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http断点续传简单实现(java)

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/* 2EeWcTBU}.  
**SiteFileFetch.java :(,Eq?  
*/ GHMoT  
package NetFox; g2=5IU<  
import java.io.*; (]|rxmycA  
import java.net.*; p2|BbC\N  
kQR kby  
Q1G?e,Q  
public class SiteFileFetch extends Thread { 3q=A35*LT>  
MSm vQ  
C} #:<Jx  
SiteInfoBean siteInfoBean = null; //文件信息Bean SnF3I  
long[] nStartPos; //开始位置 #-9;Hn4x  
long[] nEndPos; //结束位置 ])= k";76  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /"t*gN=wrF  
long nFileLength; //文件长度 pcM'j#;  
boolean bFirst = true; //是否第一次取文件 <t{T]i+  
boolean bStop = false; //停止标志 <y(uu(c  
File tmpFile; //文件下载的临时信息 NXv u}&H  
DataOutputStream output; //输出到文件的输出流 eD0Rv0BV^  
> Xq:?}-m2  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `}s$cgEG  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1*eWo~G  
{ (;o,t?:d  
siteInfoBean = bean; 4#?Ox vH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); N#')Qz:P  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;as4EqiK  
if(tmpFile.exists ()) llbj-9OZL  
{ jXO*_R  
bFirst = false; vj I>TIy  
read_nPos(); *`:zSnu  
} DRLX0Ml]\  
else 2\ /(!n  
{ fiSc\C~  
nStartPos = new long[bean.getNSplitter()]; A f@IsCOJ  
nEndPos = new long[bean.getNSplitter()]; VJMn5v[V  
} $cri"G  
JJ3(0 +  
.y{qsL^P  
iHo2=Cz  
} 5 N(/K.^  
!2WRxM  
8|A*N< h  
public void run() uE~? 2G  
{ [X.sCl|  
//获得文件长度 %+iJpRK)7  
//分割文件 A]2zK?|s  
//实例FileSplitterFetch 4/$ $?w4  
//启动FileSplitterFetch线程 Oslbt8)U6  
//等待子线程返回 e,qc7BJzK  
try{ Nhv~f0  
if(bFirst) o$>A;<  
{ Int 6xoz  
nFileLength = getFileSize(); RsS?ibozl  
if(nFileLength == -1) s@C@q(i6  
{ $-m`LF@  
System.err.println("File Length is not known!"); 83UIH0(  
} 0n S69tH  
else if(nFileLength == -2) 4r!8_$fN?G  
{ w%Tcx^:  
System.err.println("File is not access!"); _e AZ_@  
} mh>)N"  
else Mg]q^T.a  
{ 08&DP^NS  
for(int i=0;i<nStartPos.length;i++) '{j.5~4y  
{ w{3 B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eN@V?G26K  
} @cNX\$J  
for(int i=0;i<nEndPos.length-1;i++) 8Letpygm  
{ 89:Ys=  
nEndPos = nStartPos[i+1]; XM$r,}B k  
} +2=N#LM  
nEndPos[nEndPos.length-1] = nFileLength; U]lXw+&  
} <4,>`#NEo  
} _8b)Xx@5  
WC,&p  
0t<]Uf  
//启动子线程 7vRJQe)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bNR}Mk]?  
