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http断点续传简单实现(java)

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/* #m3!U(Og`  
**SiteFileFetch.java =an 0PN  
*/ c>wn e\(5H  
package NetFox; v R ! y#  
import java.io.*; 4C9k0]k2  
import java.net.*; %4Yq (e  
\Z-Fu=8J8^  
w+hpi5OH  
public class SiteFileFetch extends Thread { |^OK@KdL1  
\ F)}brPc  
P3TM5  
SiteInfoBean siteInfoBean = null; //文件信息Bean TmJXkR.5  
long[] nStartPos; //开始位置 ^(7Qz&q  
long[] nEndPos; //结束位置 -K6y#O@@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ym2"D?P (  
long nFileLength; //文件长度 E|_}?>{R  
boolean bFirst = true; //是否第一次取文件 Y9B"yV  
boolean bStop = false; //停止标志 dHtEyF  
File tmpFile; //文件下载的临时信息 Tj!rAMQk  
DataOutputStream output; //输出到文件的输出流 XjTu`?Na;  
'|G8yojz  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ?B<.d8i  
public SiteFileFetch(SiteInfoBean bean) throws IOException G}@a]EGm  
{ 4j<[3~:0 o  
siteInfoBean = bean; l6.&<0pLT  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); dyB@qh~H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); NdC5w-WY  
if(tmpFile.exists ()) c,}VC-  
{  =sk#`,,:  
bFirst = false; f0*_& rP  
read_nPos(); 6+:;M b_S  
} z<8VJZd  
else _!9I f  
{ `k(m2k ?  
nStartPos = new long[bean.getNSplitter()]; d"thM  
nEndPos = new long[bean.getNSplitter()]; $}=r 45e0K  
} xp*d:  
SUD~@]N1  
3!i{4/  
$ SZIJe"K  
} w^}* <q\  
#p-\Y7f  
rVp^s/A^;  
public void run() }$s QmR R  
{ t;_1/ mt  
//获得文件长度 k;r[m ,$  
//分割文件 W3n[qVZIC  
//实例FileSplitterFetch {,= hIXo>  
//启动FileSplitterFetch线程 Mo4c8wp&SM  
//等待子线程返回 !(y(6u#  
try{ )M8@|~~  
if(bFirst) }sp?@C,Z  
{ AnpO?+\HF  
nFileLength = getFileSize(); ,_K:DSiB  
if(nFileLength == -1) =>7czw:S 1  
{ X7?j90tH  
System.err.println("File Length is not known!"); Cj J n  
} Sp]ov:]%f  
else if(nFileLength == -2) Y@+9Ukd/  
{ [YJ*zO  
System.err.println("File is not access!"); u\km_e  
} U@:l~ xJ  
else <"av /`;  
{ @.pr}S/  
for(int i=0;i<nStartPos.length;i++) 4I2#L+W  
{ r>G||/Z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R S] N%`]  
} kD6Iz$tr  
for(int i=0;i<nEndPos.length-1;i++) 4v2JrC;  
{ qJw\<7m  
nEndPos = nStartPos[i+1]; 2FGCf} ,  
} ?i}wm`  
nEndPos[nEndPos.length-1] = nFileLength; *=77|Dba  
} m;S%RB^~H  
} JC}T*h>Ee  
6mjD@  
`0-i>>  
//启动子线程 5'_:>0}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; kqGydGh*"  
for(int i=0;i<nStartPos.length;i++) u3sr"w&  
{ |V^f}5gd  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K] &GSro  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `R*!GHro  
nStartPos,nEndPos,i); jEK{47i v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); id]}10  
fileSplitterFetch.start(); FV%|*JW[;N  
} <f0yh"?6VH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z 2lX^z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )2r_EO@3HP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m*v@L4t( 1  
nEndPos = " + nFileLength); VYrs4IFT$  
// fileSplitterFetch[nPos.length-1].start(); A$?o3--#]G  
TBgiA}|\D  
fqn;,!D?9  
//等待子线程结束 g^^^fKUp)  
//int count = 0; b)T6%2  
//是否结束while循环 ~}Z{hs)  
boolean breakWhile = false; B&}lYo  
<lWBhrz  
~u r}6T  
while(!bStop) x_= 3 !)  
