http断点续传简单实现（java)

/* 6:`4bo  
**SiteFileFetch.java [g$
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*/ *4[P$k$7  
package NetFox; V_jGL<X|  
import java.io.*;  lLNI5C  
import java.net.*; $x(p:+TI\4  
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public class SiteFileFetch extends Thread { hGU 3DKHT  
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SiteInfoBean siteInfoBean = null; //文件信息Bean co>IJzg  
long[] nStartPos; //开始位置 (iY2d_FQ[  
long[] nEndPos; //结束位置 rnM C[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 QTjnXg?Ri  
long nFileLength; //文件长度 U]O>DM^'  
boolean bFirst = true; //是否第一次取文件 rh6 e  
boolean bStop = false; //停止标志 gmtS3,  
File tmpFile; //文件下载的临时信息 K,@} 'N  
DataOutputStream output; //输出到文件的输出流 F2dwT  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Nq[-.}Z6  
public SiteFileFetch(SiteInfoBean bean) throws IOException \N)!]jq  
{ cs)R8vuB)z  
siteInfoBean = bean; qDjH^f  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6Q}>=R^h  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;rt\  
if(tmpFile.exists ()) Y|-:z@n6C  
{ `6pz9j]  
bFirst = false; K,Hxe;-  
read_nPos(); 5YQJNP  
} lYy:A%yDT  
else .8]=yPm  
{ (O'O#AD  
nStartPos = new long[bean.getNSplitter()]; zz-X5PFn  
nEndPos = new long[bean.getNSplitter()]; 8n/[oDc]  
} <|VV8r93  
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} X92I==-w  
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public void run() Fhs/<w-  
{ q`HK4~i,  
//获得文件长度 $QaEU="Z  
//分割文件 S vW{1  
//实例FileSplitterFetch h`Xl~=
 
