http断点续传简单实现（java)

/* %ER"Udh  
**SiteFileFetch.java 5*O*p `Ba  
*/ uc<JF=  
package NetFox; kxanzsSr9  
import java.io.*; Y>/T+u
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import java.net.*; HUA{ P%  
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public class SiteFileFetch extends Thread { !*?|*\B^I  
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SiteInfoBean siteInfoBean = null; //文件信息Bean wit rC>  
long[] nStartPos; //开始位置 o7r7HmA@  
long[] nEndPos; //结束位置 Hk1[0)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O"M2*qiH  
long nFileLength; //文件长度 >\7Mf@c  
boolean bFirst = true; //是否第一次取文件 V&h{a8xa$  
boolean bStop = false; //停止标志 E/3i_R  
File tmpFile; //文件下载的临时信息 _qxBjB4t"a  
DataOutputStream output; //输出到文件的输出流 S8
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） |JL?"cc  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^ Fnag]qQ  
{ Ka_g3  
siteInfoBean = bean; ^Q\Hy\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 57K\sT4[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); BXb=NE  
if(tmpFile.exists ()) :R{pV7<O  
{ kR+7JUq]  
bFirst = false; 68?>#o865  
read_nPos(); +SB>
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} :R-_EY$k6  
else %/4_|.8u  
{ ]vflx^<?  
nStartPos = new long[bean.getNSplitter()]; xZ]QT3U+  
nEndPos = new long[bean.getNSplitter()]; +n%d,Pz  
} @DNwzdP  
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} uq2C|=M-x\  
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public void run() j8G$,~v  
{ x*sDp3f[*  
//获得文件长度 %Z
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//分割文件 M2$
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//实例FileSplitterFetch =fy\W=c  
//启动FileSplitterFetch线程 v:P=t2q  
//等待子线程返回 l>?f+70  
try{ 'T|EwrS j  
if(bFirst) ;X N Ahg7  
{ >V>`}TIH  
nFileLength = getFileSize(); :}R,a=N  
if(nFileLength == -1) f5Hv![x  
{ Q;s{M{u  
System.err.println("File Length is not known!"); 1bFGoLAEFl  
} lWn}afI  
else if(nFileLength == -2) e"%uOuIYX  
{ XtQwLH+F  
System.err.println("File is not access!"); N^M6*,F,J  
} EOZ 6F-':  
else ?t<g|H/|6  
{ \:g\?[   
for(int i=0;i<nStartPos.length;i++) {b'  
{ $NCR V:J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ZWni5uF-c  
} |2=@8_am  
for(int i=0;i<nEndPos.length-1;i++) 5UJ ?1"J  
{ V!(7=ku!`  
nEndPos = nStartPos[i+1]; )4h|7^6ji  
} $@vB<(sk  
nEndPos[nEndPos.length-1] = nFileLength; 5NC77}^.  
} {P,hH~!  
} ACy}w?D<  
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//启动子线程 3d]~e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; spTz}p^\O  
for(int i=0;i<nStartPos.length;i++) 1V9AnzwX  
{ `zrg?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hj(K*z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lo1bj*Y2  
nStartPos,nEndPos,i); LEOri=?RF  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Uf|uFGb  
fileSplitterFetch.start(); eEfGH  
} m+(g.mvK>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IdMwpru(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~-[!>1!%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }K@m4`T  
nEndPos = " + nFileLength); "dGN0i  
// fileSplitterFetch[nPos.length-1].start(); 4:S]n19nq  
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//等待子线程结束 Rnoz[1y?0  
//int count = 0; by0K:*C  
//是否结束while循环 D/Ok  
boolean breakWhile = false; /t`,7y3T  
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while(!bStop) X.S<",a{qz  
{ |OAM;@jH  
write_nPos(); qjhk#\y  
Utility.sleep(500); -.y1]4  
breakWhile = true; [|YvVA  
/g.c(-#]  

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for(int i=0;i<nStartPos.length;i++) Y#Q!mbp  
{ [OTn>/W'  
if(!fileSplitterFetch.bDownOver) zwU[!i)  
{ W7'<Jom|?  
breakWhile = false; ']>9/r#  
break; ?}v/)hjp=?  
