http断点续传简单实现（java)

/* wZjlHe  
**SiteFileFetch.java z$|;-u|  
*/ B52yaG8C  
package NetFox; @TysXx  
import java.io.*; )\>r-g$  
import java.net.*; b0 &  
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public class SiteFileFetch extends Thread { =p q:m  
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SiteInfoBean siteInfoBean = null; //文件信息Bean hk_g2g  
long[] nStartPos; //开始位置 oSY7IIf%L  
long[] nEndPos; //结束位置 F}'wH-qp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X'x3esw w  
long nFileLength; //文件长度 v5T`K=qC  
boolean bFirst = true; //是否第一次取文件 \,R!S/R#  
boolean bStop = false; //停止标志 MU1E_"Z)  
File tmpFile; //文件下载的临时信息 F;P5D<  
DataOutputStream output; //输出到文件的输出流 -IU4#s  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BxdX WO  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?ok)>P  
{ eLV.qLBUs  
siteInfoBean = bean; > H BJk:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s]Gd-
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .*Vkua  
if(tmpFile.exists ()) B`{mdjMy  
{ ZVL gK}s
 
bFirst = false; >aG=T{  
read_nPos(); WL U}  
} PO o%^'(  
else < bFy(+  
{ 2n)gpLIJ  
nStartPos = new long[bean.getNSplitter()]; d)tiO2W  
nEndPos = new long[bean.getNSplitter()]; Qdu$Os  
} |9IC/C!HC  
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} vk'rA{x  
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public void run() #!})3_Qc(y  
{ ^=+e?F`:
{  
//获得文件长度 YJ,*(A18  
//分割文件 }G'XkoI&  
//实例FileSplitterFetch ubbnFE&PD  
//启动FileSplitterFetch线程 G;s"h%Xw98  
//等待子线程返回 O~PChUU*Y  
try{ 0Z HDBh  
if(bFirst) f*m[|0qI<X  
{ /e1(? 20  
nFileLength = getFileSize(); Y:psZ  
if(nFileLength == -1) ()\jCNLT  
{ ~
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System.err.println("File Length is not known!"); rF] +,4  
} | -+zofx  
else if(nFileLength == -2) H)>sTST(  
{ f%XJ;y\,9H  
System.err.println("File is not access!"); c}-(.eu  
} P!e=b-T  
else m Ni2b*k  
{ 6kR\xP]Kr  
for(int i=0;i<nStartPos.length;i++) SK R1E];4  
{ #jA)>z\Q^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1e}8LH7  
} 0<.RA%dj  
for(int i=0;i<nEndPos.length-1;i++) o
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{ .Djta|puu  
nEndPos = nStartPos[i+1]; sg
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} zN!j%T.e  
nEndPos[nEndPos.length-1] = nFileLength; BStk&b  
} Qxa{UQh}9  
} D4Etl5k  
(=c1  
N3%*7{X 9  
//启动子线程 q0./O|Dj   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E[g*O5  
for(int i=0;i<nStartPos.length;i++) FTf<c0  
{ P^)q=A8Z#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4kl Ao$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), X`JVR"=4  
nStartPos,nEndPos,i); ?*u*de[,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S6D^3n  
fileSplitterFetch.start(); gl7|H&&xV  
} }]6f+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f p[,C1U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qCPmbg  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rHz||jjU  
nEndPos = " + nFileLength); yI3kvh  
// fileSplitterFetch[nPos.length-1].start(); BRv x[u  
T .n4TmF  
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//等待子线程结束 ynwG\V  
//int count = 0; rs;r $  
//是否结束while循环  P_Hv%g  
boolean breakWhile = false; ig!7BxM)<h  
)rtomp:X  
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while(!bStop) 1G^#q,%X_v  
{ GJA`l8`SQ  
write_nPos(); cg{AMeW  
Utility.sleep(500); Log|%P\  
breakWhile = true; S\#17.=  
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for(int i=0;i<nStartPos.length;i++) SA"8!soY3  
{ J'T=q/  
if(!fileSplitterFetch.bDownOver) ;zH HIdQ>-  
{  Mps5Vv  
breakWhile = false; =^;P#kX  
break; 5h{`<W  
} +-$Ko fnM  
} h6D^G5i  
if(breakWhile) BS1A
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break; B.dT)@Lx0  
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//count++; </`yd2>
 
