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http断点续传简单实现(java)

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/* MA+{7 [  
**SiteFileFetch.java fq(3uE]nC  
*/ $h|8z  
package NetFox; c :u2a/Q?  
import java.io.*; - (VX+XHW  
import java.net.*; l<UJ@XID$  
9xRor<  
83pXj=k<  
public class SiteFileFetch extends Thread { a=r^?q'/  
AiUK#I  
0 czEA  
SiteInfoBean siteInfoBean = null; //文件信息Bean *n*po.Xr  
long[] nStartPos; //开始位置 .B_a3K4'{^  
long[] nEndPos; //结束位置 ."h>I @MH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ey]P >J  
long nFileLength; //文件长度 +"3K)9H  
boolean bFirst = true; //是否第一次取文件 dk.VH!uVb  
boolean bStop = false; //停止标志 [ J6q(} f  
File tmpFile; //文件下载的临时信息 (;2]`D [x  
DataOutputStream output; //输出到文件的输出流 QN8.FiiD  
ZJ'FZ8Sx  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) nA.~}  
public SiteFileFetch(SiteInfoBean bean) throws IOException *GC9o/  
{ 5@`DS-7h  
siteInfoBean = bean; p77  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9D H}6fO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); b\^9::oY  
if(tmpFile.exists ()) q:3HU<  
{ X@^"@  
bFirst = false; I7HP~v~  
read_nPos(); 0 ChdFf7  
} h%!N!\  
else !--A"  
{ 4qg] oiT  
nStartPos = new long[bean.getNSplitter()]; q|xic>.  
nEndPos = new long[bean.getNSplitter()]; RrRE$g  
} PJ'.s  
{PQ!o^7y  
.Eg[[K_iD  
)/4U]c{-  
} I>%@[h,+  
>o8N@`@VK-  
z|WDqB%/I  
public void run() p'YNj3&u  
{ ;eiqzdP  
//获得文件长度 JTfG^Nv>K  
//分割文件 BZs?tbf  
//实例FileSplitterFetch Z*M-PaU}  
//启动FileSplitterFetch线程 { , zg  
//等待子线程返回 "&N1$$  
try{ 93fClF|@  
if(bFirst) 1xt N3{c  
{  mIkc +X  
nFileLength = getFileSize(); JN<IMH  
if(nFileLength == -1) hwB>@r2  
{ 2` j#eB1  
System.err.println("File Length is not known!"); riY[p,  
} q3$;lLsb;j  
else if(nFileLength == -2) iVqa0Gl+}  
{ Yn1CU  
System.err.println("File is not access!"); 5$Aiez~tBq  
} dRPX`%J  
else .qG*$W2f  
{ @T 8$/  
for(int i=0;i<nStartPos.length;i++) Gw0MDV&[  
{ 1)N{!w`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Q2HULz{  
} oCR-KR>{Q  
for(int i=0;i<nEndPos.length-1;i++) g xf|L>=  
{ T!pjv8y@R  
nEndPos = nStartPos[i+1]; [sweN]b6F  
} xXm:S{I  
nEndPos[nEndPos.length-1] = nFileLength; SM@RELA'Lb  
} ^VAvQ(b!:i  
} +\@WOs  
sPUn"7  
K^fH:pV  
//启动子线程 L fx$M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %?~`'vYoi  
for(int i=0;i<nStartPos.length;i++) D?< R5zp  
{ cp\A xWtUZ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), + ZxG<1&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0'O*Y ]h+  
nStartPos,nEndPos,i); )i{B:w\ ^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X`E3lgfqT  
fileSplitterFetch.start(); gjnTG:}}}+  
} .ECT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L4C_qb k;:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); H^\2,x Z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =f*Wj\  
nEndPos = " + nFileLength); _]~= Kjp  
// fileSplitterFetch[nPos.length-1].start(); 0zvA>4cq)  
,@*Srrw  
Wu9))Ir  
//等待子线程结束 #Z.2g].  
