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http断点续传简单实现(java)

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/* >,c'Z<TM  
**SiteFileFetch.java 82yfPQ&UI  
*/ 4\14HcTcK  
package NetFox; I\('b9"*  
import java.io.*; fs8C ^Ik>~  
import java.net.*; "VA'W/yv!  
R{{?wr6b$  
XZj3x',;  
public class SiteFileFetch extends Thread { .8]=yPm  
L.% zs  
-;GB Xq  
SiteInfoBean siteInfoBean = null; //文件信息Bean )T'~F  
long[] nStartPos; //开始位置 mJME1#j$/|  
long[] nEndPos; //结束位置 7}vx]p2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =T#?:J#a  
long nFileLength; //文件长度 5)p!}hWs  
boolean bFirst = true; //是否第一次取文件 0MN)Z(Sa  
boolean bStop = false; //停止标志 cp4~`X  
File tmpFile; //文件下载的临时信息 kjOI7`DU  
DataOutputStream output; //输出到文件的输出流 xm> y3WC  
WWv.kglz  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) kvam`8SeL  
public SiteFileFetch(SiteInfoBean bean) throws IOException - *xn`DH  
{ 14p{V} f3  
siteInfoBean = bean; Mqm9i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y$FhV~m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); gTg[!}_;\N  
if(tmpFile.exists ()) {1'M76T  
{ cEEnR1  
bFirst = false; F& ['w-n%  
read_nPos(); JUTlJyx8  
} KqWO9d?w.  
else {/!Yavx  
{ )9kp[hY  
nStartPos = new long[bean.getNSplitter()]; cxnEcX\   
nEndPos = new long[bean.getNSplitter()]; &8hW~G>(m  
} k j&hn  
L%/atl!  
7h\U}!  
QX+&[G!DZH  
} [B%:!Q)@  
{N@tJ,Fh{  
D1cnf"y^  
public void run() *.+N?%sAP)  
{ jgT *=/GH2  
//获得文件长度 #x(3>}  
//分割文件 ]9hhAT44  
//实例FileSplitterFetch /rv=ml pRL  
//启动FileSplitterFetch线程 >S:+&VN`M  
//等待子线程返回 TR!7@Mu 3  
try{ v8K4u)  
if(bFirst) $K_-I8e|  
{ 3q`Uq`t4mR  
nFileLength = getFileSize(); ;et(Yi;9  
if(nFileLength == -1) ?1Uq ud  
{ ;i&t|5y~  
System.err.println("File Length is not known!"); r\m2Oo)]  
} !GtCOr\'  
else if(nFileLength == -2) 6jz~q~ I  
{ &a";jO GB  
System.err.println("File is not access!"); `5Em: 8 M  
} ]!cLFXa  
else MG74,D.f  
{ T@Th?  
for(int i=0;i<nStartPos.length;i++) BU=Ta$#BZ  
{ u$+nl~p[&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NzbHg p  
} MDfC%2Q  
for(int i=0;i<nEndPos.length-1;i++) u{|^5%)  
{ QVWUm!  
nEndPos = nStartPos[i+1]; +aRHMH  
} X/23 /_~L`  
nEndPos[nEndPos.length-1] = nFileLength; &5 R-bYGW  
} y_{v&AGmgm  
} &(~"OD  
3 /LW6W|  
|JTDwmR  
//启动子线程 Tywrh9[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; g715+5z[  
for(int i=0;i<nStartPos.length;i++) "mAMfV0  
{ VPOp#;"%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VBe&of+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }1P v6L(o)  
nStartPos,nEndPos,i); jW]Fx:mQi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P.O/ZW>g  
fileSplitterFetch.start(); 0]l9x}  
} BDPF>lPf<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vPx#TXY=b}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;f2<vp;U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", CV *  
nEndPos = " + nFileLength); 2yndna-  
// fileSplitterFetch[nPos.length-1].start(); $ZnVs@:S  
G/V0Yn""  
/4,U@s)"/  
//等待子线程结束 n$ZxN"q <  
//int count = 0; Xh`Oin}<  
//是否结束while循环 RzqU`<//  
boolean breakWhile = false; 6('xIE(R  
l7uEUMV  
yeN(_t2.  
while(!bStop) #,rP1#?  