} pDYJLh-C  
} NN2mOJ:-  
if(breakWhile) Ihf)gfHj  
break; B @QWr;  
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//count++; =cZ24I  
//if(count>4) Axns

  
// siteStop(); S<NK!89  
} J'sa{/ #  
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System.err.println("文件下载结束！"); yU&;\'  
} ~v;+-*t  
catch(Exception e){e.printStackTrace ();} ~tt\^:\3~S  
} d4BzFGsW  

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//获得文件长度 ]vB\yQE  
public long getFileSize() +a^gC  
{ y]+5Y.Cw$  
int nFileLength = -1; _~;%zFX  
try{ KcpYHWCa.  
URL url = new URL(siteInfoBean.getSSiteURL()); \u{4=-C.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .l_
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httpConnection.setRequestProperty("User-Agent","NetFox"); RC[Sa wA  
3: WEODV2  
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int responseCode=httpConnection.getResponseCode(); ;veD?|  
if(responseCode>=400) "r_wgl%  
{ J_Tz\bZ3)  
processErrorCode(responseCode); ZHN'j]?  
return -2; //-2 represent access is error AK,'KO%{=  
} 64mEZ_kG,  
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String sHeader; #f) TAA  
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for(int i=1;;i++) |&JeJ0k>~  
{ c/tB_]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hBpa"0F  
//Utility.log(in.readLine());
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sHeader=httpConnection.getHeaderFieldKey(i); PBb&.<  
if(sHeader!=null) 9/29>K_  
{ "E\mj'k  
if(sHeader.equals("Content-Length")) .gDq+~r8O  
{ \H:T)EV
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); C
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break; rX?ZUw?u&  
} hI!BX};+}  
} eNK +)<PK(  
else )h]#:,pm  
break; =?.oH|&\h  
} uStAZ~b\  
} O6G'!h\F  
catch(IOException e){e.printStackTrace ();} ]$Z:^"JS3  
catch(Exception e){e.printStackTrace ();} t kj  
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Utility.log(nFileLength); 3r kcIVO  
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return nFileLength; $xZ ~bE9  
} Cn3_D  
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&;d N:F;  
//保存下载信息（文件指针位置） K-C,n~-  
private void write_nPos() WV$CZgL  
{ {IV%_y?  
try{ \6&Ml]1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `9K5 ;]  
output.writeInt(nStartPos.length); 9m$;C'}Z  
for(int i=0;i<nStartPos.length;i++) <Pt?N2]A|  
{ Z)W8Of_  
// output.writeLong(nPos); Blzvn19'h  
output.writeLong(fileSplitterFetch.nStartPos); I61S0lz/  
output.writeLong(fileSplitterFetch.nEndPos); vlbZ5  
} E
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output.close(); xz"60xxY  
} `2s@O>RV  
catch(IOException e){e.printStackTrace ();} YkWHI(p  
catch(Exception e){e.printStackTrace ();} h7"U1'b  
} $q@d.Z>;  
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//读取保存的下载信息（文件指针位置） ,sAAV%">
 
private void read_nPos() Uv *Aa7M  
{ nFEJO&1+  
try{ Z*co\ pW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xeU|5-d'  
int nCount = input.readInt(); oM~y8O  
nStartPos = new long[nCount]; jn V=giBu  
nEndPos = new long[nCount]; w7U]-MW6A*  
for(int i=0;i<nStartPos.length;i++) 32\.-v  
{ aP  
nStartPos = input.readLong(); t Y  
nEndPos = input.readLong(); 6*9wGLE  
} \QK@wgu  
input.close(); S"Cz. bv  
} {g%N(2  
catch(IOException e){e.printStackTrace ();} &*<27-x  
catch(Exception e){e.printStackTrace ();} A ]A{HEX  
} sh$-}1 ;  
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private void processErrorCode(int nErrorCode) {'O><4  
{ SO0\d0?u  
System.err.println("Error Code : " + nErrorCode); $
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} !RmVb}m  
j HHWq>=d  
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//停止文件下载 V|MGG  
public void siteStop() ={:a N)  
{ .Ix3wR9  
bStop = true; ~ 1h#  
for(int i=0;i<nStartPos.length;i++) :*''ci  
fileSplitterFetch.splitterStop(); (G"'Fb6d  
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>  
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} n(F!t,S1i  
} q`<:CfCt  
//负责部分文件的抓取 P9cx&Hk9  
**FileSplitterFetch.java 2^WJ1: A  
*/ l/X_CM8y~  
package NetFox; l'+3 6  
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import java.io.*; Lj1l]OD  
import java.net.*; ;?2)[a  
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public class FileSplitterFetch extends Thread { ^Pn|Q'{/p  
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String sURL; //File URL IK2da@V  
long nStartPos; //File Snippet Start Position 2a$.S" ?  
long nEndPos; //File Snippet End Position C Bkoky9&  
int nThreadID; //Thread's ID C& +MRP  
boolean bDownOver = false; //Downing is over r[L%ap\{  
boolean bStop = false; //Stop identical `>:5[Y  
FileAccessI fileAccessI = null; //File Access interface ;}46Uc#WS  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xo"GNFh!  