//if(count>4) 7'lZg<z{~j  
// siteStop(); 2kh"8oQ  
} m#7*:i&@Y  
}6u2*(TmD  
8|^CK|m6*  
System.err.println("文件下载结束！"); (eWPis[  
} 23]Y<->Eu<  
catch(Exception e){e.printStackTrace ();} OFU/gaO~  
} {KL5GowH  
, X{>  
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//获得文件长度 sW@krBxMv  
public long getFileSize() 6<7
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{ ~NcQ1.  
int nFileLength = -1; Kg\R+i@#<  
try{ K }$&:nao  
URL url = new URL(siteInfoBean.getSSiteURL()); yYZxLJ='  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x.mrCJn)  
httpConnection.setRequestProperty("User-Agent","NetFox"); cmwPu
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int responseCode=httpConnection.getResponseCode(); 1fU,5+PH  
if(responseCode>=400) dtt~ Bd  
{ cC{"<fYF  
processErrorCode(responseCode); 0%`4px4J  
return -2; //-2 represent access is error RO(TvZ0pE  
} D<$Xy
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String sHeader; ay )/q5  
i5}
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5
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for(int i=1;;i++)
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{ "2ru7Y"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ne}+E  
//Utility.log(in.readLine()); oXsL9,  
sHeader=httpConnection.getHeaderFieldKey(i); Dh4 6o|P  
if(sHeader!=null) 8 .>/6M  
{ iUk-'   
if(sHeader.equals("Content-Length")) _i0kc,*C\  
{ _l`e#XbG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); X;F8_+Np  
break; I^\&y(LJF  
} 08bJCH  
} R"v 3!P  
else nAJdr*`a,5  
break; V N{NA+I  
} h&&6r\4/|  
} 1Tp/MV/>  
catch(IOException e){e.printStackTrace ();} $g9**b@  
catch(Exception e){e.printStackTrace ();} k;W@LfP  
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Utility.log(nFileLength); & WOiik  
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return nFileLength; VSX@e|Nj  
} K6JVg$  
] ]U<UJ  
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//保存下载信息（文件指针位置） CBYX]  
private void write_nPos() PQmq5N6  
{ $lA V6I.  
try{ rf:XRJ<4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); VXBY8;+Yp  
output.writeInt(nStartPos.length); pO  Iq%0]  
for(int i=0;i<nStartPos.length;i++) _n8GWBi  
{ m><w0k?t  
// output.writeLong(nPos); N7r_77%m0  
output.writeLong(fileSplitterFetch.nStartPos); `$LWmm#  
output.writeLong(fileSplitterFetch.nEndPos); 6DIZ@oi  
} ~5 N)f UI\  
output.close(); -/C)l)V}  
} T VmH  
catch(IOException e){e.printStackTrace ();} ^[E'1$D  
catch(Exception e){e.printStackTrace ();} lT&wOm3  
} LWoG4s?w  
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//读取保存的下载信息（文件指针位置） Jq.lT(E8D  
private void read_nPos() O=cxNy-I  
{ ,fDEz9-,  
try{ `^JJ&)4iv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4BYE1fUzd  
int nCount = input.readInt(); EI>6Nh  
nStartPos = new long[nCount]; \`V$ 'B{.  
nEndPos = new long[nCount]; '7Nr8D4L  
for(int i=0;i<nStartPos.length;i++) Cb t{H}I3  
{ '+>fFM,*B  
nStartPos = input.readLong(); F7L&=K$2y  
nEndPos = input.readLong(); 7M_U2cd|TD  
} gbeghLP[?  
input.close(); YpAg  
} |'ln?D:&  
catch(IOException e){e.printStackTrace ();} 8b.u'r174  
catch(Exception e){e.printStackTrace ();} WW2Ob*  
} ?<&O0'Q  
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private void processErrorCode(int nErrorCode) yq-=],h  
{ 5RH2"*8T  
System.err.println("Error Code : " + nErrorCode); >Iewx G
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} =\#%j|9N9  
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0_P}z3(M  
//停止文件下载 1be %G [*  
public void siteStop() 1axQ)},o@p  
{ Ab%;Z5$fr  
bStop = true; jCAC `  
for(int i=0;i<nStartPos.length;i++) 4(neKr5\#  
fileSplitterFetch.splitterStop(); =p^He!  
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} YIt& >  
} jc[_I&Oc_  
//负责部分文件的抓取 8[CB>-9  
**FileSplitterFetch.java $8USyGi3J  
*/ m=AqV
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package NetFox; *%w69#D  
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import java.io.*; UX3BeUi.)  
import java.net.*; ;@,Q&B2eM  
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public class FileSplitterFetch extends Thread { CM)Q&:  
g*)K/Z0pJ$  
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String sURL; //File URL tkQH\5  
long nStartPos; //File Snippet Start Position =~Ynz7 /x  
long nEndPos; //File Snippet End Position )#a[-.OI  
int nThreadID; //Thread's ID JXG"M#{  
boolean bDownOver = false; //Downing is over &zQ2M#{82  
boolean bStop = false; //Stop identical Cz4)Yz  
FileAccessI fileAccessI = null; //File Access interface `b8v1Os^2  
+')f6P;t>=  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y={&5Mir  
{ RjF'x  
this.sURL = sURL; QIN."&qC^  
this.nStartPos = nStart; ri`R<l8  
this.nEndPos = nEnd; $@d9<83=  
nThreadID = id; g-`~eG28D5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -[= drj9I  
} MS(JR  
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public void run() %p^.\ch9  
{ >e2<!#er|  
while(nStartPos < nEndPos && !bStop) Eca\fkj  
{  $Y=T&O  
:+{ ?  
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try{ ZT02"3F  
URL url = new URL(sURL); V._6=ZJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "G-1>:   
httpConnection.setRequestProperty("User-Agent","NetFox"); aK,z}l(N  
String sProperty = "bytes="+nStartPos+"-"; +,o0-L1D  
httpConnection.setRequestProperty("RANGE",sProperty); <9=9b_z  
Utility.log(sProperty); {QBB^px  
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InputStream input = httpConnection.getInputStream(); i{!
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//logResponseHead(httpConnection); xD&^j$Em  
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byte[] b = new byte[1024]; nf1#tlIJd  
int nRead; >FhK#*Pa  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,f}UGd[a  
{ i>EgG5iJ  
nStartPos += fileAccessI.write(b,0,nRead); 7NC=*A~  
//if(nThreadID == 1) < B_Vc:Q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9ukg}_Hx  
} D+~_TA  