for(int i=0;i<nStartPos.length;i++) 4A:@+n%3m  
{ s{#ZRmc2B  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *Z=K9y,IC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), =CEQYk-y1  
nStartPos,nEndPos,i); s.]7c CY  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }wrZP}zM>  
fileSplitterFetch.start(); bS _!KU  
} LUv>0G#L[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G<,@|6"w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,p/iN9+Z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", /w{DyHT  
nEndPos = " + nFileLength); pb_+_(/c  
// fileSplitterFetch[nPos.length-1].start(); {~ ZSqd  
P]-d (N}/H  
Me[T=Tt`@w  
//等待子线程结束 -J4?Km  
//int count = 0; a9qB8/Gg[  
//是否结束while循环 O.e^? ysp/  
boolean breakWhile = false; 8'?V5.6?|~  
iy Zs:4jkc  
Asicf{HaX  
while(!bStop) _H(m4~ M  
{ A@#9X'C$^  
write_nPos(); d paZ6g  
Utility.sleep(500); K~OfC  
breakWhile = true; )Ac+5bs  
Z3Os9X9p  
8SK}#44Xz  
for(int i=0;i<nStartPos.length;i++) O/$pT%D1x  
{ hN$6Kx>{  
if(!fileSplitterFetch.bDownOver) w}^z1n  
{ .Y[sQO~%  
breakWhile = false; #>dfP"}&,  
break; 9'C kV[  
} 72@raA#y  
} 6W."h PP  
if(breakWhile) q[1:h  
break; QN:gSS{30  
aPaGnP:^  
2628 c`  
//count++; fQc2K|V  
//if(count>4) VYI%U'9Q  
// siteStop(); @$z/=gsy  
} ]0.? 1se  
{;]:}nA  
pzmm cjEC  
System.err.println("文件下载结束!"); &Al9%W  
} _@jBz"aq\  
catch(Exception e){e.printStackTrace ();} Dp!3uR ']p  
} 6b4Kcl<i  
t=J\zyX!  
My0h9'K  
//获得文件长度 !fr /WxJ  
public long getFileSize() 1BUdl=o>S  
{ z|[#6X6tT  
int nFileLength = -1; ,$@nbS{Q]  
try{ !xyO  
URL url = new URL(siteInfoBean.getSSiteURL()); j7=I!<w V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5*~Mv<#  
httpConnection.setRequestProperty("User-Agent","NetFox"); G^]T  
=cE:,z ;g  
t QkEJ pj  
int responseCode=httpConnection.getResponseCode(); WJCEiH  
if(responseCode>=400) ^:W.R7|  
{ ]YYjXg}%  
processErrorCode(responseCode); Xm&L@2V  
return -2; //-2 represent access is error _S5\5[^  
} [,)yc/{*  
) \Mwv&k1  
IE!fNuR4  
String sHeader; 3 G/#OJ  
cMOvM0f  
2GQ q(_  
for(int i=1;;i++) #<|5<U  
{ FLdO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); " ,&#9  
//Utility.log(in.readLine()); h"/FqO  
sHeader=httpConnection.getHeaderFieldKey(i); P]gksts9f.  
if(sHeader!=null) ~Fv&z'R  
{ sL|lfc'bB  
if(sHeader.equals("Content-Length")) "f\2/4EIl  
{ =\.Oc+p4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Cr|v3Y#h'  
break; t] LCe\#  
} ;mH1J'.(a  
} 50% |9D0?Y  
else T">-%-t  
break; uP/PVoKQ  
} ?F'gh4  
} CZyOAoc<  
catch(IOException e){e.printStackTrace ();} ;V]EF  
catch(Exception e){e.printStackTrace ();} D7cOEL<  
o8\@R  
J&UFP{)  
Utility.log(nFileLength); =t1.j=oC  
LcCb[r  
.kh%66:  
return nFileLength; L'=2Uk#.D  
} T5_z^ 7d  
%\PnsnJ9Q  
(x,w/1  
//保存下载信息(文件指针位置) $+P9@Q$  
private void write_nPos() %J4]T35^2  
{ yo*c& >  
try{ P lJl#-BO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |VM c,_D  
output.writeInt(nStartPos.length); ^ a%U *>P  