{ 8PvO_Gz5  
write_nPos(); u1/q8'RW  
Utility.sleep(500); 420cbD3a  
breakWhile = true; 4j~WrdI*  
A|BN >?.t  
WmZ,c_  
for(int i=0;i<nStartPos.length;i++) *5R91@xt  
{ c_syJ<  
if(!fileSplitterFetch.bDownOver) y?8V'.f|  
{ Fzn#>`qG  
breakWhile = false; _)^`+{N<  
break; seNH/pRb  
} qF4DX$$<  
} _H$Z }2g<z  
if(breakWhile) )Tad]Hd"W  
break; K?,`gCN}v  
Hv|(V3-  
{fu[&@XV  
//count++; ufS0UD8%H  
//if(count>4) hPrE  
// siteStop(); n16TQe"8  
} *ZF:LOnU  
s:Z1 ZAxv  
mp17d$R-  
System.err.println("文件下载结束!"); 3H,>[&d  
} )-S;j)(+  
catch(Exception e){e.printStackTrace ();} T%1Kh'92  
} 5 OF*PBZ  
q??N,  
Ox+}JB [  
//获得文件长度 ( ALsc@K  
public long getFileSize() `-<m#HF:)d  
{ 8:}$L)[V  
int nFileLength = -1; 3vF-SgCV  
try{ " {Nw K  
URL url = new URL(siteInfoBean.getSSiteURL()); S{ qn^\0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "gq _^&  
httpConnection.setRequestProperty("User-Agent","NetFox"); qN6GLx%  
Oa -~}hN  
R|dSjEs  
int responseCode=httpConnection.getResponseCode(); B-aJn8>/  
if(responseCode>=400) Axx{G~n![  
{ Xe\,:~  
processErrorCode(responseCode); kF7`R4Sz  
return -2; //-2 represent access is error ,4kipJ!,yK  
} QlWkK.<Z3_  
?+y# t?  
pt8#cU\  
String sHeader; 7' TXR[   
g<N3 L [  
$ iU~p  
for(int i=1;;i++) ;q" ,Bs  
{ > V%3w7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vX"jL  
//Utility.log(in.readLine()); gj1l9>f>]a  
sHeader=httpConnection.getHeaderFieldKey(i); 1A/li%  
if(sHeader!=null) D[CEg2$y  
{ He)dm5#fg  
if(sHeader.equals("Content-Length")) UQ)7uYQ5  
{ ;X[23A{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); R=s^bYdoy  
break; Rj {D#5  
} QD*(wj  
} -vBk,;^>  
else -Khb  
break; }J\KnaKo  
} 8:t1%O$  
} %'<m[wf^ o  
catch(IOException e){e.printStackTrace ();} kNTxYJ  
catch(Exception e){e.printStackTrace ();} R3} Z"  
aW#_"Y}v'  
m4kUA"n5  
Utility.log(nFileLength); ^tKJ}}  
K9f7,/  
%TRH,-@3h  
return nFileLength; n"Q fW~U  
} [:C!g#o  
Xu&4|$wB+  
MA5BTq<&  
//保存下载信息(文件指针位置) ?3Dsz  
private void write_nPos() vCtag]H2@  
{ }-ysP$  
try{ zj9aaZ}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); N^&T5cAC  
output.writeInt(nStartPos.length); NuKx{y}P  
for(int i=0;i<nStartPos.length;i++) oi}\;TG  
{ `(?x@Y>.Ht  
// output.writeLong(nPos); {"w4+m~+te  
output.writeLong(fileSplitterFetch.nStartPos); |&a[@(N:zf  
output.writeLong(fileSplitterFetch.nEndPos); ^)|1T#Tz  
} bLi>jE.%.  
output.close(); p3(&9~ s  
} }9ZcO\M  
catch(IOException e){e.printStackTrace ();} 5T;,wQ<  
catch(Exception e){e.printStackTrace ();} cE0Kvqe`  
} Ok2>%e  
YC0FXNV  
*FEY"W+bY  
//读取保存的下载信息(文件指针位置) 9Fm><,0'u  
private void read_nPos() 'HDbU#vD  
{ .]W A/}  
try{ Uw5`zl  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^YG.eT6iG  
int nCount = input.readInt(); Ws(#ThA  
nStartPos = new long[nCount]; 3Q"4-pd  
nEndPos = new long[nCount]; k,nRC~Irh  
for(int i=0;i<nStartPos.length;i++) K# dV.  