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Utility.log("Thread " + nThreadID + " is over!"); J--m[X  
bDownOver = true; Ggh.dZI4  
//nPos = fileAccessI.write (b,0,nRead); MYBx&]!\  
} g}laG8  
catch(Exception e){e.printStackTrace ();} st"{M\.p  
} Oz|K8p  
} b
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//打印回应的头信息 Ngb(F84H?  
public void logResponseHead(HttpURLConnection con) v+jsC`m  
{ KXV[OF&J  
for(int i=1;;i++) IHgeQ F ~  
{ *lef=:&,,  
String header=con.getHeaderFieldKey(i); 5XuT={o  
if(header!=null) ,>t69 Ad  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); C^QtSha
 
Utility.log(header+" : "+con.getHeaderField(header)); ,!V]jP)  
else K1V#cB WO  
break; {;2vmx9  
} ]"c+sMW  
} h^ -.]Y  
2+Px'U\  
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public void splitterStop() !*2%"H*  
{ dd?x(,"A`  
bStop = true; 0y&I/2  
} 8/z3=O&  

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} T#pk]c6Q  
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/* 7bxA]s{m  
**FileAccess.java \A
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*//文件访问(定位，写) gyS+9)gY  
package NetFox; X(jVRr_m9  
import java.io.*; /ywD{*  
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public class FileAccessI implements Serializable{ kE TT4U  
n.hv!W0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 M MzGd:0b  
RandomAccessFile oSavedFile; H3{GmV8  
long nPos; l!#m&'16"  
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public FileAccessI() throws IOException Tz2-Bp]h  
{ X7L8h'(@  
this("",0); cI]WrI2CQa  
} <o2r~E0r3  
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public FileAccessI(String sName,long nPos) throws IOException x.1-)\  
{ !ZDzEP*  
oSavedFile = new RandomAccessFile(sName,"rw"); m\/ Tj0e  
this.nPos = nPos; :S$l"wrh\  
oSavedFile.seek(nPos); a?yMHb{F  
} yT{8d.Rh  
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public synchronized int write(byte[] b,int nStart,int nLen) b;|55Y  
{ KYJjwXT28W  
int n = -1; ~)?  
try{ fjnTe  
oSavedFile.write(b,nStart,nLen); `[zQf  
n = nLen; :Q+5,v-c  
} I ];M7  
catch(IOException e) ylKmj
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{ 9+,R`v  
e.printStackTrace (); t6c<kIQ:-O  
} [P|[vWO  
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return n; 8Ry7
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} 5>6PH+Oq  
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} ?=GXqbS"  
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/* 6.t',LTB  
**SiteInfoBean.java I2(zxq&2M\  
*/ :a:[.  
package NetFox; iVB^,KQ@  
V8=Y@T,  
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public class SiteInfoBean { QrApxiw  
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private String sSiteURL; //Site's URL Z -%(~  
private String sFilePath; //Saved File's Path 61U<5:#l  
private String sFileName; //Saved File's Name Cw5%\K$=  
private int nSplitter; //Count of Splited Downloading File ,mPnQ?  
*M7E#bQ5B  
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public SiteInfoBean()
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{//nSplitter的缺省值为5 `ovtHl3Q  
//default value of nSplitter is 5 [nxE)D  
this("","","",5); P?BGBbC  
} {f9{8-W<u  
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j
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7\o!HMfK  
{ k\Q,h75  
sSiteURL= sURL; d@mo!zu  
sFilePath = sPath; 2A4FaBq"  