for(int i=0;i<nStartPos.length;i++) opTDW)  
{ FSv')`}  
// output.writeLong(nPos); :Z(?Ct&8  
output.writeLong(fileSplitterFetch.nStartPos);  9],;i7c  
output.writeLong(fileSplitterFetch.nEndPos); =$601r  
} h+F@apUS  
output.close(); ;;'b;,/  
} :/fG %e  
catch(IOException e){e.printStackTrace ();} -e7|DXj  
catch(Exception e){e.printStackTrace ();} Vt{C80n&N  
} Xm`s=5%  
+4^XFPq~  
`EVTlq@<  
//读取保存的下载信息(文件指针位置) eIc~J!?<&V  
private void read_nPos() F4X/ )$Dk  
{ _.0c~\VA  
try{ 6W$ #`N>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bep}|8,#u  
int nCount = input.readInt(); v<bq1QG  
nStartPos = new long[nCount]; *0M#{HQ  
nEndPos = new long[nCount]; jQ.]m   
for(int i=0;i<nStartPos.length;i++) ie+&@u  
{ EB jiSQw  
nStartPos = input.readLong(); Z'dY,<@  
nEndPos = input.readLong(); vc o/h  
} Y'"2s~_ Z  
input.close(); K[)N/Q  
} K0 .f4 o  
catch(IOException e){e.printStackTrace ();} cAC2Xq  
catch(Exception e){e.printStackTrace ();} o+{}O_r  
} Z y@35;r  
L^rtypkJ  
, M$*c  
private void processErrorCode(int nErrorCode) ^qqP):0y1V  
{ ;>[).fX>/  
System.err.println("Error Code : " + nErrorCode); j~c7nWfX  
} jzV*V<  
{"8\~r&b  
m3XL;1y:a  
//停止文件下载 I$0`U;Xd  
public void siteStop() {OP-9P=p  
{ t+Mr1e  
bStop = true; yAtM|:qq  
for(int i=0;i<nStartPos.length;i++) C3-l(N1O{  
fileSplitterFetch.splitterStop(); At%g^  
I=&5mg=m  
A@*P4E`xp  
} 8h9t8?  
} xtf]U:c  
//负责部分文件的抓取 evsH>hE^  
**FileSplitterFetch.java d+~c$(M)  
*/ uoFH{.)  
package NetFox; 'GQ1;9A57  
>`= '~y8  
< 'op  
import java.io.*; AC,$(E  
import java.net.*; Vi`+2%4  
vrn I Eur  
7>xxur&  
public class FileSplitterFetch extends Thread { '[JrP<~^o  
=%Gecj  
C.@R#a'  
String sURL; //File URL ]g3&gw  
long nStartPos; //File Snippet Start Position I%%\;Dy  
long nEndPos; //File Snippet End Position W-=~Afy  
int nThreadID; //Thread's ID liFNJd`|o+  
boolean bDownOver = false; //Downing is over l3n* b6  
boolean bStop = false; //Stop identical qfE/,L(B  
FileAccessI fileAccessI = null; //File Access interface f[ GH  
AM##:4   
^mFuZ~g;?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException hU5[k/ q  
{ Z<En3^j`  
this.sURL = sURL; 1 Y@6oT  
this.nStartPos = nStart; ih2H~c>O  
this.nEndPos = nEnd; U/,`xA;v>  
nThreadID = id; +OK.[ji?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h0 Acpd2  
} >!A&@1[M  
/7|u2!#Ui  
td q;D  
public void run() ?nrd$,  
{ X55Eemg/  
while(nStartPos < nEndPos && !bStop) aMuc]Wy#  
{ N<Rb<p%  
x '3<F  
Kr=DoQ."d8  
try{ 9g >]m 6  
URL url = new URL(sURL); 3nd02:GF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;M8N%  
httpConnection.setRequestProperty("User-Agent","NetFox"); QV+('  
String sProperty = "bytes="+nStartPos+"-"; HoymGU`w  
httpConnection.setRequestProperty("RANGE",sProperty); Nol',^)  
Utility.log(sProperty); FOB9CsMe  
1 dz&J\|E#  
C5i]n? )S  
InputStream input = httpConnection.getInputStream(); "vH@b_>9|  
//logResponseHead(httpConnection); go6Hb>  
Gw!jYnU  
k<"ZNQm$.  
byte[] b = new byte[1024]; EU ThH.  