//int count = 0; DHnu F@M  
//是否结束while循环 [J71aH  
boolean breakWhile = false; K=`;D  
n'-?CMH`  
d:V6.7>,  
while(!bStop) 2UGnRZ8:1Y  
{ v1Wz#oP  
write_nPos(); ]E/~PV  
Utility.sleep(500); /K2=GLl;  
breakWhile = true; WFBVAD  
`[*nUdG  
4v("qNw#  
for(int i=0;i<nStartPos.length;i++) I/ q>c2Pw$  
{ h72#AN  
if(!fileSplitterFetch.bDownOver) ?U;KwS]%  
{ m2o)/:  
breakWhile = false; ")cJA f  
break; ZSo#vQ  
} F3L'f2yBG  
} a7Fc"s*  
if(breakWhile) Z[{k-_HgAm  
break; DfJHH)Ry}  
`0qBuE_^h  
[`eqma  
//count++; kA1C&  
//if(count>4) #kt3l59Ty  
// siteStop(); q0l=S+0  
} jbU=D:|  
xc HG5bg |  
l1h;ng6  
System.err.println("文件下载结束!"); O0Vtvbj  
} Ym WVb  
catch(Exception e){e.printStackTrace ();} 2W_p)8t> b  
} JXBTd=r_oM  
g,0u_$U  
)O~V3a  
//获得文件长度 3bGJ?hpp  
public long getFileSize() m<DiYxK  
{ _ `RCY^t  
int nFileLength = -1; Snav)Hb'  
try{ L:(>ON  
URL url = new URL(siteInfoBean.getSSiteURL()); ?1G7=R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O" <W<l7Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); !)}3[h0  
I,:R~^qJ8v  
38[ko 3  
int responseCode=httpConnection.getResponseCode(); qXH\e|  
if(responseCode>=400) D]s8w  
{ $\DOy&e  
processErrorCode(responseCode); J9kmIMq-C  
return -2; //-2 represent access is error Wxi|(}  
} @"\j]ZEnY  
Dj~]]  
99\;jz7  
String sHeader; JE<zQf(&  
*7ggw[~  
b~1]}9TJ  
for(int i=1;;i++) PyS~2)=B  
{ B4<W%lm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); RO([R=.`/  
//Utility.log(in.readLine()); TH`zp]0  
sHeader=httpConnection.getHeaderFieldKey(i); ^+ hJ& 9W  
if(sHeader!=null) lO)0p2  
{ wO&edZ]zb^  
if(sHeader.equals("Content-Length")) X/ \5j   
{ d"1DE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); qm.30 2  
break; fVU9?^0/)9  
} 6evW O!  
} )]=1W  
else = }&@XRLJ  
break; jL|y4  
} b)SU8z!NV&  
} w/L^w50pt  
catch(IOException e){e.printStackTrace ();} rcC}4mNe  
catch(Exception e){e.printStackTrace ();} PJ=N.x f}  
%7X<:f|N8x  
=1JS6~CTLN  
Utility.log(nFileLength); 6 N%fJ   
[|=#~(yYQ  
n>)'!   
return nFileLength; & *^FBJEa.  
} kHO2&"6  
.%.kEJh`  
qfO=_z ES  
//保存下载信息(文件指针位置) +s*OZ6i [  
private void write_nPos() X>[x7t:  
{ ^V DJGBk  
try{ D# $Fj  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0Cox+QJt  
output.writeInt(nStartPos.length); NZJ:@J=-  
for(int i=0;i<nStartPos.length;i++) `A]CdgA  
{ ?e`4 s f_~  
// output.writeLong(nPos); @>wD`<U|  
output.writeLong(fileSplitterFetch.nStartPos); <Rs#y:  
output.writeLong(fileSplitterFetch.nEndPos); |Ef\B] Ns  
} BFU6?\r  
output.close(); hi{#HXa  
} 7,i}M  
catch(IOException e){e.printStackTrace ();} m])!'Pa( =  
catch(Exception e){e.printStackTrace ();} >-2eZ(n)"  
} WIytgM  
*K9I+t"g  
Zz"b&`K  
//读取保存的下载信息(文件指针位置) l7 +#gPA  
private void read_nPos() 4G:I VK9  
{ _RLx;Tn)L  
try{ }(g`l)OX  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `EV" /&`  
int nCount = input.readInt(); ]=s!cfu  
nStartPos = new long[nCount]; [DW}z  
nEndPos = new long[nCount]; dQoZh E  
for(int i=0;i<nStartPos.length;i++) 4H7 3a5f  
{ =h?Q.vad  
nStartPos = input.readLong(); !Gv*iWg  
nEndPos = input.readLong(); <b-BJ2],k  
} a,o>E4#c  
input.close(); ?;{fqeJz  
} 'Zq$ W]i  
catch(IOException e){e.printStackTrace ();} s m42  
catch(Exception e){e.printStackTrace ();} J{GtH[  
} @WppiZ$  
U6hT*126  
Wvhg:vup  
private void processErrorCode(int nErrorCode) A),nkw0X  
{ #n=b*.  
