程返回 3wC R|ab}  
try{ \zu}\{  
if(bFirst) xmr|'}Pt[  
{ U-EhPAB@  
nFileLength = getFileSize(); ((|IS[  
if(nFileLength == -1) })[($$f/  
{ K\&o2lo]  
System.err.println("File Length is not known!"); p<5!02yQ\  
} xU}M;4kH~  
else if(nFileLength == -2) hCC}d0gf`n  
{ kH?#B%N5  
System.err.println("File is not access!"); P`TIaP9%E  
} [w+Q^\%bN  
else )~ z Z'^  
{ S&?7K-F>_o  
for(int i=0;i<nStartPos.length;i++) n
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{ m^I,}1H4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jGD%r~lN  
} G{RTH_p
 
for(int i=0;i<nEndPos.length-1;i++) 6>DLp}d  
{ ]V<-J   
nEndPos = nStartPos[i+1]; ssl&5AS  
} n &}s-`D  
nEndPos[nEndPos.length-1] = nFileLength; \%5MAQS  
} Y=2Un).&  
} q`Q}yE>9  
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//启动子线程 ^8K/xo-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <1@ (ioPH  
for(int i=0;i<nStartPos.length;i++) u~F~cDu  
{ S%l:kKD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @Zm Jz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ndi+xaQtG  
nStartPos,nEndPos,i); j*zD0I]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kMxjS^fr  
fileSplitterFetch.start(); -MfQ&U  
} {gU&%j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2]ti!<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pbn\9C/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [,g~m9  
nEndPos = " + nFileLength); tcL2J.  
// fileSplitterFetch[nPos.length-1].start(); W3JF5*  
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S>f&6ZDNY(  
//等待子线程结束 ]J@/p:S
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//int count = 0; *jCW.ZLY  
//是否结束while循环 44-r\>  
boolean breakWhile = false; WzlC*iv  
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while(!bStop) C1fyV]  
{ PC/!9s0W  
write_nPos(); c K<)$*  
Utility.sleep(500); -:`V<  
breakWhile = true; u#jC#u^M  

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for(int i=0;i<nStartPos.length;i++) Ade}g'  
{ xPC"c*  
if(!fileSplitterFetch.bDownOver) #n7Yr,|Z  
{ >D_F!_  
breakWhile = false; z<n-Gzwk  
break; &<1`O  
} 
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} 2\@Z5m3B  
if(breakWhile) bFGDgwe z  
break; hbfq]v*X  
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//count++; |g_g8[@`}  
//if(count>4) OO-k|\{|  
// siteStop(); qd6fU^)i  
} 9&  
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System.err.println("文件下载结束！"); v1+U;Th>g  
} p>kq+mP2bc  
catch(Exception e){e.printStackTrace ();} 8r:M*25  
} Yl({)qK{  
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//获得文件长度 ,=PKd&  
public long getFileSize() $c9k*3{<+A  
{ r"wtZ]69  
int nFileLength = -1; tP(h9|[
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try{ 1ThqqB  
URL url = new URL(siteInfoBean.getSSiteURL()); Vxdp|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0A[esWmP  
httpConnection.setRequestProperty("User-Agent","NetFox"); K-Mc6  
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int responseCode=httpConnection.getResponseCode(); wL{qD  
if(responseCode>=400) ejePDgi_[  
{ cxP
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processErrorCode(responseCode); zG9|K  
return -2; //-2 represent access is error X?Pl<l&  
} HuI`#.MpWE  
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String sHeader; 07_oP(;jT  
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for(int i=1;;i++) jai|/"HSXw  
{ }iiHr|l3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ocQWQ   
//Utility.log(in.readLine()); eV!L^>>>  
sHeader=httpConnection.getHeaderFieldKey(i); gNj7@bX~  
if(sHeader!=null) i*[n{=*l@  
{ yfj(Q s  
if(sHeader.equals("Content-Length")) ZI13  
{ \~DM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _GA$6#]  
break; +RDJY(Y$  
} }*wLEa  
} hv)8K'u
 
else -4 Ux,9
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break; ,T5u