sFileName = sName; 2?@j~I=s2h  
this.nSplitter = nSpiltter; &Bx J  
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OT %nrzP  
} 1Xy]D  
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public String getSSiteURL() AvR2_  
{ _<ut)G^9  
return sSiteURL; g%[n4  
} %}2@rLP  
4^6.~6a  
7dihVvL $  
public void setSSiteURL(String value) QbhW!9(,  
{ H* !EP  
sSiteURL = value; %/kyT%1  
} [fu!AIQ
s  
3#wcKv%>&_  
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public String getSFilePath() gPS&^EdxA  
{ M8w5Ob  
return sFilePath; PIcrA2ll  
} 2EQ6J  
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public void setSFilePath(String value) .AV)'j#6P  
{ a:SQ16_?  
sFilePath = value;  Z:2I/  
} 33:DH}
  
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public String getSFileName() %u?HF4S'  
{ Gt9wR  
return sFileName; ^SEdA=!  
} eT"Uxhs-}  
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4n 3Tp{Y}  
public void setSFileName(String value) x}fn'iUnm  
{ OLq 0V
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sFileName = value; B68H&h]D#'  
} 4{9d#[KW  
>5~7u\#9  
!- C'}  
public int getNSplitter() b hjZ7=  
{ yI:# |w|  
return nSplitter; lD;'tqaC  
} F-n"^.7  
e^).W3SK]  
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public void setNSplitter(int nCount) @-.? B  
{ 5,+\`!g  
nSplitter = nCount; )J/HkOj"V  
} uMXc0fs!$  
} .uZ
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/* bv?0.{Z  
**Utility.java OVoO6F]  
*/ L^9HH)Jc  
package NetFox; >AD=31lq  
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public class Utility { V7CoZnz  

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public Utility() #S QXTR  
{ 5#:pT  
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} 7r{qJ7$%  
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//线程睡眠 _[Gb)/@mM  
public static void sleep(int nSecond) '|K.k6  
{ ka7uK][  
try{ e]W0xC-  
Thread.sleep(nSecond); ?z`MPdO  
} 2@@l{Y0f6  
catch(Exception e) jThbeY[  
{ .e[Tu|qo  
e.printStackTrace (); mE$dO3  
} ryD%i"g<  
} K\=8eg93Z  
-R+zeu(e'  
//日志 ;'kI/(;;C  
public static void log(String sMsg) \4~AI=aw,T  
{ HR{s&ho  
System.err.println(sMsg); 6o}V@UzqV  
} #0y<a:}R  
c cG['7  
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public static void log(int sMsg) )y50Mb0+  
{ &H;8QZ8uw  
System.err.println(sMsg); `bgb*Yaod  
} ;i)KHj'  
} 2/Nq'  
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%  
9{J?H
Fw*;  
/* w$Ux?y-L  
**TestMethod.java to3?$-L  
*/ aPIr_7e  
package NetFox; L4974E?S  
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public class TestMethod { 1t~({Pl<>  
cK}Pf+r>  
a+(j?_FyI  
public TestMethod() ?iSGH'[u  
{ ///xx/weblogic60b2_win.exe r%MyR8'k]  
try{ R$0U<(/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?vbDB4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); r
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SiteFileFetch fileFetch = new SiteFileFetch(bean); ;w6s<a@Zh  
fileFetch.start(); d.}}s$Q  
} jn=ug42d  
catch(Exception e){e.printStackTrace ();} iz x[  
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} b~wKF0vq  
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public static void main(String[] args) fEiJ~&{&  
{ _Xh=&(/8@  
new TestMethod(); sco uO$
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} _"f<Ol[!  
} <q6`~F~|  
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