{ A64c,Uv  
write_nPos(); h9 rrkV9  
Utility.sleep(500); ,u14R]  
breakWhile = true; uC2 5pH"  
+\J+?jOC4S  
 0 - u,AD  
for(int i=0;i<nStartPos.length;i++) pWKI^S  
{ #?~G\Ux0/  
if(!fileSplitterFetch.bDownOver) ,Uy~O(F t  
{ Po.izE!C  
breakWhile = false; zhU^~4F  
break; g5 y*-t  
} ^;@!\Rc  
} vQ[ Tc V  
if(breakWhile) e(9K.3 @{  
break; e{.P2rnh  
xP 3>8Y  
SnoEi~Da  
//count++; ,;yaYF 6|/  
//if(count>4) UiZ1$d*  
// siteStop(); ?y^ ix+ M  
} IOl0=+p  
f1t?<=3Ek<  
!KHbsOT?9  
System.err.println("文件下载结束!"); 3GZrVhU?m  
} M ED_#OS  
catch(Exception e){e.printStackTrace ();} a(x#6  
} T=fVD8  
Vtk}>I@%  
Y7`Dx'x  
//获得文件长度 _F jax  
public long getFileSize() (KR.dxzjf  
{ q&,uJo  
int nFileLength = -1; ; $UB@)7%  
try{ qx}*L'xB  
URL url = new URL(siteInfoBean.getSSiteURL()); oSP^ .BJ$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?q"9ZYX<  
httpConnection.setRequestProperty("User-Agent","NetFox"); KzB9 mMrO  
bbWW|PtWwP  
W}k)5<C4v  
int responseCode=httpConnection.getResponseCode(); 1["IT.,f.  
if(responseCode>=400) 'he&h4fm  
{ x!UGLL]_M  
processErrorCode(responseCode); ?)4c!3#  
return -2; //-2 represent access is error Q>\9/DjUp  
} 0|?DA12Z  
&I/C^/F&  
i.+#a2   
String sHeader; >  !WFY  
3 FLht L  
hy@e(k|S]U  
for(int i=1;;i++) > Cx;h=  
{ _Tf0L<A'R  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); q_:B=w+bC  
//Utility.log(in.readLine()); -J++b2R\%  
sHeader=httpConnection.getHeaderFieldKey(i); EyV6uk~  
if(sHeader!=null) 1(4IcIR5T;  
{ ;*e$k7}F  
if(sHeader.equals("Content-Length")) I0sw/,J/Z  
{ 8FBXdk?A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); wQX%*GbL2  
break; 0f,Ii_k bT  
} <:~'s]`zf  
} d'p@[1/  
else n Ayyjd3!S  
break; lUHpGr|U%  
} Il!#]  
} tEllkHyef  
catch(IOException e){e.printStackTrace ();} Q_A?p$%;L  
catch(Exception e){e.printStackTrace ();} It8@Cp.dU  
<Kq!)) J'  
-)E6{  
Utility.log(nFileLength); +Z/aG k;  
$9<P3J 1  
y?V#LW[^E  
return nFileLength; RZI4N4o  
} (M,*R v  
u]t#Vf-$u  
o&rNM5:  
//保存下载信息(文件指针位置) )n$RHt+:>  
private void write_nPos() T28Q(\C:}  
{ C?PgC~y)  
try{ +p &$`(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $-_@MT~  
output.writeInt(nStartPos.length); Ga $EM  
for(int i=0;i<nStartPos.length;i++) @ {8x L  
{ vce1'aW  
// output.writeLong(nPos); 3HB(rTw  
output.writeLong(fileSplitterFetch.nStartPos); Ndqhc  
output.writeLong(fileSplitterFetch.nEndPos); W$u/tRF  
} 3?yq*uE}  
output.close(); 6s&%~6J,  
} {i:Ayhq~&  
catch(IOException e){e.printStackTrace ();} EN~ha:9  
catch(Exception e){e.printStackTrace ();} EP]OJ$6I  
} l1}HJmom  
o%?~9rf]]  
M\bea  
//读取保存的下载信息(文件指针位置) 8f-B-e?k  
private void read_nPos() YN5p@b=FX  
{ __,}/|K2  
try{ @m ?&7{y#?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); -wn(J5NnR  
int nCount = input.readInt(); Xq.G vZS`  
nStartPos = new long[nCount]; A*+KlhT  
nEndPos = new long[nCount]; 8J+:5b_?  