{ 0q ^dpM  
nStartPos = input.readLong(); +R?d6IjH  
nEndPos = input.readLong(); _K"X  
} Dx<CO1%z-  
input.close(); :X;AmLf`2u  
} /IN/SZx  
catch(IOException e){e.printStackTrace ();} sd~T  
catch(Exception e){e.printStackTrace ();} RW. >;|m  
} /K]<7  
oZ(T`5  
{|J'd+  
private void processErrorCode(int nErrorCode) E64d6z^7u  
{ /^z5;aG  
System.err.println("Error Code : " + nErrorCode); wFJ?u?b0Q  
} lfp'D+#p {  
<e&*Tx<8  
4aQb+t,  
//停止文件下载 "?Cx4<nsM  
public void siteStop() ?=h{`Ci^ $  
{ p4OiCAW;  
bStop = true; ndIU0kq3  
for(int i=0;i<nStartPos.length;i++) ;eRYgC  
fileSplitterFetch.splitterStop(); "*E%?MG  
icPg<>TQ  
SlZ>N$E  
} T=QV =21qn  
} =pP0d vn  
//负责部分文件的抓取 /)` kYD6  
**FileSplitterFetch.java q0hg0 DC[;  
*/ )} H46  
package NetFox; yS[Z%]bvU  
2nRL;[L*.  
E5<}7Pt  
import java.io.*; VfiMR%i}  
import java.net.*; NN9` jP2  
H `V3oS~}  
(fjAsbT  
public class FileSplitterFetch extends Thread { ] 7, mo  
6DG:imGl  
'B>%5'SdD  
String sURL; //File URL p ft6 @ 'q  
long nStartPos; //File Snippet Start Position 1wa zJj=v  
long nEndPos; //File Snippet End Position >"Z^8J  
int nThreadID; //Thread's ID bstc|8<  
boolean bDownOver = false; //Downing is over @{Q[M3l  
boolean bStop = false; //Stop identical u9*}@{,  
FileAccessI fileAccessI = null; //File Access interface +0Rr5^8u  
0/."R ;  
;_lEu" -  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x_oL~~@  
{ t4H@ZvAH0  
this.sURL = sURL; |QvG;{!  
this.nStartPos = nStart; {<HL}m@kQ  
this.nEndPos = nEnd; 6"Km E}  
nThreadID = id; _ s]=g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0NB6S&lI^k  
} GP5Y5 )  
MhNDf[W>  
=;/4j'1}9  
public void run() bV#U&)|  
{ "3*Chc  
while(nStartPos < nEndPos && !bStop) y4HOKJxI  
{ D %`64R  
D/w4u;E@  
? 5qo>W<7  
try{ 2@ >04]  
URL url = new URL(sURL); T7AFL=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /]Fs3uf  
httpConnection.setRequestProperty("User-Agent","NetFox"); *@q+A1P7@  
String sProperty = "bytes="+nStartPos+"-"; QM1-w^  
httpConnection.setRequestProperty("RANGE",sProperty); |yi3y `f  
Utility.log(sProperty); Ok+zUA[Wu  
9K@>{69WQ  
FBM 73D@`  
InputStream input = httpConnection.getInputStream(); T{={uzQeJJ  
//logResponseHead(httpConnection); u":D{+wC |  
^IxT.g  
B8^tIq  
byte[] b = new byte[1024]; ,*2%6t`N?  
int nRead; UlHRA[SCv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zv]-(<B  
{ iAX\F`  
nStartPos += fileAccessI.write(b,0,nRead); j w)Lofn  
//if(nThreadID == 1) ~a[]4\ m;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Y WSo:)LY  
} pCz;km  
"msCiqF{z  
Tw{H+B"uVz  
Utility.log("Thread " + nThreadID + " is over!"); ,#1ke  
bDownOver = true; WYQJ +z5  
//nPos = fileAccessI.write (b,0,nRead); FX"%  
} bh&,*Y6=  
catch(Exception e){e.printStackTrace ();} @^y/V@lDm  
} *hAeA+:  
} G qI^$5?  