//启动FileSplitterFetch线程 BqDOo(%1)  
//等待子线程返回 `6{
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try{ >UV?nXP}  
if(bFirst) 0|]qWcD  
{ 2\G[U#~bi  
nFileLength = getFileSize(); r,wC5%&Za  
if(nFileLength == -1) Q-||A  
{ |O[ I=!  
System.err.println("File Length is not known!"); 0t)5KO  
} ]v0=jm5A  
else if(nFileLength == -2) 3OJGBiDAr  
{ k(_^Lq f-  
System.err.println("File is not access!"); }XRRM:B|)(  
} ?n
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else QMwV6cA  
{ h{CyYsQ  
for(int i=0;i<nStartPos.length;i++) CA,2&v"  
{ p}q]G
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); vJuL+'[i  
}  T_<:  
for(int i=0;i<nEndPos.length-1;i++) h]k1vp)Q y  
{ ^6 \@$  
nEndPos = nStartPos[i+1]; Uk4G9}I  
} y1Y  
nEndPos[nEndPos.length-1] = nFileLength; __ G=xf  
} M(W-\L  
} &M2fcw?  
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//启动子线程 Y2(,E e2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; M[^EHa<i  
for(int i=0;i<nStartPos.length;i++) ?1Uq ud  
{ )D ':bWP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gHVD,Jr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lF)k4 +M  
nStartPos,nEndPos,i); -@/!u9l  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r1.OLn?C  
fileSplitterFetch.start(); LO)p2[5#R  
} DC*6=m_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), EP8R[Q0_"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W! GUA<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Fj1'z5$  
nEndPos = " + nFileLength); Q6fPqEX=  
// fileSplitterFetch[nPos.length-1].start(); +$B#] ,  
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//等待子线程结束 v\Zq=,+  
//int count = 0; tdnd~WSR  
//是否结束while循环 (2r808^2  
boolean breakWhile = false; \7 }{\hY-  
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3 /LW6W|  
while(!bStop) 6?= ^8  
{ Tyw
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write_nPos(); g715+5z[  
Utility.sleep(500); ~0Mw\p%}  
breakWhile = true; _&PF(/w  
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for(int i=0;i<nStartPos.length;i++) T_~xDQ`v  
{ CMHg]la  
if(!fileSplitterFetch.bDownOver) =v~$&@  
{ @<44wMp  
breakWhile = false; Vet<,;Te  
break; Lq{/r+tt/  
} _"- ,ia[D  
} D~@lpcI  
if(breakWhile) Ir3|PehB  
break; \,yg@R  
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//count++; Px?0)^"2  
//if(count>4) WsR4)U/]v  
// siteStop(); -d6PXf5  
} ]0;,M  
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System.err.println("文件下载结束！"); #,rP1#?  
} K=!?gd!Vw  
catch(Exception e){e.printStackTrace ();} u1/q8'RW  
} 420cbD3a  
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//获得文件长度 qX*Xo[Xp  
public long getFileSize() ;Dc\[r  
{ mH!\]fmR~  
int nFileLength = -1; )|<g\>/  
try{ 10$:^  
URL url = new URL(siteInfoBean.getSSiteURL()); BHZSc(-o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I7jIA>ZZi  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'jBtBFzP-  
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int responseCode=httpConnection.getResponseCode(); $kn"S>jV  
if(responseCode>=400) #oEq)Vq>g|  
{ (eO_]<wmky  
processErrorCode(responseCode); q4ej7T8  
return -2; //-2 represent access is error @{x+ln1r  
} ;Yn_*M/*  
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String sHeader; @1)C3(=A  
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for(int i=1;;i++) luV_  
{ n_-k <
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y~I6ee,\  
//Utility.log(in.readLine()); =8x-+u5}rK  
sHeader=httpConnection.getHeaderFieldKey(i); P%Wl`NA P  
if(sHeader!=null) t}Kz
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{ " {Nw K  
if(sHeader.equals("Content-Length")) S{qn^\0  
{ "gq_^&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); qN6
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break; Oa-~}hN  
} rcG-Vf@  
} [
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else B-aJn8>/  
break; Axx{G~n![  
} Xe\,:~  
} kF7`R4Sz  
catch(IOException e){e.printStackTrace ();} j%E9@#  
catch(Exception e){e.printStackTrace ();} (r$QQO)/  
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Utility.log(nFileLength); 5fud:k  
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return nFileLength; T!gq Z  
} ^HNccr  
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//保存下载信息（文件指针位置） v*EErQML8b  
private void write_nPos() _@ @"'  
{ KS(Ms*k;'  
try{ Zj2tQ}N  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QNCG^ub  
output.writeInt(nStartPos.length); v@ OM  
for(int i=0;i<nStartPos.length;i++) _c6 zzGtH  
{ Lcy>!3q3~  
// output.writeLong(nPos); `jH0FJQ  
output.writeLong(fileSplitterFetch.nStartPos); wfc+E9E  
output.writeLong(fileSplitterFetch.nEndPos); r
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} }J\KnaKo  
output.close(); 8:t1%O$  
} i+B
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catch(IOException e){e.printStackTrace ();} !FJ_\UST0  
catch(Exception e){e.printStackTrace ();} Q4&<RWbT^  
} ^W
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//读取保存的下载信息（文件指针位置） /A/k13 J  
private void read_nPos() Q OP8{~O  
{ qVmG"et'J  
try{ iC\t@BVS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &|) (lX  
int nCount = input.readInt(); WJ(E3bb  
nStartPos = new long[nCount]; #ui7YUR=2  
nEndPos = new long[nCount]; ]e]l08  
for(int i=0;i<nStartPos.length;i++) v0S7 ]?_  
{ ShRkL<  
nStartPos = input.readLong(); ];G$~[  
nEndPos = input.readLong(); z3p#`  
}
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input.close(); B=J/HiwV)  
} Bc2PF;n  
catch(IOException e){e.printStackTrace ();} [P"R+$"   
catch(Exception e){e.printStackTrace ();} LjA>H>8%[  
} h;sdm/  