for(int i=0;i<nStartPos.length;i++) 9rQw~B<S  
{ RyN?Sn5)  
nStartPos = input.readLong(); ;NrU|g/ksX  
nEndPos = input.readLong(); l|~SVk|  
} -hpMd/F  
input.close(); 1$rrfg  
} 7Dwf0Re`  
catch(IOException e){e.printStackTrace ();} oA $]%  
catch(Exception e){e.printStackTrace ();} I=wA)Bli1p  
} DX@*lM  
K7gqF~5x~  
vhu5w#]u*  
private void processErrorCode(int nErrorCode) :X ~{,J  
{ )x&OdFX  
System.err.println("Error Code : " + nErrorCode); &oqzQ+H  
} UNd+MHE74I  
/km'#f)/  
$eUJd Aetk  
//停止文件下载 **lT ' D  
public void siteStop() he1W22  
{ )w!*6<  
bStop = true; FVS@z5A8<=  
for(int i=0;i<nStartPos.length;i++) wMru9zyI  
fileSplitterFetch.splitterStop(); +G<9|-  
dnUiNs8  
d(j|8/tpA  
} 9mfP9  
} ixIfJ  
//负责部分文件的抓取 Xu#K<#V  
**FileSplitterFetch.java tD !$!\`O  
*/ 9x9~u8j  
package NetFox; Xw[|$#QKM  
+b6kU{  
6?(vXPpT$  
import java.io.*; Mny mV;y"  
import java.net.*; 8t Ef>  
?g #4&z.  
7Yd]#K{$  
public class FileSplitterFetch extends Thread { {pW(@4U  
q<*UeyE S  
\hT=U*dMR  
String sURL; //File URL # ~T K C|G  
long nStartPos; //File Snippet Start Position  Gu P1  
long nEndPos; //File Snippet End Position 60&4?<lR4  
int nThreadID; //Thread's ID ImVHX~ qHJ  
boolean bDownOver = false; //Downing is over d 1bx5U  
boolean bStop = false; //Stop identical dTW3mF4=  
FileAccessI fileAccessI = null; //File Access interface >@NGX-gp  
EkEU}2  
Rt10:9Kz$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nXnO]wXC  
{ vx8-~Oq{|;  
this.sURL = sURL; u4p){|x7s  
this.nStartPos = nStart; v22ZwP  
this.nEndPos = nEnd; iH""dtO  
nThreadID = id; BSib/)p   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0"to]=  
} fA>FU/r  
#'jd.'>  
KQ(7%W  
public void run() 1P+Te,I  
{ i VIpe  
while(nStartPos < nEndPos && !bStop) b#[7A  
{ IHlTp0?  
q-)Ynp4'  
c- {;P>L  
try{ N3}jLl/  
URL url = new URL(sURL); P_f^gB7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?h4Rh0rkX  
httpConnection.setRequestProperty("User-Agent","NetFox"); 49m}~J=*  
String sProperty = "bytes="+nStartPos+"-"; C0@[4a$8f  
httpConnection.setRequestProperty("RANGE",sProperty); h16i]V  
Utility.log(sProperty); $5n6C7  
jvfQG:F }  
4S+sz?W2j  
InputStream input = httpConnection.getInputStream(); #b?)fqRJL  
//logResponseHead(httpConnection); jsrIZbN  
RY]Vo8  
;_vo2zl1  
byte[] b = new byte[1024]; 9:tn! <^=I  
int nRead; #fR~ 7 KR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o1(?j}:c|  
{ (jY -MF3  
nStartPos += fileAccessI.write(b,0,nRead); HQO z  
//if(nThreadID == 1) /Sag_[i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9s}y*Vp  
} BCtm05  
8S_v} NUm  
};=44E'7  
Utility.log("Thread " + nThreadID + " is over!"); CnA0^JX  
bDownOver = true; )Cm7v@B   
//nPos = fileAccessI.write (b,0,nRead); 4Cdl^4(LT  
} 2'6:fr=R  
catch(Exception e){e.printStackTrace ();} ) HN,Az"  
} GE{u2<%@  
} 56 raZC  
TQ\\/e:  
~Uz1()ftz  
//打印回应的头信息 ,B=;NKo  
public void logResponseHead(HttpURLConnection con) sjISVJ?  
