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http断点续传简单实现(java)

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/* rl&.|;5uH;  
**SiteFileFetch.java ^FVmP d*1  
*/ #{^qBP[  
package NetFox; uBn35%  
import java.io.*; M{jq6c  
import java.net.*; \=`jo$S  
4i5b.b U$  
HgBu:x?&  
public class SiteFileFetch extends Thread { _ n1:v~  
4tx6h<L#s  
 K V  
SiteInfoBean siteInfoBean = null; //文件信息Bean #0\* 8 6  
long[] nStartPos; //开始位置 "Nz@jv?  
long[] nEndPos; //结束位置 "WO0 rh`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %Pj}  
long nFileLength; //文件长度 Zb|a\z8?  
boolean bFirst = true; //是否第一次取文件 ,nGQVb   
boolean bStop = false; //停止标志 ^ 4Ff8Y  
File tmpFile; //文件下载的临时信息 /L5:/Z  
DataOutputStream output; //输出到文件的输出流 R@/"B?`(f  
5h Dy62PRr  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) [1ClZ~f  
public SiteFileFetch(SiteInfoBean bean) throws IOException LafBf6wds  
{ G;/l[mvh,  
siteInfoBean = bean; +Z86Qz_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #};Zgixo$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8xG"hJR  
if(tmpFile.exists ()) x5Fo?E  
{ kHhku!CH  
bFirst = false; x25zk4-  
read_nPos(); Df:/r%  
} $|T Lt{ K  
else  Zy8tI#  
{ Jf\`?g3#  
nStartPos = new long[bean.getNSplitter()]; wu &lG!#  
nEndPos = new long[bean.getNSplitter()]; i\gt @  
} %6m' |(-  
E*fa&G~s )  
o^//|]H3Y  
wzJdS}Yy!y  
} X8?@Y@  
;ceg:-Zqo  
(I'{ pF)  
public void run() `PvS+>q  
{ moh,aB#  
//获得文件长度 "r3h+(5  
//分割文件 rmtCCPF?0  
//实例FileSplitterFetch W}}ZP];  
//启动FileSplitterFetch线程 B., BP  
//等待子线程返回 "a33m:]J  
try{ qPWf=s7!  
if(bFirst) a" T+CA  
{ csxn" Dz\  
nFileLength = getFileSize(); -1`}|t;  
if(nFileLength == -1) {;zHkmx  
{ _@gg,2 u-  
System.err.println("File Length is not known!"); {?EmO+![}  
} k B4Fz  
else if(nFileLength == -2) i[{*(Y$L  
{ }d iE'  
System.err.println("File is not access!"); Wa.!eAe}  
} ?~#[ cx  
else -yg;,nCg  
{ w'VuC82SZ  
for(int i=0;i<nStartPos.length;i++) M"u=)CT  
{ pF8:?p['z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); E}a.qM'  
} !?Y71:_!  
for(int i=0;i<nEndPos.length-1;i++) 7!FiPH~kM  
{ D`X<b4e8/  
nEndPos = nStartPos[i+1]; ^P/OHuDL  
} QZa^Cng~  
nEndPos[nEndPos.length-1] = nFileLength; PxvxZJf$@  
} -vk/z+-^!  
} aG4 ^xOD  
zb02\xvf  
@\xEK5SG  
//启动子线程 I,,SR"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [;F!\B-  
for(int i=0;i<nStartPos.length;i++) ,1lW`Krx  
{ /h`gQyGuY  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x_?K6[G&}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @T>^ >  
nStartPos,nEndPos,i); SkVah:cF-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ) =x4+)9  
fileSplitterFetch.start(); >9#) obw  
} M(C}2.20  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2Dvq3VbiO"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); R%)F9P$o  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8oRq3"  
nEndPos = " + nFileLength); ]VtP7 Y  
// fileSplitterFetch[nPos.length-1].start(); 5nceOG8  
u(? U[pe[  
0oBAJP  
//等待子线程结束 B,Tv9(sv  
//int count = 0; Fl{~#]  
//是否结束while循环 /l3Oi@\  
boolean breakWhile = false; ;p fN  
tI#65ox#  
0JR)-*  
while(!bStop) '.S02=/  
{ -ik((qx_  
write_nPos(); l 6aD3?8LN  
Utility.sleep(500); BePb8 k<y  
breakWhile = true; Dvl\o;  
sE|8a  
Z.unCf3Q  
for(int i=0;i<nStartPos.length;i++) 9(vp`Z8B4  
{ +ek6}f#  
if(!fileSplitterFetch.bDownOver) %(POC=b#[  
{ iS"6)#a72  
breakWhile = false; DZb0'+jQ  
break; m6 xbO  
} }XpZgd$  
} ,kYX|8SO  
if(breakWhile) mRGr+m  
break; SNSoV3|k-  
*p0n^XZ% ?  