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private void processErrorCode(int nErrorCode) (_O_zu8_  
{ 9:jZ3U  
System.err.println("Error Code : " + nErrorCode); cE0Kvqe`  
} Ok2>%e  
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*FEY"W+bY  
//停止文件下载 ;R.l?Bg  
public void siteStop() #y%?A;  
{ LXQ-J  
bStop = true; JK9}Kb};  
for(int i=0;i<nStartPos.length;i++) YKs^aQm#  
fileSplitterFetch.splitterStop(); H&zhYKw  
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} ,zY!EHpx  
} Zf%6U[{ T  
//负责部分文件的抓取 -KG3_kE  
**FileSplitterFetch.java a7UfRG  
*/ )q+9_KUq  
package NetFox; O<v9i4*  
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import java.io.*; mf)o1O&B  
import java.net.*; (l3P<[[?  
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public class FileSplitterFetch extends Thread { kGSB6  
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String sURL; //File URL mMEa*9P  
long nStartPos; //File Snippet Start Position h^KLqPBt{  
long nEndPos; //File Snippet End Position e.IKmH]z  
int nThreadID; //Thread's ID =K2mR}n\;  
boolean bDownOver = false; //Downing is over #7A_p8  
boolean bStop = false; //Stop identical hup<U+p  
FileAccessI fileAccessI = null; //File Access interface zbDM+;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException icPg<>
TQ  
{ SlZ>N$E  
this.sURL = sURL; Qm X(s  
this.nStartPos = nStart; ~y(-
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this.nEndPos = nEnd; z2QZ;ZjvRS  
nThreadID = id; 3yfq*\_uXw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 a jCx"J  
} yS[Z%]bvU  
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public void run() VfiMR%i}  
{ NN9`jP2  
while(nStartPos < nEndPos && !bStop) e/;chMCq  
{ ^3L6mOoA  
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try{ ?>W4*8(  
URL url = new URL(sURL); 0#rv.rJ{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !be6}  
httpConnection.setRequestProperty("User-Agent","NetFox"); %?3\gFvBo  
String sProperty = "bytes="+nStartPos+"-"; cR1dGNcp/@  
httpConnection.setRequestProperty("RANGE",sProperty); 2I#4jy/g  
Utility.log(sProperty); f:h.O# d>  
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InputStream input = httpConnection.getInputStream(); w8Mi:;6  
//logResponseHead(httpConnection); mb\}F9  
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byte[] b = new byte[1024]; x^|J-
  
int nRead; YEWHr>&Z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) w-%
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{ ]r{-K63P{!  
nStartPos += fileAccessI.write(b,0,nRead); <z*SO a  
//if(nThreadID == 1) DVNGV   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #Pulbk8  
} l*|^mx^Q  
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Utility.log("Thread " + nThreadID + " is over!"); aNpeePF)z  
bDownOver = true; [*j C  
//nPos = fileAccessI.write (b,0,nRead); 6N&S3<c4JO  
} $GyO+xF  
catch(Exception e){e.printStackTrace ();} "bRg_]\q6  
} >Udb*76 D  
} ~R]E=/m|  
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//打印回应的头信息 tj ,*-).4%  
public void logResponseHead(HttpURLConnection con) Eg"DiI)7  
{ av(d0E}}b  
for(int i=1;;i++) D@yg)$;z  
{ VJX{2$L  
String header=con.getHeaderFieldKey(i); XB)e;R  
if(header!=null) gOI#$-L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `MgR/@%hr  
Utility.log(header+" : "+con.getHeaderField(header)); `CI9~h@k  
else \guZc}V]:\  
break; )*I=>v.Jq  
} %6}S'yL  
} j[XA"DZR<  
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public void splitterStop() {R7>-Y[4)2  
{ sD$ \!7:b  
bStop = true; ^A
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} 8{HeHU  
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} 6u3DxFiTm  
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/* @.gT&H
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**FileAccess.java UAT46  
*//文件访问(定位，写) _7YAF,@vT  
package NetFox; C|Bk'<MI  
import java.io.*; zYdSg<[^  
,9q=2V[GP  
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public class FileAccessI implements Serializable{ p3:x\P<|  
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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 fMr6ZmB  
RandomAccessFile oSavedFile; 0\g;^Zpi  
long nPos; e_+`%A+-  
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public FileAccessI() throws IOException hi>Ii2T  
{ e| (jv<~r  
this("",0); yUQ;tTI  
} GBvB0kC)c  
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public FileAccessI(String sName,long nPos) throws IOException lph3"a^  
{ %5*gsgeI  
oSavedFile = new RandomAccessFile(sName,"rw"); ](NSpU|*  
this.nPos = nPos; :tM|$TZ  
oSavedFile.seek(nPos); Z!C\n[R/  
} -Q;5A;sr2  
6rL'hB!!]*  
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public synchronized int write(byte[] b,int nStart,int nLen) Qp<?[C}'W  
{ TH/!z,(>  
int n = -1; &-+qB >SK>  
try{ 5oplV(<?*S  
oSavedFile.write(b,nStart,nLen); EuqmA7s8A  
n = nLen; ~)D2U:"^xm  
} 0\wMlV`F  
catch(IOException e) kf0zL3|  
{ VG+Yhm<SL  
e.printStackTrace (); B8 -/C\  
} ;u,%an<(  