{ xEfz AJ5&  
for(int i=1;;i++) 0=^A{V!m  
{ M >BcYbXf  
String header=con.getHeaderFieldKey(i); }JKK"d}U  
if(header!=null) BCK0fk~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4pfv?!Oj  
Utility.log(header+" : "+con.getHeaderField(header)); 5@xl/  
else ;%H/^b.c  
break; @a{1vT9b  
} |tkhsQ-;  
} *j0kb"#  
g^dPAjPQ  
mSu1/?PS  
public void splitterStop() *&VqAc%qD  
{ iEJY[P1  
bStop = true; 3Y}X7-|)Z  
} aMaFxEW  
*75?%l  
(t\ F>A  
} n 7Bua  
2}^fhMS  
yA/b7x-c  
/* X-&U-S;  
**FileAccess.java "7*cF>FE8  
*//文件访问(定位,写) !h "6h  
package NetFox; # ~SQujgB  
import java.io.*; LK'|sO>|  
pg.z `k  
@+3@Z?!SZ  
public class FileAccessI implements Serializable{ ARD&L$AX  
^Cs5A0xo#s  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 oq<n5  
RandomAccessFile oSavedFile; &Jr~ )o   
long nPos; `2M`;$~ 5  
+Xg]@IS-eg  
M@n9i@UsO  
public FileAccessI() throws IOException AJ*FQo.U  
{ AIR\>.~"i*  
this("",0); Q'ok%9q!p  
} xgi/,Nk '  
fA]b'8  
'NJCU.lKm  
public FileAccessI(String sName,long nPos) throws IOException 5+gSpg]i  
{ YRy5.F%?  
oSavedFile = new RandomAccessFile(sName,"rw"); $RYsqX\v  
this.nPos = nPos; CqRG !J  
oSavedFile.seek(nPos); V*m@Rs!)2  
} G@O~*k1v  
<L1;aNN  
0pSqk/  
public synchronized int write(byte[] b,int nStart,int nLen) |G5Me  
{ %b H1We  
int n = -1; m&H@f:  
try{ #sOkD  
oSavedFile.write(b,nStart,nLen); ItZqLUJ m  
n = nLen; Fnnk }I}  
} 1%?J l~M  
catch(IOException e) pD+_ K  
{ a/Cd;T2  
e.printStackTrace (); .7ZV: m  
} k|^e=I   
3}@!TI  
5 ,0fL  
return n;  vj+x(  
} z4 snH%q  
n6PXPc  
b`@aiXN)+  
} wX_s./#JJ  
P+m{hn~%  
<23oyMR0  
/* &gn^i!%Z)  
**SiteInfoBean.java ~f[AEE~,s+  
*/ 1Qi5t?{  
package NetFox; ,<[Q/:}[  
!18M!8Xea  
[f'V pId8  
public class SiteInfoBean { :<    
|z!Y,zaX  
3J2j5N:g  
private String sSiteURL; //Site's URL j0p'_|)(  
private String sFilePath; //Saved File's Path 6iiH+Nc  
private String sFileName; //Saved File's Name zqaz1rt[  
private int nSplitter; //Count of Splited Downloading File =kp-[7  
O<0G\sU  
z9k3@\7  
public SiteInfoBean() rKR2v (c  
{//nSplitter的缺省值为5 !+;'kI2  
//default value of nSplitter is 5 X\r?g  
this("","","",5); nMK,g>wp  
} HMQi:s7%  
q1Ja*=r  
?h;Zdv>`xz  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~bp^Q| wM  
{ jpl"KN?X  
sSiteURL= sURL; CH6^;.  