{ ZLkl:'E_  
this.sURL = sURL; DK4yAR,g  
this.nStartPos = nStart; )O1
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this.nEndPos = nEnd; i1 E|lp)  
nThreadID = id; #aP#r4$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P>7Xbm,VP  
} x>#{C,Fi  
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public void run() &BVH
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{ ;'"'|} xn  
while(nStartPos < nEndPos && !bStop) vhrf89-q  
{ AWR :~{  
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try{ Q]k<Y  
URL url = new URL(sURL); B5lwQp]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); r6DLShP-Ur  
String sProperty = "bytes="+nStartPos+"-"; U zy@\  
httpConnection.setRequestProperty("RANGE",sProperty); MKHnA|uQ](  
Utility.log(sProperty); \<LCp;- K  
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InputStream input = httpConnection.getInputStream(); G]K1X"W?  
//logResponseHead(httpConnection); #I/P9)4  
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byte[] b = new byte[1024]; jRK}H*uem  
int nRead; Y6jyU1>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6j%%CWU{~  
{ %rW}x[M%w?  
nStartPos += fileAccessI.write(b,0,nRead); my'nDi  
//if(nThreadID == 1) 0j$\k|xFXZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gX}'b\zxC  
} e=sc$1|4=  
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Utility.log("Thread " + nThreadID + " is over!"); jl,gqMn"V  
bDownOver = true; /;`H )  
//nPos = fileAccessI.write (b,0,nRead); DzZF*ylQ5P  
} uF7vba$  
catch(Exception e){e.printStackTrace ();} =^9h z3j  
} W{6QvQD8  
} 7)rQf{q7  
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//打印回应的头信息 "-4|HA  
public void logResponseHead(HttpURLConnection con) _H
+]G"k/r  
{ H,7='n7"  
for(int i=1;;i++) "#d$$ 8  
{ 3lUVDNbZ  
String header=con.getHeaderFieldKey(i); Vk
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if(header!=null) Etz#+R&*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V6g*
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Utility.log(header+" : "+con.getHeaderField(header)); T^A(v(^D  
else y,D9O/VP  
break; U2VEFm6  
} (m/:B=K  
} JX59n%$@  
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public void splitterStop() (XZ[-M7  
{ GBz?$]6  
bStop = true; _J,**AZ~z  
} uo:RNokjJ  
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/J`}o}  
} mv9D{_,pD  
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/* )vtbA=RH?  
**FileAccess.java i~!g9o(  
*//文件访问(定位，写) yFE0a"0y  
package NetFox; Gs
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import java.io.*; 1 iH@vd  
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public class FileAccessI implements Serializable{ Jz8P':6[  
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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 `m 5\  
RandomAccessFile oSavedFile; Es=G' au  
long nPos; [@K'}\U^+  
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public FileAccessI() throws IOException 4 ]oe`yx  
{ x?i wtZ@  
this("",0); %JeNDXbI4  
} m(f`=+lqI`  
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public FileAccessI(String sName,long nPos) throws IOException 4MC]s~n  
{ 6~dAK3v5  
oSavedFile = new RandomAccessFile(sName,"rw"); O"\4[HE^  
this.nPos = nPos; S^s-m
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oSavedFile.seek(nPos); Ar%*NxX  
} M6-uTmN:d  
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public synchronized int write(byte[] b,int nStart,int nLen) U6JD^G=qR,  
{ ?V`-z#y7  
int n = -1; 3W'fEh5  
try{ ;MfqI/B{  
oSavedFile.write(b,nStart,nLen); |$ PA  
n = nLen; < F5VJ  
} _a&gbSQv  
catch(IOException e) &v:zS$m>  
{ rfDGS%!O%  
e.printStackTrace (); e N`+r  
} CI*Je
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return n; /
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} lBP?7`U  
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} L,zx\cj?z  
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/* ]ZLF=  
**SiteInfoBean.java O72g'qFPE  
*/ 5Sl"1HL  
package NetFox; -zECxHjx  
CH7a4qL`  
