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http断点续传简单实现(java)

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/* m!<\WN6g  
**SiteFileFetch.java HttiX/2~  
*/ *Z|y'<s  
package NetFox; NH+(?TN  
import java.io.*; 27;ci:5  
import java.net.*; J~#;<e{\"  
D1__n6g[  
w8n|B?Sr  
public class SiteFileFetch extends Thread { )B[0JrcE  
HD(.BW7  
"HPB!)C8(  
SiteInfoBean siteInfoBean = null; //文件信息Bean i&VsW7  
long[] nStartPos; //开始位置 _cXqAo  
long[] nEndPos; //结束位置 } \ZaE~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 qi_Jywd:w  
long nFileLength; //文件长度 D9z|VIw8  
boolean bFirst = true; //是否第一次取文件 r#XT3qp$d  
boolean bStop = false; //停止标志 ?M[ A7?  
File tmpFile; //文件下载的临时信息 ;VWAf;U;B  
DataOutputStream output; //输出到文件的输出流 $sEy%-  
'Fmvu   
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) o<N  nV  
public SiteFileFetch(SiteInfoBean bean) throws IOException eopD5  
{ TYy.jFT-  
siteInfoBean = bean; V{JAB]?^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6L)%T02C  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); V,$0p1?J  
if(tmpFile.exists ()) ]Ux<aiY]a  
{ 5H ue7'LS  
bFirst = false; b#X^=n2  
read_nPos(); >Q(3*d >  
} 3+XOZh8  
else 3`k;a1Z#O'  
{ {~F4WjHJp  
nStartPos = new long[bean.getNSplitter()]; B[KJR?>  
nEndPos = new long[bean.getNSplitter()]; aoXb22]{  
} mya_4I m  
;Rv!k&Df  
5O\*h;U 6  
3g >B"t  
} a[ex[TRKe  
,G2TVjz  
2sJ(awN>  
public void run() 92 [; Y  
{ 3\B>lKhQ  
//获得文件长度 2RX!V@z.G  
//分割文件 Z4lO?S5%J  
//实例FileSplitterFetch YGrg  
//启动FileSplitterFetch线程 zRyuq1Zyc,  
//等待子线程返回 vMS |$L  
try{ 0PWg;>^'  
if(bFirst) ^Y'HaneoM  
{ >"C,@cN}B  
nFileLength = getFileSize(); 62Z#Y Q}x  
if(nFileLength == -1) R00eisd  
{ )BwjZMJ.N  
System.err.println("File Length is not known!"); +t?3T-@Ks  
} Xwhui4'w  
else if(nFileLength == -2) ( vca&wI!  
{ 9T1ZL5  
System.err.println("File is not access!"); u,UmrR  
} |]c8jG\h  
else DK$s&zf  
{ $f zaPD4.  
for(int i=0;i<nStartPos.length;i++) f\jLqZY  
{ G%s 2P.cd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Iu <?&9t  
} F F|FU<  
for(int i=0;i<nEndPos.length-1;i++) Pqn@ST  
{ }nL7T'$>  
nEndPos = nStartPos[i+1]; &sU?Ok6  
} w'UVKpG+  
nEndPos[nEndPos.length-1] = nFileLength; {QwHc5Bf  
} ](s'L8 (x  
} +1D+]*t_?[  
iB498t  
43@{JK9G  
//启动子线程 ?W)A   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h]TQn)X]  
for(int i=0;i<nStartPos.length;i++) [DF,^4g  
{ 7D;cw\ |  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hUF5fZqii  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~FN9 [aJF+  
nStartPos,nEndPos,i); xjVS   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yI"6Da6|y  
fileSplitterFetch.start(); 1#ft#-g}  
} @9lUSk^9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P9vA7[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /%;mqrdk  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hX=A)73(  
nEndPos = " + nFileLength); d&+h}O  
// fileSplitterFetch[nPos.length-1].start(); cj1cZ-  