int nRead; cG?RisSZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) en!cu_]t  
{ ,V)yOLApVj  
nStartPos += fileAccessI.write(b,0,nRead); RK/SeS  
//if(nThreadID == 1) ^qiTO`lg  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -}2q-  
} x_v pds  
gO<>L0,j  
`*9W{|~Gwx  
Utility.log("Thread " + nThreadID + " is over!"); BI;in;Ln  
bDownOver = true; j!&g:{ e  
//nPos = fileAccessI.write (b,0,nRead); q{ @>2AlK  
} hc>hNC:a  
catch(Exception e){e.printStackTrace ();} V5K`TC^  
} ?.|qRzWL  
} W=mh*G3y  
fcr\XCG7U  
fbNVmjb$)  
//打印回应的头信息 ," :ADO-  
public void logResponseHead(HttpURLConnection con) !s\-i6S>  
{ vwZ2kk!|i  
for(int i=1;;i++) \M=" R-&b  
{ jFw?Ky2  
String header=con.getHeaderFieldKey(i); 0u QqPF t  
if(header!=null) p:k>!8.Qho  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); h:" <x$F  
Utility.log(header+" : "+con.getHeaderField(header)); .2!'6;K  
else ff?:_q+.N  
break;  s4;SA  
} ?5'UrqYSW  
} cQu1WgQ G  
Th`IpxV  
U|u v SJ)X  
public void splitterStop() h?bm1e5kE  
{ F_zs"ex/  
bStop = true; GasIOPzK  
} @4T+0&OI10  
0#G&8*FMN  
8D)*~C'85E  
} KxGK`'E'r  
_&.CI6  
j?g{*M  
/* '2/48j X5  
**FileAccess.java @wYuc{%S  
*//文件访问(定位,写) Z99%uI3  
package NetFox; p/cVQ  
import java.io.*; {#zJx(2yG  
OY51~#BF  
N#6&t8;kTC  
public class FileAccessI implements Serializable{ 3vHEPm]  
+<Uc42i7n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 .AWRe1?  
RandomAccessFile oSavedFile; hR[Qdu6r  
long nPos; 9-Qu b+0o  
wP+wA}SN  
/"~CWNa  
public FileAccessI() throws IOException  z4&|~-m,  
{ o\g",O4-  
this("",0); }PK8[N  
} 3E+u)f lmB  
"So+  
z./u;/:  
public FileAccessI(String sName,long nPos) throws IOException G3OqRH  
{ `V$i*{c:#  
oSavedFile = new RandomAccessFile(sName,"rw"); D5]T.8kX(7  
this.nPos = nPos; +K; X$kB  
oSavedFile.seek(nPos); ]gQgNn?  
} rts@1JY[  
AHIk7[w  
@L=xY[&{  
public synchronized int write(byte[] b,int nStart,int nLen) QApil  
{ e#0R9+"Ba  
int n = -1; 4@4$kro  
try{ Qg%B<3 <  
oSavedFile.write(b,nStart,nLen); 3EI$tP@4  
n = nLen; Z '/:  
} MJt?^G (w?  
catch(IOException e) b=wc-n A  
{ mKvk6OC  
e.printStackTrace (); #:v|/2   
} &+xNR2";  
{Ymn_   
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return n; 8)\ ?6C  
} 1Vp['&  
4@.qM6 \\q  
H CZ#7Z  
} xeIt7b?#  
O< v0{z09*  
{<v?Z_!68  
/* GASDkVoij  
**SiteInfoBean.java gH,^XZe  
*/ f2`[skNj  
package NetFox; O8w R#(/  
G yvEc3|@  
}Cvf[H1+  
public class SiteInfoBean { %|I~8>m  
YiTiJ9jf  
^|5vmI'E  
private String sSiteURL; //Site's URL LS}u6\(  
private String sFilePath; //Saved File's Path k^w!|%a[  
private String sFileName; //Saved File's Name 9G[!"eZ}  
private int nSplitter; //Count of Splited Downloading File {dH87 nt  
P6!c-\  
9f\Lon4lX  
public SiteInfoBean() *Ew`Fm H  
{//nSplitter的缺省值为5 t3}>5cAxy  
//default value of nSplitter is 5 CCNrjaA  
this("","","",5); Q_$aiE  
} g=0`^APql  
~Y7>P$G)  
6U Q~Fv`]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )[C]1N=tK  
{ 1Mn=m w  
sSiteURL= sURL; zVKbM3(^  
sFilePath = sPath; l ~b# Y&  
sFileName = sName; p[2`H$A  
this.nSplitter = nSpiltter; S1p 4.qJ  
93Kd7x-3  
tg_xk+x  
} T`mG+"O  
E#[_"^n  
oCg|* c|+  
public String getSSiteURL() CBN,~wzP*  
{ ]$oo1ssZ1  
return sSiteURL; o,>9|EMQZ  
} w j !YYBH  
RZoSP(6  
J~Uq'1?  