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} ~}ovuf=%  
} 4g` jd  
catch(IOException e){e.printStackTrace ();} 4_=Ja2v8;`  
catch(Exception e){e.printStackTrace ();} OI/@3"L{  
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Utility.log(nFileLength); ?u$u?j|N  
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return nFileLength; ^4>k%d  
} p3x?[Ww  
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//保存下载信息（文件指针位置） u?H 2%hD  
private void write_nPos() g
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{ a:Q[gF
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try{
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output = new DataOutputStream(new FileOutputStream(tmpFile)); t;q7t!sC]  
output.writeInt(nStartPos.length); 9U_ks[Qa  
for(int i=0;i<nStartPos.length;i++) E1V^}dn  
{ IyUdZ,ba  
// output.writeLong(nPos); JAb6zpP  
output.writeLong(fileSplitterFetch.nStartPos); LF<wt2?*  
output.writeLong(fileSplitterFetch.nEndPos); &9[P-w;7u  
} Y%`SHe7M  
output.close(); Ud%s^A
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} @tT-JwU  
catch(IOException e){e.printStackTrace ();} hlbvt-C?}"  
catch(Exception e){e.printStackTrace ();} ^rAa"p9  
} X]j)+DX>  
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//读取保存的下载信息（文件指针位置） #;VA5<M8  
private void read_nPos() MN8H;0g-  
{ J>0b1  
try{ ~Qj}ijWD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); PRu&3BP  
int nCount = input.readInt(); @tUoD>f  
nStartPos = new long[nCount]; 8F5|EpB9M  
nEndPos = new long[nCount]; Gpj* V|J  
for(int i=0;i<nStartPos.length;i++) 8G^<[`.@j  
{ 5p"BD'^:  
nStartPos = input.readLong(); \.{AAj^qD  
nEndPos = input.readLong(); wFS2P+e;X  
} v1G"3fy
9  
input.close(); }(FPV*mS  
} P87# CAN  
catch(IOException e){e.printStackTrace ();} K7TzF&  
catch(Exception e){e.printStackTrace ();} VDF)zA1V  
} wVl+]zB  
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#$ thPZ  
private void processErrorCode(int nErrorCode) %at
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{ K!z
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System.err.println("Error Code : " + nErrorCode); cDEJk?3+  
} nA7M8HB  
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//停止文件下载 8AFczeg[[  
public void siteStop() g(x9S'H3l  
{ 1eS_ nLFw~  
bStop = true; dR^"X3$  
for(int i=0;i<nStartPos.length;i++) %D}H|*IPu  
fileSplitterFetch.splitterStop(); .Nm su+s  
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} l{c]p-  
} &K+0xnUH  
//负责部分文件的抓取 2{,n_w?Wy  
**FileSplitterFetch.java +_l^ #?o,  
*/ jvy$t$az  
package NetFox; nR;D#"
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import java.io.*; `\u;K9S6  
import java.net.*; Y]|:?G7l]  
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public class FileSplitterFetch extends Thread { TtD@'QXq  
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String sURL; //File URL 0U/,aHvhP  
long nStartPos; //File Snippet Start Position sM[I4.A3  
long nEndPos; //File Snippet End Position |]=2 }%1w  
int nThreadID; //Thread's ID P(k(m<0  
boolean bDownOver = false; //Downing is over -Y 9SngxM  
boolean bStop = false; //Stop identical ykg#{9+  
FileAccessI fileAccessI = null; //File Access interface BG&c
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException hg@}@Wq\)  
{ T\s)le  
this.sURL = sURL; qSCv )S(  
this.nStartPos = nStart; V&]DzjT/  
this.nEndPos = nEnd; YV4#%I!<  
nThreadID = id; f$HH:^#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qm*}U3K  
} 0H_!Kg  
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public void run() _Us*+ 2(4L  
{ 9Mp$8-=>7  
while(nStartPos < nEndPos && !bStop) AwUi+|7r])  
{ #%@*p,xh  
,
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try{ ma$Prd  
URL url = new URL(sURL); @Y,7'0U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OYC_;CP  