ekWePL;rR2  
LL3#5AA"k|  
//等待子线程结束 "*Tb" 'O  
//int count = 0; v uoQz\  
//是否结束while循环 hBBUw0"  
boolean breakWhile = false; 6,0_)O}\b  
5Er2}KZJv,  
*^:N.&]  
while(!bStop) \Z+z?K O  
{ #3+!ee27#  
write_nPos(); TL}++e 7+  
Utility.sleep(500); (G[ *|6m  
breakWhile = true; )3>hhuaa  
{qN 5MsY  
%'X[^W  
for(int i=0;i<nStartPos.length;i++) D"a~ #^  
{ |v({-*7  
if(!fileSplitterFetch.bDownOver) /!3@]xz*  
{ PEW=@xj2y  
breakWhile = false; 'LE =6{#  
break; }n4V|f-  
} #~<0t(3Q  
} #g]vc_V  
if(breakWhile) `0Oh_8"  
break; "$2 y-|  
n:{qC{D-qS  
'coV^~qy  
//count++; pLLGus+W  
//if(count>4) Bi @2  
// siteStop(); %>g3~yl  
} `#;e)1  
m>MB7,C;N  
"-vW,7y  
System.err.println("文件下载结束!"); f PM8f  
} *U P@9D  
catch(Exception e){e.printStackTrace ();} EV*IoE$W]=  
} d%V*|0c)  
tF{D= ;G  
/assq+H  
//获得文件长度 {/ BT9|LI  
public long getFileSize() "gDb1h)8  
{ =*r]) Vg^  
int nFileLength = -1; CnG+Mc^  
try{ 3_MS.iM  
URL url = new URL(siteInfoBean.getSSiteURL()); i? K|TC`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =5(>q5Z*  
httpConnection.setRequestProperty("User-Agent","NetFox"); $w);5o  
{M^3m5.^  
RT.D"WvT  
int responseCode=httpConnection.getResponseCode(); -UOj>{-  
if(responseCode>=400) d~JKH&x<  
{ i;_tI#:A  
processErrorCode(responseCode); MM x9(`t*.  
return -2; //-2 represent access is error PqiB\~o@Z  
} T^Ze3L]  
9Ru8~R/\  
B4i!/@0s  
String sHeader; g.zEn/SM  
yL2o}ZbS  
F)'.g d  
for(int i=1;;i++) z$?~Y(EY  
{ Vv.|br`;}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R' !  
//Utility.log(in.readLine()); 5a hVeY  
sHeader=httpConnection.getHeaderFieldKey(i); -6n K<e`  
if(sHeader!=null) ,I%g|'2  
{ +i@y@<l:+  
if(sHeader.equals("Content-Length")) !3*(N8_|#  
{ mg$]QnbAnH  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `CgaS#  
break; P dhEQ}H  
} n8".XS  
} >VN5`Zlw\C  
else '>' wK.  
break; 5sx1Zq7  
} vM*($qpAy  
} q@nP}Pv&5  
catch(IOException e){e.printStackTrace ();} ~e+\k>^eN  
catch(Exception e){e.printStackTrace ();} >U]C/P[+  
(3{YM(  
to=y#$_  
Utility.log(nFileLength); a *ushB  
{O7X`'[  
%\H|B0  
return nFileLength; o!{w"K  
} C ihAU"  
7]||UuF<  
~1W x =  
//保存下载信息(文件指针位置) }}>q2y  
private void write_nPos() 32/MkuY^u  
{ ,z-}t& _t  
try{ K%F,='P}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $0lD>yu  
output.writeInt(nStartPos.length); MBhWMCN2  
for(int i=0;i<nStartPos.length;i++) BE_ay-  
{ .7.b :Dn0  
// output.writeLong(nPos); |!"`MIw,  
output.writeLong(fileSplitterFetch.nStartPos); 06N}k<10O  
output.writeLong(fileSplitterFetch.nEndPos); !,Va(E|=  
} X@LRsg  
output.close(); -/g B|J  
} CJJzCVj  
catch(IOException e){e.printStackTrace ();} :QB<?HaS'  
catch(Exception e){e.printStackTrace ();} 9&` 2V  
} b/{t|io{  
.tzG_  
:]^P1sH[  
//读取保存的下载信息(文件指针位置) NT+?  #0I  
private void read_nPos() H=Y{rq@  
{ Ux}(?Z  
try{ Bhp-jq'!B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _PlKhv}  
int nCount = input.readInt(); )Ccq4i  