public void setSSiteURL(String value) <tXk\ cOg  
{ -N $4\yp  
sSiteURL = value; OyH>N/  
} eS-akx^@  
MKPxF@N(  
[1nfSW  
public String getSFilePath() <|8N\FU{  
{ Q =9Ce@[  
return sFilePath; :%7y6V*  
} \e+h">`WgX  
"A\h+q-  
0`UI^Y~Q  
public void setSFilePath(String value) QiC}hj$  
{ B6ee\23  
sFilePath = value; 2T 3tKX  
} =hFIH\x  
o|(Ivt7jk  
!xcLJ5^W  
public String getSFileName() O/Cwm;&t  
{ =\~<##sRJ  
return sFileName; o-i9 :AHs  
} `& ufdn\j  
NH9"89]E  
o|`[X '  
public void setSFileName(String value) NW_i<#  
{ >vQ8~*xd  
sFileName = value; PtsQV!  
} OD[q u  
D[/h7Ha  
+a3H1 tt~  
public int getNSplitter() 8k +^jj  
{ !aQb Kp  
return nSplitter; wtM1gYl^  
} Xna58KF/  
_cvA1Q"  
":@\kw  
public void setNSplitter(int nCount) 59Lc-JJ  
{ Ui?iMtDr  
nSplitter = nCount; HOt,G _{  
} 4j|IG/m  
} sg`   
%\"<lyD  
Ls<^z@I  
/* {ooztC   
**Utility.java (vP<}  
*/ ?_ 476A  
package NetFox; ^?J3nf{  
f8e :J#jbS  
CiWz>HWH  
public class Utility { Oh# z zo  
wxJu=#!M  
S5o,\wT  
public Utility() uM)#T*(  
{ I'`90{I  
9Js+*,t  
HK NT. a  
} U7#C.Z  
_mWVZ1P  
//线程睡眠 Ie4\d2tQ;  
public static void sleep(int nSecond) <*Nd%Ca  
{ Gsn$r(m{K  
try{ NC%96gfD  
Thread.sleep(nSecond); j)ME%17  
} GJ5R <f9I  
catch(Exception e) ui RO,B}z  
{ s<>d& W 0=  
e.printStackTrace (); kx?f,^ -  
} BItH0r7  
} z~"Q_gme  
_?> x{![  
//日志 :6MV@{;PJ  
public static void log(String sMsg) iC{(vL0P+  
{  WD55(  
System.err.println(sMsg); YdDP;, DA  
} mW2D"-s  
n:|a;/{I]9  
577#A,O  
public static void log(int sMsg) .Hnhd/ c  
{ qv^P  
System.err.println(sMsg); gky+.EP.  
} )SZzA'  
} /!?b&N/d)  
EXMW,  
kXV;J$1  
/* /W GD7\G'8  
**TestMethod.java :.9Y  
*/ :w q][0)  
package NetFox; AJ+\Qs(0  
yg.o?eML  
:i4AkBNK  
public class TestMethod { fMIRr5  
5dGfO:Dy_  
NH;e|8  
public TestMethod() Qs '_\|/-  
{ ///xx/weblogic60b2_win.exe B(WmJ6e  
try{ }uNj#Uf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); denxcDFu/~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iX o(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _dELVs7OL  
fileFetch.start(); Zs(BViTb|  
} ^k*%`iQ  
catch(Exception e){e.printStackTrace ();} ~s-bA#0S  
^&D5J\][  
wz1nV}  
} ?wu@+  
-:95ypi  
I{ Ip  
public static void main(String[] args) \=D+7'3  
{ -RJ~Sky[  
new TestMethod(); t{g@z3  
} L(bDk'zi  
} {+zG.1o^  
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