httpConnection.setRequestProperty("User-Agent","NetFox"); iTh:N2/-vc  
String sProperty = "bytes="+nStartPos+"-"; e(F42;$$  
httpConnection.setRequestProperty("RANGE",sProperty); }U w&Ny  
Utility.log(sProperty); jDM w2#<  
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InputStream input = httpConnection.getInputStream(); x_
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//logResponseHead(httpConnection); 6&Juv  
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byte[] b = new byte[1024]; ;< )~Y-  
int nRead; ! Z`0(d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) juF{}J2  
{ + 1IQYa|  
nStartPos += fileAccessI.write(b,0,nRead); EVX{ 7%  
//if(nThreadID == 1) E@0
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PfS:AIy  
} Zc |/{$>:W  
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Utility.log("Thread " + nThreadID + " is over!"); $GQ`clj<  
bDownOver = true; [+*$\  
//nPos = fileAccessI.write (b,0,nRead); WnUweSdW  
}
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catch(Exception e){e.printStackTrace ();} $P7iRM]  
} '$As<LOEd/  
} SjjI
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//打印回应的头信息 bb42
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public void logResponseHead(HttpURLConnection con) e6X[vc|Y}  
{ 8By,#T".  
for(int i=1;;i++) .I VlEG0  
{ ?.c;
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String header=con.getHeaderFieldKey(i); E+"dq
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if(header!=null) < _$%@4 L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5Ft5@UF~  
Utility.log(header+" : "+con.getHeaderField(header)); 5G0
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else r!P}u  
break; FG3UZVUg9  
} #zrTY9m7  
} w#JJXXQI  
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public void splitterStop() U7xmC  
{ LAx4Xp/  
bStop = true; t:JI!DR  
} Z=4{
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} G5dO 3lwq  
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/* <]C$xp<2  
**FileAccess.java Kx"<J@  
*//文件访问(定位，写) FtufuL?JS  
package NetFox; <?D[9Mk$  
import java.io.*; wn>edn  
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public class FileAccessI implements Serializable{ E^_wI>  
Ae^X35  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /$n ~lf  
RandomAccessFile oSavedFile; DlMe5=n-u  
long nPos; #{r#;+  
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public FileAccessI() throws IOException 9/SXs0  
{ J" j.'.  
this("",0); pqvOJ#?Q}=  
} lcON+j  
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. .QB~  
public FileAccessI(String sName,long nPos) throws IOException #8{F9w<Rf  
{ ,3v+PIcMM+  
oSavedFile = new RandomAccessFile(sName,"rw"); N_4eM,7t  
this.nPos = nPos; s57N) 0kP  
oSavedFile.seek(nPos); QQk{\PV  
} IUGz =%[  
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public synchronized int write(byte[] b,int nStart,int nLen) -3Avs9`5  
{ , xx6$uZ  
int n = -1; q,<[hBri-  
try{ GwsY-jf  
oSavedFile.write(b,nStart,nLen); E< 4l#Z<  
n = nLen; 3`hUo5
K  
} n<Svwa}  
catch(IOException e) I4rPHZ|  
{ ufa41$B'yG  
e.printStackTrace (); p6EDQwlf  
} /9Q3iV$I]  
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return n; w&Dv8Wv+Oq  
} @J[6,$UVu  
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} 3[p_!eoW  
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/* ZZ/cq:3$P  
**SiteInfoBean.java ~:;3uLs,8  
*/ d
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package NetFox; \8uo{#cL8  
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public class SiteInfoBean { VvByHcLv  
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private String sSiteURL; //Site's URL C>^D*C(  
private String sFilePath; //Saved File's Path 4kp im  
private String sFileName; //Saved File's Name ,zcQS-e2  
private int nSplitter; //Count of Splited Downloading File UIJx*  