6Iz!_  
//count++; HxL uJ  
//if(count>4) 7*Zm{r@u  
// siteStop(); <pS#wTsN4%  
} F* Yx1vj  
(R RRG;*n#  
]_|%!/_  
System.err.println("文件下载结束!"); 4Sdj#w  
} /; 21?o  
catch(Exception e){e.printStackTrace ();} ^U,C])n  
} <+b~E,  
3!#FG0Z   
|N 2r?b/g  
//获得文件长度 a8k`Wog  
public long getFileSize() 1 un!  
{ Pmr'W\aIR  
int nFileLength = -1; q1r-xsjV=  
try{ wXBd"]G)C  
URL url = new URL(siteInfoBean.getSSiteURL()); zqI|VH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j0 Os]a  
httpConnection.setRequestProperty("User-Agent","NetFox"); JlEfUg#*  
j{=}?+M  
"15frr?  
int responseCode=httpConnection.getResponseCode(); `G*fx=N  
if(responseCode>=400) Tpkt'|8  
{ #Wb4*  
processErrorCode(responseCode); 5,|{|/  
return -2; //-2 represent access is error NPa4I7`A  
} puEu)m^  
la$%%@0/  
2t{Tz}g*  
String sHeader; rploQF~OFF  
nU#K=e =W  
37M,Os1(  
for(int i=1;;i++) X .K*</(g  
{ { W5 _KX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |&bucG=  
//Utility.log(in.readLine()); ~rAcT6#  
sHeader=httpConnection.getHeaderFieldKey(i); X~\O]  
if(sHeader!=null) -ni@+Dy  
{ >29c[O"[  
if(sHeader.equals("Content-Length")) 6D{70onY+  
{ ~= otdJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); k@[[vj|W  
break; 7s}F`fjKP  
} nKTi"2dm  
} " Z dI~  
else 'S#^ 70kt  
break; zP c54 >f  
} Ak O-PL  
} yy3`E}vX7  
catch(IOException e){e.printStackTrace ();} e\*(F3r  
catch(Exception e){e.printStackTrace ();} eOZ~p  
tWTC'Gx-J  
e?]HNy  
Utility.log(nFileLength); xz +;1JAL3  
7.kH="@  
?1eu9;q\*  
return nFileLength; ~)ysEZl  
} KyqP@ {  
rQpQ qBu  
s]D1s%Mx  
//保存下载信息(文件指针位置) '#QZhz(+  
private void write_nPos() {?3i^Q=V  
{ ,1v FX$  
try{ W(.svJUgb.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z38Pi  
output.writeInt(nStartPos.length); ._.Qf<7  
for(int i=0;i<nStartPos.length;i++) ;9Wimf]G,E  
{ J10&iCr{r*  
// output.writeLong(nPos); #wh[F"zX  
output.writeLong(fileSplitterFetch.nStartPos); 0p\Kf(|E*6  
output.writeLong(fileSplitterFetch.nEndPos); GW.Y= S  
} AD6 b  
output.close(); 'BVI^H4  
} {L M Q  
catch(IOException e){e.printStackTrace ();}  (8 /&  
catch(Exception e){e.printStackTrace ();} 7Q&S [])  
} #!r>3W&  
WO^]bR  
J*^ i=y  
//读取保存的下载信息(文件指针位置) P(L iH  
private void read_nPos() kn&BGYt  
{ 6/Z_r0^O  
try{ ]XYD2fR2qA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i&)OJy  
int nCount = input.readInt(); ^Q!A4 qOQ  
nStartPos = new long[nCount]; Enp;-wG:-  
nEndPos = new long[nCount]; koj*3@\p/  
for(int i=0;i<nStartPos.length;i++) _+%p!!  