System.err.println("Error Code : " + nErrorCode); KY)r kfo B  
} Zk#^H*jgx  
VZOf|o  
-1tdyCez  
//停止文件下载 -rU~  
public void siteStop() V:M$-6jv  
{ "W_C%elg  
bStop = true; P);: t~  
for(int i=0;i<nStartPos.length;i++) ]!>ThBMa  
fileSplitterFetch.splitterStop(); "J0,SFu:  
9m2_zfO[ w  
S ("Zzq`  
} .s4hFB^n  
} SZOcFmC?  
//负责部分文件的抓取 QjW7XVxB#N  
**FileSplitterFetch.java -Yaw>$nJ  
*/ O<3i6   
package NetFox; 'qTMY*  
> ,L'A;c}  
,`7;S,f  
import java.io.*; =-M)2&~L~  
import java.net.*; j@c fR  
\NYtxGV[Z  
&9CKI/K:  
public class FileSplitterFetch extends Thread { 1a#oJU  
yVThbL_YJ  
[\o+I:,}wi  
String sURL; //File URL 1v TncU!  
long nStartPos; //File Snippet Start Position WZk\mSNV  
long nEndPos; //File Snippet End Position q% Eze  
int nThreadID; //Thread's ID |Rr^K5hmD  
boolean bDownOver = false; //Downing is over &a?&G'?  
boolean bStop = false; //Stop identical &"dT/5}6  
FileAccessI fileAccessI = null; //File Access interface _VU/j9<+  
ETP}mo  
"7R"(.~>  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <!.'"*2  
{ T^-fn  
this.sURL = sURL; t#+X*'/  
this.nStartPos = nStart; R5LzqT,/N:  
this.nEndPos = nEnd; 0\t k/<w2  
nThreadID = id; 9wP_dJvb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $!c)%qDq  
} %Z-^Bu8;y  
i2{xW`AcUh  
fP`g#t)4Tu  
public void run() /^~3Ib8Fw+  
{ V/Hjd`n)`i  
while(nStartPos < nEndPos && !bStop) T`g.K6$b  
{ /#Y)nyE  
_A*5BAB:h(  
~mc7O  
try{ $'3`$   
URL url = new URL(sURL); T>(nc"(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <dx xXzLT  
httpConnection.setRequestProperty("User-Agent","NetFox"); uX{n#i,~L  
String sProperty = "bytes="+nStartPos+"-"; V\zf yH\~  
httpConnection.setRequestProperty("RANGE",sProperty); &x{CC@g/  
Utility.log(sProperty); N9r}nqCN  
^5TSo&qZ  
YmM+x=G:  
InputStream input = httpConnection.getInputStream(); :>to?~Z1  
//logResponseHead(httpConnection); 3kFOs$3  
!|`G<WD  
P  F!S  
byte[] b = new byte[1024]; "}UJ~ j).  
int nRead; -SaH_Nuj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E 3b`GRay  
{ J=4R" _yo  
nStartPos += fileAccessI.write(b,0,nRead); V,bfD3S3  
//if(nThreadID == 1) oxE'u<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A87JPX#R?  