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public SiteInfoBean() ,7]k fB  
{//nSplitter的缺省值为5 `znB7VQ0  
//default value of nSplitter is 5 ~KjJ\b)R  
this("","","",5); lYf+V8{  
} WiNT;v[  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) wyc D>hc  
{ ,cTgR78'  
sSiteURL= sURL; Ar9nBJ`  
sFilePath = sPath; uE_c4Hp  
sFileName = sName; `T*U]/zQ  
this.nSplitter = nSpiltter; 4C_c\;d  
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} <T,
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public String getSSiteURL() C.a5RF0  
{ Lf}8qB#Y  
return sSiteURL; $Ptk|qFe  
} jdRq6U^  
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public void setSSiteURL(String value) hAR? t5c  
{ g1m
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sSiteURL = value; X'sEE  
} pck>;V  
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public String getSFilePath() 3*S[eqMJc  
{ R|,7d:k  
return sFilePath; C?m,ta
3  
} tn<6:@T  
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public void setSFilePath(String value) CDg AGy
 
{ 2=*=^)FNI  
sFilePath = value; eMMx8E)B  
} :xeLt;  
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public String getSFileName() n[k1np$7?6  
{ =G>(~+EA  
return sFileName; "e62/Ejg%  
} ;b~~s.+  
)^;DGzG  
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public void setSFileName(String value) U{1z;lJ  
{ Lyoor1   
sFileName = value; Ek
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} UVX"fZ)  
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public int getNSplitter() \KM|f9-b  
{ }=GM?,7b  
return nSplitter; oh\,O
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} QlzQ]:dWC  
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public void setNSplitter(int nCount) }p'8w\C$  
{ gg]~2f  
nSplitter = nCount; U</+.$b  
} jxY-u+B  
} n(&*kfk  
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/* Pz473d  
**Utility.java z+"0>ZN&  
*/ a-PGW2G  
package NetFox; FMS2.E  
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public class Utility { zqGYOm$r  
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public Utility() XiG88Kwv  
{ %0v*n8  
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} (3fPt;U  
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//线程睡眠 RndOm.TE  
public static void sleep(int nSecond) f[@#7,2~M  
{ (46U|P(v  
try{ Ihef$,  
Thread.sleep(nSecond); Oxn'bh6R0  
} ngq
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catch(Exception e) [+DNM 2A  
{ )dg UmN
 
e.printStackTrace (); <4NQL*|>  
} AIfk"2  
} +~:0Dxv W  
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//日志 Ph\F'xROe  
public static void log(String sMsg) Na;t#,  
{ ~y%7w5%Un  
System.err.println(sMsg); fiqj;GW  
} $y4M#yv  
=0Y'f](2eW  
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public static void log(int sMsg) m2MPWy5s  
{ g[<uwknf  
System.err.println(sMsg); _Fvsi3d/  
} cFxSDTR  
} h=mv9=x  
m-#d8sD2C  
| &\^n2`>  
/* Es,0'\m&  
**TestMethod.java +{bh  
*/ <v-92?  
package NetFox; @%7
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:if5z2PE/  
lZ+/\s,]|  
public class TestMethod { ^f"&}%"M  
{kv
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^:$j:w?j  
public TestMethod() *xho  
{ ///xx/weblogic60b2_win.exe B)(w%\M4^  
try{ zkvH=wL  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6UtG-WHHt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5vl2yN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); yl|R:/2V  
fileFetch.start();  K oL%}u&  
} ol1AD: Ho  
catch(Exception e){e.printStackTrace ();} 34^Q5B~^J  
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} aw;{<?*  
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public static void main(String[] args) +2f> M4q  
{ 9 ?[4i'  
new TestMethod(); <:H  
} SlM>";C\  
} d u_O}x  
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