{ jd}~#:FUr*  
nStartPos = input.readLong(); tS,AS,vy]  
nEndPos = input.readLong(); 1IK*j +%  
} b~TTz`HZ  
input.close(); ?U2 'L2y  
} |"eC0u  
catch(IOException e){e.printStackTrace ();}  SxX  
catch(Exception e){e.printStackTrace ();} ;9vY5CxzC  
} vOtILL6  
5/HkhT yj  
81)i>]  
private void processErrorCode(int nErrorCode) CUaL  
{ JDO n`7!w  
System.err.println("Error Code : " + nErrorCode); 4-C'2?  
} W/%9=g$m  
OA[fQH#{lX  
&NI\<C7_Gw  
//停止文件下载 zN\C  
public void siteStop() veS) j?4  
{ !0v3Lu ~j  
bStop = true; bPuO~#iN~  
for(int i=0;i<nStartPos.length;i++) M{YN^ Kk  
fileSplitterFetch.splitterStop(); ;i ?R+T  
}%0X7'  
q 'uGB fE.  
} g5*?2D}dqX  
} 'GLpSWL+*  
//负责部分文件的抓取 G P`sOPr  
**FileSplitterFetch.java TT&%[A+  
*/ d?/>Qqw:#  
package NetFox; *mW2vJ/B  
TW1#'G_#  
l}D /1~d  
import java.io.*; ( F4c0  
import java.net.*; $JiypX^DOP  
?5j~"  
:_o^oi7G  
public class FileSplitterFetch extends Thread { 0*AXd=)"*  
| vxmgX)  
cPg{k}9Tvy  
String sURL; //File URL ,z> w^_  
long nStartPos; //File Snippet Start Position *thm)Mn  
long nEndPos; //File Snippet End Position wv Mp~  
int nThreadID; //Thread's ID P5lk3Zg '  
boolean bDownOver = false; //Downing is over isFxo,R9r  
boolean bStop = false; //Stop identical bP4}a!t+n  
FileAccessI fileAccessI = null; //File Access interface 2{B ScI5K  
?^`fPH=  
-_Kw3x  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {~XnmBs  
{ @eq.&{&  
this.sURL = sURL; pfFHuS~  
this.nStartPos = nStart; B_XX)y%V  
this.nEndPos = nEnd; u hB V)Qg  
nThreadID = id; A-YW!BT4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :Vw{ l B  
} F#.ph?W  
8uA!Vrp3  
#WAX&<m  
public void run() (]zi;  
{ -]QP#_   
while(nStartPos < nEndPos && !bStop) o1uM(  
{ s3 VD6xi7  
(D{J|  
Y) l=r^Ap>  
try{ wNmC1HOh  
URL url = new URL(sURL); d;{k,rP6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Bi>]s%zp  
httpConnection.setRequestProperty("User-Agent","NetFox"); V~do6[(  
String sProperty = "bytes="+nStartPos+"-"; Gz(l~!n~a  
httpConnection.setRequestProperty("RANGE",sProperty); ~Bi%8G  
Utility.log(sProperty); 32`Z3-  
pX1Us+%  
[.&n,.k  
InputStream input = httpConnection.getInputStream(); |f(*R_R  
//logResponseHead(httpConnection); $KlaZ>D h  
Fqh./@o  
%.HLO.A  
byte[] b = new byte[1024]; =T1Xfib  
int nRead; Np/vPaAk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F@zTz54t  
{ F_4Et  
nStartPos += fileAccessI.write(b,0,nRead); RF~G{wz  
//if(nThreadID == 1) ;^|):x+O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oe!4ng[  
} ]bYmM@  
}c>vk  
D]N)  