} SU OuayE  
U0'>(FP~2  
U'S}7gya  
Utility.log("Thread " + nThreadID + " is over!"); #%k!`?^fbK  
bDownOver = true; 3*$A;%q  
//nPos = fileAccessI.write (b,0,nRead); gK/mm\K@  
} t>|Y-i3cb  
catch(Exception e){e.printStackTrace ();} |R:gu\gG  
} ?Y2ZqI  
} W R@=[G#TJ  
Ed9ynJ~)X  
D.o|pTZ  
//打印回应的头信息 a&~_ba+  
public void logResponseHead(HttpURLConnection con) kH1hsDe|&y  
{ Z<ozANbk  
for(int i=1;;i++) Z^,C><Yt  
{ `m?%{ \  
String header=con.getHeaderFieldKey(i); /*g3TbUs  
if(header!=null) !7!xJ&/V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2<wuzP|  
Utility.log(header+" : "+con.getHeaderField(header)); T6JN@:8  
else ^RytBwzKM  
break; 8RWfv}:X  
} V0 x[sEW  
} r  H;@N  
j?%^N\9  
ZB GLwe  
public void splitterStop() 8 $0D-z  
{ Zpg/T K  
bStop = true; pDb5t>  
} "P HkbU  
~C=I{qzF+  
$A"kHS7T  
} ?>5[~rMn  
m\`dLrPX4j  
/ pzdX%7  
/* / PG+ s6  
**FileAccess.java K[0.4+  
*//文件访问(定位,写) D"0:n.  
package NetFox; ~4h<nc  
import java.io.*; e*p7(b-  
=LV7K8FSd  
#j -bT4!  
public class FileAccessI implements Serializable{ m7wD#?lm  
j_*$ Avy  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 jY%&G#4  
RandomAccessFile oSavedFile; Bz<T{f  
long nPos; 4Gs#_|!  
"V-k_d "  
3~Od2nk(x  
public FileAccessI() throws IOException \7PPFKS  
{ y\K r@;q0w  
this("",0); iSu7K&X9q  
} RUqN,C,m5I  
a5=8zO#%g  
"s!!\/^9C  
public FileAccessI(String sName,long nPos) throws IOException \MBbZB9@  
{ >QO^h<.>  
oSavedFile = new RandomAccessFile(sName,"rw"); _+PiaJ&'  
this.nPos = nPos; #\s*>Z  
oSavedFile.seek(nPos); |{ W4JFKJ  
} G2 A#&86J{  
O O?e8OU  
"%fh`4y3\  
public synchronized int write(byte[] b,int nStart,int nLen) ws8@y r<R  
{ +GCN63 nX  
int n = -1; -n&g**\w  
try{ -!MrG68  
oSavedFile.write(b,nStart,nLen); R<. <wQ4I  
n = nLen; Pyh+HD\  
} j1{|3#5V  
catch(IOException e) o V"d%ks  
{ ]<b$k  
e.printStackTrace (); 0K/Pth"*  
} MzjV>.  
s~e<Pr?yu  
GL;@heP  
return n; j>j Zg<}J  
} Ku;|Dz/=o  
DUH\/<^g  
x/~qyX8vo  
} ]xGo[:k|E  
F6>K FU8  
8vQGpIa,  
/* p7 s#j  
**SiteInfoBean.java eu=G[>  
*/ AI KLJvte  
package NetFox; q5 eyle6  
m$N` Xj  
Br/qOO:n$}  
public class SiteInfoBean { [/dGOl+  
F`!B!uY  
L8OW@)|  
private String sSiteURL; //Site's URL b#ga  
private String sFilePath; //Saved File's Path 5)712b(&  
private String sFileName; //Saved File's Name NUxOU>f  
private int nSplitter; //Count of Splited Downloading File -CV_yySc  
WFWQ;U{|  
d)@Hx8  
public SiteInfoBean() &6]+a4  
{//nSplitter的缺省值为5 ed3d 6/%HR  
//default value of nSplitter is 5 pypW  
this("","","",5); 'XW[uK]w)  
} { 'A`ram  
mL5Nu+#  
$;O-1# ]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) D$ X9xtT  
{ So?.V4aD_  
sSiteURL= sURL; )"( ojh  