2hV#3i  
{4 !%'~  
//打印回应的头信息 22\Buk}?  
public void logResponseHead(HttpURLConnection con) FDaHsiI:  
{ C+Wb_  
for(int i=1;;i++) "aN<3b  
{ GdavCwJ  
String header=con.getHeaderFieldKey(i); jK#y7E  
if(header!=null) . *>LD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~4[2{M.0>@  
Utility.log(header+" : "+con.getHeaderField(header)); v.)'b e*u  
else ~ X8U@f  
break; Y;je::"  
} R0;c'W)  
} a}a_&rf~Z  
YNbs* i&  
 O+1 e  
public void splitterStop() +vkqig  
{ a\\B88iRRZ  
bStop = true; d3T|N\(DL  
} (| Am  
}$V]00 X  
5j`"@C5;O  
} l/yLSGjM  
EA2BN}  
|H5){2V>K  
/* rd\mFz-SB  
**FileAccess.java []0`>rVq  
*//文件访问(定位,写) 6hYv  
package NetFox; 2](R}  
import java.io.*; !&TbE@Xk  
U KF/v  
.9> e r  
public class FileAccessI implements Serializable{ z.eqOPW  
+DM+@F  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B_M)<Ad  
RandomAccessFile oSavedFile; bslv_OxJ  
long nPos; jHBn^Nly  
3S:}fPR  
C^Tc9  
public FileAccessI() throws IOException \SnW(,`oX  
{ 3mZX@h@  
this("",0); O{&5/xBA  
} %,MCnu&Z  
4pkc9\  
F&;g< SD  
public FileAccessI(String sName,long nPos) throws IOException dW<.  
{ oo3ZYA  
oSavedFile = new RandomAccessFile(sName,"rw"); x2/|i? ZO  
this.nPos = nPos; 3j0/&ON  
oSavedFile.seek(nPos); P6S^wjk  
} <(?ahO5  
jt tlzCDn  
<8!mmOK1  
public synchronized int write(byte[] b,int nStart,int nLen) N2;T\xx,  
{ |A 7Yv  
int n = -1; :D-d`OyjG>  
try{ Ka2U@fK"  
oSavedFile.write(b,nStart,nLen); `8\pihww  
n = nLen; QY-P!JD  
} >Fz_]z   
catch(IOException e) b`E0tZcJ  
{ gPe*M =iF  
e.printStackTrace (); 0gHJ%m9s  
} w@.E}%bwq  
A2Rr*e  
b0x9}  
return n; Xgd!i}6Q  
} {8Hrb^8!  
wlC_rRj~  
qDhz|a#  
}  }Q`Kg8L  
;f[Ki$7  
6*kY7  
/* Mc~(S$FU$  
**SiteInfoBean.java  nq8mzI  
*/ XV)ej>A-V  
package NetFox; t3 *2Z u  
}{:H0)H*  
f&H):.  
public class SiteInfoBean { >AV-i$4eQ@  
xv's52x  
s}`ydwSg8  
private String sSiteURL; //Site's URL w@nN3U+  
private String sFilePath; //Saved File's Path ;_of'  
private String sFileName; //Saved File's Name waQNX7Xdn  
private int nSplitter; //Count of Splited Downloading File c _O| ?1  
QgEG%YqB  
bL!NT}y`  
public SiteInfoBean() f'aUo|^?  
{//nSplitter的缺省值为5 "2 ma]Ps  
//default value of nSplitter is 5 R"!.|fH6  
this("","","",5); +=|Q'V  
} n O$(\ z)  
U[c,cdA  
x<P$$G/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j3P)cz-0/L  
{ er,R}v  
sSiteURL= sURL; "Hg.pDNZ  
sFilePath = sPath; :bW}*0b-  
sFileName = sName; ]Tf.KUm  
this.nSplitter = nSpiltter; mDvZ 1aj  
KZ`d3ad  
{_ww1'|A  
} Bg"b,&/^u  
\UGs_5OT  
aIRCz=N  
public String getSSiteURL() * ?rw'  
{ Xl2Fgg}#  
return sSiteURL; y{s?]hLk  
} 1*[h$Z&H?  