nStartPos = new long[nCount]; pXtXjb  
nEndPos = new long[nCount]; j{9D{  
for(int i=0;i<nStartPos.length;i++) nAjO6g6E  
{ [`rba'  
nStartPos = input.readLong(); glF; e T  
nEndPos = input.readLong(); 8F&=a,ps[  
} qIIv6''5@  
input.close(); {yB&xj[z  
} aM:nOt" S1  
catch(IOException e){e.printStackTrace ();} $l|qk  z  
catch(Exception e){e.printStackTrace ();} HLZ;8/|48m  
} U~j ^I^  
0QOBL'{7)  
W^] 3XJP  
private void processErrorCode(int nErrorCode) 'zGo?a  
{ s#tZg  
System.err.println("Error Code : " + nErrorCode); p~,]*y:XT  
} ^k#P5oV  
_J? Dq  
T3pmVl  
//停止文件下载 Ou1JIxZ)|  
public void siteStop() }0X:F`Y-  
{ "0cID3A$  
bStop = true; ek}a}.3 {  
for(int i=0;i<nStartPos.length;i++) zOa_X~!@  
fileSplitterFetch.splitterStop(); V*iH}Y?^p  
nY`RR C  
2VJR$Pao  
} %^>ju;i^O  
} !Y\D?rKZ  
//负责部分文件的抓取 <RG|Dx[:=  
**FileSplitterFetch.java DFd%9*N  
*/ NF0%}II&xK  
package NetFox; o)2W`i&  
 )8UWhl=  
AbYqf%~7`l  
import java.io.*; .On|uC)!  
import java.net.*; /gu%:vq  
LM-J !44  
hijgF@  
public class FileSplitterFetch extends Thread { GrAujc5|  
p n.T~"%  
'_/Bp4i  
String sURL; //File URL fmiz,$O4?  
long nStartPos; //File Snippet Start Position x>*Drm 7  
long nEndPos; //File Snippet End Position v!ujj5-$I  
int nThreadID; //Thread's ID yzLpK;  
boolean bDownOver = false; //Downing is over JMz;BAHT  
boolean bStop = false; //Stop identical 7e#?e+5+A  
FileAccessI fileAccessI = null; //File Access interface yA.4G_|I  
T|dY 2  
]5$eAYq  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException H+ 0$tHi  
{ 6^"=dn6K  
this.sURL = sURL; 'toa@5  
this.nStartPos = nStart; nx^]>w  
this.nEndPos = nEnd; F>-B 3x  
nThreadID = id; )Ib<F 7v  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *i- _6s  
} r;Gi+Ca5  
7qg{v9|,  
]jaQ[g$F  
public void run() P3nb2.  
{ N.]qU d  
while(nStartPos < nEndPos && !bStop) 8qu2iPOcZ  
{ V %YiAr>  
I S#FiH  
zOqn<Y@  
try{ !>e5z|1   
URL url = new URL(sURL); }c`fW&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jlBanGs?  
httpConnection.setRequestProperty("User-Agent","NetFox"); i]|Yg$  
String sProperty = "bytes="+nStartPos+"-"; F;l$.9?.s  
httpConnection.setRequestProperty("RANGE",sProperty); ,XIz?R>;c  
Utility.log(sProperty); xg NJeQ  
K,bo VFs  
|&[L?  
InputStream input = httpConnection.getInputStream(); 5c^Z/ Jl$c  
//logResponseHead(httpConnection); u a~CEs  
5KDGSo  
""1^k2fj  
byte[] b = new byte[1024]; CFqJ/ ''  
int nRead; p Wt) A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ;+<&8.=,)  
{ 1!1 beR]  
nStartPos += fileAccessI.write(b,0,nRead); &b?LP]   
//if(nThreadID == 1) `(f!*Ru@/z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sM?MLB\Za  
} %T)oCjM[\  
kWe{r5C7  
}2uI?i8  
Utility.log("Thread " + nThreadID + " is over!"); hvuIxqv!y  
bDownOver = true; %9M~f*  
//nPos = fileAccessI.write (b,0,nRead); 0LfU=X0#7  
} &znQ;NH#  
catch(Exception e){e.printStackTrace ();} KA){''>8  
} & M~`:R  
} LF~*^n>  
Ircp``g  
9f',7i  
//打印回应的头信息 ZP;j9 T!  