sFilePath = sPath; fa7I6 i  
sFileName = sName; ZgN )sVJ  
this.nSplitter = nSpiltter; fZqMznF  
nQ*9|v4  
E,]G Ek  
} 9'tElpDJ6#  
;+%(@C51GE  
zCvt"!}RRa  
public String getSSiteURL() s3+^q  
{ .^<4]  
return sSiteURL; ]UR@V;JG  
} }n+#o!uEf  
6]=$c<.&  
de?Bn+mvi.  
public void setSSiteURL(String value) S H"e x,=  
{ cxBu2( Y  
sSiteURL = value; Hshm;\'  
} tpJe1J<  
YQyf:xJ  
~ kdxJP"  
public String getSFilePath() 5]/i[T_  
{ bk@F/KqL  
return sFilePath; ~bSPtH ]6d  
} GA, 6G [E  
wf4?{H  
"XWrd [Df  
public void setSFilePath(String value) CNCWxu  
{ Cv@ZzILyoK  
sFilePath = value; .w/_Om4T*b  
} K:!|xr(1d  
`'Fz :i  
*_ 2db   
public String getSFileName() D<=:9  
{ nE!h&}(  
return sFileName; (nWi9(}J  
} A.a UWh  
E2M|b  
@Sxb}XI!f  
public void setSFileName(String value) i%m]<yElm  
{ kW"6Gc&HUN  
sFileName = value; :Ogt{t  
} #&JhA2]q  
j[z o~Y4z  
#HjiE  
public int getNSplitter() Ww9%6 #i t  
{ &,pL3Qos  
return nSplitter; KLpe!8tAe  
} Xx~za{p  
FOB9J.w4  
D$W&6'  
public void setNSplitter(int nCount) 26yjQ  
{ H 1`}3}"  
nSplitter = nCount; otQulL)T/  
} ;A ~efC^<  
} Tw|cgB  
3<ikMUq&  
7B@[`>5?%L  
/* N/ 7Q(^  
**Utility.java E1(2wJ-3"  
*/ KkVFY+/)  
package NetFox; N"X;aVFs_  
?[ n{M  
p>w{.hC@  
public class Utility { M_-LI4>  
BU-m\Kf)  
^oNk}:>  
public Utility() 0/7y&-/(  
{ zJE$sB.f  
Bvke@|]kW  
F!FXZht$P  
} ykY#Y}?^  
0'Kbh$LU  
//线程睡眠 r;gtfX*  
public static void sleep(int nSecond) pBW|d\8  
{ .VFa,&5;3  
try{ 9>y6zFTV  
Thread.sleep(nSecond); 7X \azL  
} ! &f(X s  
catch(Exception e) vYT%e:8)q  
{ Nqih LUv  
e.printStackTrace (); E'|@hL-jn  
} CAGaZ rx  
} .G"UM>.}d  
GtQ$`~r  
//日志 pkd#SY  
public static void log(String sMsg) JI{|8)S  
{ mez )G|  
System.err.println(sMsg); [ugBVnma  
} fmuAX w>  
QLx]%E\  
s bf\;_!  
public static void log(int sMsg) *h=|KOS  
{ >Qk4AMIO  
System.err.println(sMsg); uWs5 +  
} >EQd;Af  
} @ lo6?9oNo  
4a'GWzUtS  
;t'~  
/* 3B }Oy$p  
**TestMethod.java ,uEi*s>  
*/ +9S_H(  
package NetFox; !}u'%  
crV2T  
{1H3VSYq  
public class TestMethod { |Qq_;x]  
,j{$SuZ M  
J|k~e,C  
public TestMethod() dW3q  
{ ///xx/weblogic60b2_win.exe 1aC ?*,e?  
try{ zLQplw`#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F<'@T,LVc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Ol8ma`}Nq3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j5lSu~  
fileFetch.start(); m791w8Vr  
} L;a> J  
catch(Exception e){e.printStackTrace ();} <"|BuK  
~HbZRDcJc  
B(<;]  
} ekB!d  
>P7|-bV  
P4vW.|@  
public static void main(String[] args) [[{y?-U  
{ tx=~bm"*?  
new TestMethod(); JFw<Po,MEa  
} k_)H$*  
} ^rd]qii"  
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