TPq5"mco  
b3H~a2"d  
public void setSSiteURL(String value) t=~al8  
{ J Q%e'  
sSiteURL = value; I^[R]Js  
} /o.wCy,J<  
E[Tz%x=P  
HpSgGhL'J&  
public String getSFilePath() ]b.@i&M  
{ #|GP]`YT  
return sFilePath; z~A||@4'  
} <!Nj2>  
rV"<1y:g  
,@/b7BVv  
public void setSFilePath(String value) `U#*O+S-^  
{ PGP9-M  
sFilePath = value; 2!-ZNd:(+  
} LP7t*}PK  
C=h$8Q  
Dsm_T1X  
public String getSFileName() )j4]Y dJ  
{ %8yfF rk  
return sFileName; ?Re@`f+*  
} vZTX3c:,1  
s)_7*DY  
6QLWF @  
public void setSFileName(String value) ?<#6=  
{ rfkk3oy  
sFileName = value; dum! AO  
} YCj"^RC^  
?2 u_E "  
Gz+Bk5#{  
public int getNSplitter() Cl6y:21]K  
{ 1 [[` ^v  
return nSplitter; u<]-%ha$  
} TCX*$ac"  
8,a&i:C  
ot;j6eAH~E  
public void setNSplitter(int nCount) XGFU *g`kq  
{ d~D<;7M XJ  
nSplitter = nCount; z/.x*A=  
} =mn)].Wg  
} @8HTC|_vX  
5MQD:K2  
!\}Dxt  
/* ]~U4;  
**Utility.java ]chcRc[!  
*/ fS>W-  
package NetFox; W7WHH \L/O  
oR[,?qu@f  
;? '`XB!  
public class Utility { %q;3b fq@N  
R."<he ;  
{[jcT>.3j  
public Utility() 5H6m{ng  
{ 0F1 a  
drBWo|/  
`a ["`N^  
} hWJ\dwF  
z. VuY3  
//线程睡眠 YKJk)%;+w  
public static void sleep(int nSecond) <dV|N$WV  
{ z;zy k  
try{ sw[1T_S>  
Thread.sleep(nSecond); L oe!@c  
} o*_[3{FU  
catch(Exception e) ^ W eE%"  
{ al F*L  
e.printStackTrace (); GLB7h 9>  
} 9jDV]!N4  
} +6B(LPxgP  
\tye:!a?;@  
//日志 I?G m  
public static void log(String sMsg) H~i+: X=I  
{ 8v8?D8\=|  
System.err.println(sMsg); 5,:>.LRA  
} 4rO07)~l  
>DBaKLu\  
]ctUl #j  
public static void log(int sMsg) ]!d #2(  
{ MOP/q4j[  
System.err.println(sMsg); 'VS!<  
} lE78 Yl]  
} x>A(016:C  
/1zi(z   
\L}Soe'  
/* B# |w}hj  
**TestMethod.java $ii/Q:w T"  
*/ gGxgU$`#c  
package NetFox; "diF$Lj  
`J|bGf#  
|#D3~au   
public class TestMethod { Dkay k  
EA7 8&  
7"yA~e,l  
public TestMethod() skh6L!6*<  
{ ///xx/weblogic60b2_win.exe b/:9^&z  
try{ v?,_SVgAi  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); G%Hr c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "a6[FqTs  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \sEq r)\k  
fileFetch.start(); SQDllG84E  
} jutEb@nog  
catch(Exception e){e.printStackTrace ();} c/DB"_}!a  
0.'$U}#b  
z2vrV?:  
} OIGu`%~js  
-GLI$_lLF  
n2zJ'  
public static void main(String[] args) 26B]b{Iz{  
{ =H%c/Jty  
new TestMethod(); g,h'K  
} Wz)s#  
} _Jx.?8  
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