public void logResponseHead(HttpURLConnection con) P  '>SmQ  
{ $T`<Qq-r  
for(int i=1;;i++) )Lwc  
{ 4 &_NJ\  
String header=con.getHeaderFieldKey(i); {e[c  
if(header!=null) :bWUuXVtJ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); NLrPSqz  
Utility.log(header+" : "+con.getHeaderField(header)); OnF3lCmu  
else IZ =Mlu  
break; HE'2"t[a  
} {iv<w8CU)  
} dd\n8f  
EvWzq%z l  
5o6>T!  
public void splitterStop() cu%C"  
{ H]$)Eg%6  
bStop = true; lNL6M%e$Q  
} 't_[dSO  
0MkSf*  
=Uj-^qcE  
} "v`   
Z7_ zMM  
)E,\H@A  
/* y-j\zK  
**FileAccess.java 1xbK'i:-S  
*//文件访问(定位,写) B7]C]=${m  
package NetFox; }yJ$SR]t  
import java.io.*; *_KFW@bC:  
,Vh{gm1  
Y;e,Gq`  
public class FileAccessI implements Serializable{ "7v@Rye  
2con[!U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 m <w "T7  
RandomAccessFile oSavedFile; Ojt`^r!V  
long nPos;  wAz&"rS  
+q)5dYRzV  
Uv?|G%cD-  
public FileAccessI() throws IOException El o Me~a3  
{ OzQ -7|m'J  
this("",0); ]Lm9^q14m  
} 7yx$N n`(  
>A<bBK#  
vk?skN@  
public FileAccessI(String sName,long nPos) throws IOException 5i-Rglo  
{ OI?K/rn  
oSavedFile = new RandomAccessFile(sName,"rw"); ph_4q@  
this.nPos = nPos; 7yz4'L  
oSavedFile.seek(nPos); Vm df8[5  
} n':!,a[  
.p=sBLp8  
*0}3t <5  
public synchronized int write(byte[] b,int nStart,int nLen) Qhw^S*  
{ %<\6TZr  
int n = -1; !Yw3 d   
try{ TD9;kN1`  
oSavedFile.write(b,nStart,nLen); 8-lOB  
n = nLen; 5 gv/Pq&  
} ! /NG.Wf  
catch(IOException e) J%jB?2 1:o  
{ c= x,ijY "  
e.printStackTrace (); qt3PXqR7 :  
} cI=r+ OGk*  
mCWhUBghR  
BA:yQ  
return n; 2PeR   
} W0C@9&pn6  
<N`J`J-[  
#_|sgS?1  
} K3' niGT  
p?2Y }9  
d~?X/sJ t  
/* (s1k$@d  
**SiteInfoBean.java |8.(XsN  
*/ t2V0lyeL  
package NetFox; `$~Rxz Z g  
Fk6x<^Q<w  
8UMF q  
public class SiteInfoBean { $rhgzpZ!X_  
e{A9r@p!  