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public class SiteInfoBean { $NCvF'  
/l`zZ>  
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private String sSiteURL; //Site's URL 'v'[_(pq  
private String sFilePath; //Saved File's Path 6$"IeBRO  
private String sFileName; //Saved File's Name 1F.._5_"]  
private int nSplitter; //Count of Splited Downloading File 05F/&+V  
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public SiteInfoBean() aPJTH0u  
{//nSplitter的缺省值为5 t %u0=V  
//default value of nSplitter is 5 o?]Q&,tO  
this("","","",5); @<DRFP  
} :%sG'_d  
oDS7do  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A8ViJ  
{  +At[[  
sSiteURL= sURL; *6JA&zj0B  
sFilePath = sPath; 3MX#}_7A  
sFileName = sName; Z +/3rd  
this.nSplitter = nSpiltter; cRI2$|  
4+8)0;<H  
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} nZiwR4kM  
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public String getSSiteURL() HnPy";{  
{ KyIUz9$  
return sSiteURL; 4UbqYl3|a  
} P^o@x,V!&  
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54{E&QvL8o  
public void setSSiteURL(String value) UR'v;V&Cb\  
{ koB'Zp/FaY  
sSiteURL = value; 9T;>gm  
} RAa1^Qb  
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public String getSFilePath() Jd `Qa+  
{ U:x;4  
return sFilePath; NxJnU<g-  
} h_-4Q"fb(  
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public void setSFilePath(String value) ebEI%8p g  
{ .3) 27Cjw  
sFilePath = value; \e'Vsy>q  
} (Jb#'(~a  
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public String getSFileName() = y^5PjN  
{ o(}%b8 K  
return sFileName; C D6N8n]  
} 
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public void setSFileName(String value) {$t*XTY6R  
{ %1 RWF6  
sFileName = value; [PXq<ST  
} #P!<u Lc%  
Sg%s\p]N_#  
h[Sd3Z*  
public int getNSplitter() iWWt
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{ C-ORI}o  
return nSplitter; N, u]2,E  
} {oOUIP  
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public void setNSplitter(int nCount) ] 0L
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{ ZweAY.]e  
nSplitter = nCount; Ij
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}  &I-T  
} VZ IY=Q>g  
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/* iN[6}V6Sm  
**Utility.java K:9AP{+  
*/ IkmEctAU  
package NetFox; k|>yFc  
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public class Utility { 8wO4;  
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public Utility() a:GM|X  
{ Q
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} t+d7{&B  
|d~'X%b%  
//线程睡眠 vaQsG6q[  
public static void sleep(int nSecond) rF}Q(<Y86  
{ U<F|A!Fg  
try{ '>"blfix8  
Thread.sleep(nSecond); JXRU9`3)A  
} k$5l kP.  
catch(Exception e) Q)XH5C2X  
{ C}uzzG6s  
e.printStackTrace (); 4dN <B U  
} T)<^S(57  
} 96;5  
sk07|9nU  
//日志 O..{wdZy  
public static void log(String sMsg) ^AI02`c.  
{ *otgI"y\  
System.err.println(sMsg); H;<>uELie  
} `zq+Xl  
z{ M2tLNb  
K2Ro0  
public static void log(int sMsg) D=%1?8K  
{ <7)sS<I  
System.err.println(sMsg); H}_R`S  
} [%yj' )R/  
} 9%SC#V'  
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/* ~}{_/8'5  
**TestMethod.java PP\ bDEPy  
*/ !#%>,X#+  
package NetFox; ZXo;E  
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public class TestMethod { &RbPN^  
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{7DXSe4  
public TestMethod() wC%qSy'  
{ ///xx/weblogic60b2_win.exe y'b*Dk{  
try{ R|$b\3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iOZ#}"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \}4*}Lr  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \`z%5/@f;  
fileFetch.start(); 04}8x[t  
} )\D{5j  
catch(Exception e){e.printStackTrace ();} 2[(~_VJ  
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2
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} xR kw+  
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public static void main(String[] args) xDl; tFI  
{ &uc`w{,Zs  
new TestMethod(); N.q*jY=X|  
} !&b| [b  
} p/nATvh$  
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