sFilePath = sPath; eZ>KA+ C[  
sFileName = sName; Q1ox<-  
this.nSplitter = nSpiltter; S8=Am7D]1  
-dRnozs6W  
hKkUsY=R  
} C\-Abq c  
X?6E0/r&9  
M't~/&D#  
public String getSSiteURL() (I<]@7>  
{ c L+-- $L  
return sSiteURL; F4P=Wz]  
} |\HYq`!g%7  
| aAu 4   
_:R Q9x'  
public void setSSiteURL(String value) 3o).8b_3g  
{ wEQ7=Gyx  
sSiteURL = value; Kmk}Yz  
} $5(_U  
;N+ v x  
[{s 1= c  
public String getSFilePath() XsH(8-n0  
{ M lv  
return sFilePath; /KL;%:7  
} {z^6V\O5  
FWi c/7  
{"^LUw8fd  
public void setSFilePath(String value) WO}l&Q  
{ 6[b?ckvi  
sFilePath = value; '7'*+sgi$  
} ^Vbx9UN/  
O }ES/<an  
dwH8Zg$B  
public String getSFileName() R04%;p:k#  
{ )+Nm @+B  
return sFileName; fX:)mLnO/  
} ]q,5'[=~4h  
( M > C  
4$5d*7  
public void setSFileName(String value) ]"ZL<?3g  
{ SxX2+|0g`g  
sFileName = value; ^)JUl!5j]C  
} xJ-(]cO'  
`[OJ)tHE  
Sckt gp8  
public int getNSplitter() YmBo/IM  
{ %=ZN2)7{  
return nSplitter; Y)Os]<N1  
} Q3@MRR^tY  
QU#u5sX A  
Moldv x=M  
public void setNSplitter(int nCount) nV[0O8p2Md  
{ A^m]DSFOO  
nSplitter = nCount; [!g$|   
} i)@IV]]6yL  
} o@6hlLr  
a/ 4!zT   
B4&K2;fg_  
/* tny^sG/'  
**Utility.java t PJW|wo  
*/ ?k|}\l[X1  
package NetFox; 6\+ ZTw  
{vp|f~}zTw  
n#US4&uT4A  
public class Utility { p aQ"[w  
`<?{%ja  
a?d)l nk  
public Utility() #4yh-D"  
{ :2 Fy`PPab  
A^%li^qz  
7_=7 ;PQ<  
} 7U3b YU~;  
 Y ,  
//线程睡眠 Mnv2tnU]  
public static void sleep(int nSecond) ?<*mIf:?  
{ Au=9<WB%H  
try{ bG|aQ2HW  
Thread.sleep(nSecond); ( !THd  
} K3;lst>4  
catch(Exception e) +,g"8&>  
{ 7\T~K Yb?  
e.printStackTrace (); 8V08>M  
} ?*nFz0cs^  
} `R\nw)xq  
0afDqvrC6  
//日志 id" -eMwp  
public static void log(String sMsg) TwaK>t96[  
{ Jc3Z1Tt  
System.err.println(sMsg); b3vPGR  
} _Yms]QEZ  
2!Gb4V  
iC.k8r+~  
public static void log(int sMsg) /A4^l]H;+3  
{ eM) I%  
System.err.println(sMsg); 6^Q/D7U;s  
} ]zt77'J  
} MB"TwtW  
}5nVZ;  
h,!#YG@>  
/* ?x\tE]  
**TestMethod.java V~~4<?=A  
*/ 6F)^8s02h  
package NetFox; 4H]~]?F&  
:|5 \XV)>  
O,c}T7A'?w  
public class TestMethod { er%D`VHe  
cU[^[;4J<  
<aPbKDF~V  
public TestMethod() ~x #RIt  
{ ///xx/weblogic60b2_win.exe m) -D rbE  
try{ aQTISX;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [ e6zCN^t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,SQ`, C _5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); })#SjFq<V  
fileFetch.start(); kgZiyPcw  
} 2x<A7l)6  
catch(Exception e){e.printStackTrace ();} cN&]JS,  
VUF$,F9  
dU"ca|u  
} s-[v[w'E  
S!r,p};  
|}07tUq  
public static void main(String[] args) N,?4,+Hc-  
{ hUo}n>Aa  
new TestMethod(); )/{zTg8$?/  
} mV'XH  
} 9()d7Y#d/`  
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