+MB!B9M@  
private String sSiteURL; //Site's URL b-Z4 Jo G  
private String sFilePath; //Saved File's Path wBInq~K_  
private String sFileName; //Saved File's Name xxm%u9@s  
private int nSplitter; //Count of Splited Downloading File /c$\X<b);  
r&2~~_d3y  
D!oc>K$B  
public SiteInfoBean() %&Fk4Z}M  
{//nSplitter的缺省值为5 +*n-<x5"  
//default value of nSplitter is 5 e.*%K!(  
this("","","",5); cDoo*  
} $%%os6y2v  
+e-,ST&w(  
e|rg;`AW  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) WH$e2[+Y  
{ F*Z=<]<+  
sSiteURL= sURL; x%<  
sFilePath = sPath; =B];?%  
sFileName = sName; 1Fe^Qb5G  
this.nSplitter = nSpiltter; `?y<>m*  
-3&G"hfK  
M^7MU}5w  
} rFZrYm  
`$YP<CJeq  
jr /lk  
public String getSSiteURL() $v`afd y  
{ O Lc}_  
return sSiteURL; )g|xpb  
} a6h>=uT [  
e2+BWKaU  
=X!IH d0  
public void setSSiteURL(String value) <|*'O5B  
{ #"ftI7=42  
sSiteURL = value; MzYavg`  
} Z/6qG0feJ  
$f pq 3  
]{ d[  
public String getSFilePath() {u\%hpD_  
{ ~RBrSu)  
return sFilePath; IhiGP {  
} BYM3jXWi0v  
R|P_GN6 >  
4<X!<]3]  
public void setSFilePath(String value) |3{&@7  
{ npDIX  
sFilePath = value; zD)pF1,7:8  
} DOQc"+  
!>(RK"KWq]  
OI0B:()  
public String getSFileName() @+Y8*Rj\3  
{ `T2<<<  
return sFileName; J R PSvP\  
} +y#T?!jQYj  
O%f8I'u$  
;XC@ =RpX  
public void setSFileName(String value) U{ ;l0 2S  
{ e.o;eD}"  
sFileName = value; *RR[H6B^]X  
} f&hwi:t  
C*I(|.i@  
#Y93y\  
public int getNSplitter() dp5f7>]:(  
{ sLcFt1  
return nSplitter; R 4wr  
} +jqj6O@Tjr  
 jAND7&W  
t=R6mjb  
public void setNSplitter(int nCount) 6S.~s6o,  
{ Hwm?#6\5  
nSplitter = nCount; jko"MfJ  
} 2uk x (Z  
} 7@PIM5h  
[<wbbvXR  
=/+#PVO  
/* X['2b78k  
**Utility.java nN3$\gHp8i  
*/ [ut#:1h^  
package NetFox; Ra3ukYG[  
!7U\J]  
JeY' 8B  
public class Utility { ^*^/]vM  
uO >x:*^8  
bO<0qM~  
public Utility() S^cH}-+  
{ }wSy  
Hh kN^S,  
D6Y6^eS-  
} {BO|u{C  
137Xl>nO  
//线程睡眠 (\dK4JJ  
public static void sleep(int nSecond) 2D([Z-<i  
{ BN@,/m9OQ%  
try{ mEQ!-p   
Thread.sleep(nSecond); {$^SP7qV#>  
} !Zbesp KZ  
catch(Exception e) _a+ICqR  
{ ex?\ c"  
e.printStackTrace (); RP(/x+V  
} ewB!IJxh  
} 8,o17}NY,  
3AlqBXE"Z<  
//日志 L8V3BH7B  
public static void log(String sMsg) ?Ay3u^X  
{ (Q-I8Y8l8  
System.err.println(sMsg); qi+&|80T.  
} [.q(h/b  
vZajT!h  
'H FKBp  
public static void log(int sMsg) j[P8  
{ aQcN&UA@  
System.err.println(sMsg); (3md:r<-  
} P 4;{jG  
} &.*uc|{  
B50 [O!  
(BERY  
/* k_3j '  
**TestMethod.java Qa$NBNxKl  
*/  v_sm  
package NetFox; 7aQcP  
7nz!0I^   
hXX1<~k  
public class TestMethod { 8mgQu]>  
n=`w9qajd  
viuiqs5[Bi  
public TestMethod() "E>t, D  
{ ///xx/weblogic60b2_win.exe p,n\__  
try{ |5 xzl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =w <VT%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); y3yvZD  
SiteFileFetch fileFetch = new SiteFileFetch(bean); G[q9A$yw  
fileFetch.start(); 0RyFv+  
} yx0Q+Sm1:  
catch(Exception e){e.printStackTrace ();} O3!d(dY=_  
:pd&dg!5  
Bp0bY9xLg_  
} <lOaor c  
F14(;'Az  
)!C7bTv 4  
public static void main(String[] args) <*Y O~S(R  
{ w4{y "A  
new TestMethod(); 8U^D(jrz  
} IT1P Pm  
} nC~fvyd<P  
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