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return n; 5Ga
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} \SnW(,`oX  
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} %,MCnu&Z  
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/^qCJp`  
/* skdSK7 n  
**SiteInfoBean.java pq*b"Jku1  
*/ fu9y3`  
package NetFox; ! 2"zz/N{  
h|dVVCsN  
jgYUS@}  
public class SiteInfoBean { p*W4^2(d  
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private String sSiteURL; //Site's URL ][:6En}  
private String sFilePath; //Saved File's Path _x z_D12  
private String sFileName; //Saved File's Name E3.=|]W'  
private int nSplitter; //Count of Splited Downloading File }f^r@3Cb3  
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9#/z[!  
public SiteInfoBean() <!K2xb-d^  
{//nSplitter的缺省值为5 b`E0tZcJ  
//default value of nSplitter is 5 gPe*M =iF  
this("","","",5); 0gHJ%m9s  
} w@.E}%bwq  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2j H`  
{ Tx0/3^\>8A  
sSiteURL= sURL; 17H_>a
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sFilePath = sPath; !li Q;R&  
sFileName = sName; :^3MN  
this.nSplitter = nSpiltter; 5h+g^{BE  
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} <X j:c2@  
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public String getSSiteURL() Lh"Je-x<<  
{ oj$D3  
return sSiteURL; W$B>O  
} 2y#4rl1Utx  
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public void setSSiteURL(String value) :doP66["!  
{ sBu=@8R]y  
sSiteURL = value; =iRc&  
} X82sw>Y  
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m=PSCIb  
public String getSFilePath() odny{ePAf  
{ `9s5 *;Z  
return sFilePath; rgB`<[:b  
} fa/ '4  
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public void setSFilePath(String value) Sq UoXNw  
{ K`j#'`/KC  
sFilePath = value; jbn{5af  
} Ngu+V  
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public String getSFileName() G#Nh)ff  
{ X
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return sFileName; =:1f 0QF  
} 3kdTteyy+  

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public void setSFileName(String value) *r?g&Vw$m  
{ 4NQS'*%D  
sFileName = value; E4HG`_cWb  
} u\ytiGO*  

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public int getNSplitter() V(=~p[  
{ N/8qd_:8  
return nSplitter; CP|N
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} "\vEi &C  
5sM-E>8G^{  
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public void setNSplitter(int nCount) Od^y&$|_%`  
{ SBAq,F'  
nSplitter = nCount; E6NkuBQ((  
} V~&P<=8;Wl  
} hh{4r} |  
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/* ]"q)X{G(+  
**Utility.java Q68&CO(rE  
*/
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package NetFox; 1V+a;-?  
v~?d7p{  
IW Lv$bPZ/  
public class Utility { tcwE.>5O  
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public Utility() n9050&_S  
{ ?<#6=  
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} {Lk~O)E  
,6}HAC $  
//线程睡眠 >+7+ gSD#:  
public static void sleep(int nSecond) d@b"tb}R  
{ 4G;+ETp  
try{ f%an<>j^w  
Thread.sleep(nSecond); G=jdb@V/?  
} WT;=K0W6&  
catch(Exception e) Qa5<go{  
{ 9 @!Og(l  
e.printStackTrace (); LU?X|{z  
} KY!  
} ]V6<h Psi  
Ib*l{cxN  
//日志 s!9.o_k  
public static void log(String sMsg) 14]!LgH  
{ !\}Dxt  
System.err.println(sMsg); ]~U4;  
} ]chcRc[!  
e/r41  
6$4G&'J  
public static void log(int sMsg) ^IjKT  
{ fYuJf,I[f  
System.err.println(sMsg); >O&(G0!N+}  
} * Od_Cl  
} k*J}/HO  
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>e/;  
/* Cj _Q9/  
**TestMethod.java ZK27^oG  
*/ `5r*4N<  
package NetFox; H\Y.l,^  
);kO27dg  
7Z0 )k9*  
public class TestMethod { qy`@\)S/5  
o*_[3{FU  
H2BD5  
public TestMethod() X)e6Y{vO  
{ ///xx/weblogic60b2_win.exe }9/30  
try{ `l9Pk\X[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); s_hf,QH  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _UT>,c;h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Dq)V]
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fileFetch.start(); @g }r*U?  
} *Y?rls`  
catch(Exception e){e.printStackTrace ();} <T)9mJYr  
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-m(9*b{h@  
} L~"~C(g  
'\(Us^Ug  
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public static void main(String[] args) Pz,kSxe=  
{ =<YG0K  
new TestMethod(); 2o] V q  
} .>zXz%p  
} _VMW-trG
 
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