Utility.log("Thread " + nThreadID + " is over!"); k$pND,Ws  
bDownOver = true; kfZ(:3W$  
//nPos = fileAccessI.write (b,0,nRead); <2~DI0pp(  
} >7~,w1t  
catch(Exception e){e.printStackTrace ();} 0Gu?;]GSv  
} "bQi+@  
} 14*6+~38m&  
"yj_v\@4  
1/K1e$r  
//打印回应的头信息 a2/Mf   
public void logResponseHead(HttpURLConnection con) zS h9`F  
{ w\{#nrhYU  
for(int i=1;;i++) 5u3KL A  
{ yB 'C9wEH  
String header=con.getHeaderFieldKey(i); 9}Ge@a<j  
if(header!=null) [JV?Mdzu  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -= izu]Fb,  
Utility.log(header+" : "+con.getHeaderField(header)); /XU=l0u  
else IreY8.FND  
break; 7PBE(d%m  
} =K}T; c  
} iSg0X8J)  
# s7e/GdKb  
GSd:Plc%  
public void splitterStop() Wu(^k25  
{ ,+I]\ZeO  
bStop = true; I5`>XfO)  
} 5)5yH bS  
&xGpbJG  
V`HnFAW  
} e,lLHg  
L 4Z+8*  
(U_HX2f  
/* =6'bGC%c  
**FileAccess.java ck3+A/ !z  
*//文件访问(定位,写) P"]l/  
package NetFox; R0LWuE%eD  
import java.io.*; _*b`;{3  
#kA?*i[T  
\fuz`fK:  
public class FileAccessI implements Serializable{ o=K9\l  
q/d?c Lgl  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B692Mn  
RandomAccessFile oSavedFile; c\&;Xr  
long nPos; v~jm<{={g  
J9DI(`  
-Dy<B  
public FileAccessI() throws IOException LZ.Xcy  
{ u3E =r  
this("",0); &m   GU  
}  + #E?)  
dUl"w`3  
_Hfpizm  
public FileAccessI(String sName,long nPos) throws IOException Z @ef2y;  
{ <W)F{N?  
oSavedFile = new RandomAccessFile(sName,"rw"); 8#- Nx]VM  
this.nPos = nPos; mg@Ol"2  
oSavedFile.seek(nPos); T?6<1nU)  
} %lGOExV%  
*N:0L,8  
vqO#Z  
public synchronized int write(byte[] b,int nStart,int nLen) HavlN}h  
{ u86PTp+  
int n = -1; 9=}[~V n  
try{ lSO$Q]!9  
oSavedFile.write(b,nStart,nLen); w-xigm>{Z  
n = nLen; Vsw:&$  
} MX7Ix{  
catch(IOException e) yWE\)]9  
{ p]/[ji  
e.printStackTrace (); 2FV@ ?x0po  
} "PO8Q  
D6+3f #k6  
~J> ;l s1  
return n; +R HiX!PG  
} :FtV~^Z  
yjH'<  
\_6  
} |yzv o"3  
%#eQN ~  
3 H5  
/* &=$f\O1Ty  
**SiteInfoBean.java N:k>V4oE  
*/ 5U4V_*V  
package NetFox; SK^(7Ws~0  
W*#5Sk  
fjl 9*  
public class SiteInfoBean { _z{9V7n4  
d;wq@ e  
SE@TY32T  
private String sSiteURL; //Site's URL wVnmT94  
private String sFilePath; //Saved File's Path > /Q^.hzd  
private String sFileName; //Saved File's Name zwJ&K;"y(  
private int nSplitter; //Count of Splited Downloading File &FT`z"^  
?wCX:? g  
#\n* Qg4p  
public SiteInfoBean() e@TwZ6l  
{//nSplitter的缺省值为5 ztX$kX:_m  
//default value of nSplitter is 5 |9IOZ>H9  
this("","","",5); {=mGXd`x?l  
} yt="kZ  
.Y?]r6CC/  
,+6u6  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Y,Rr[i"j  
{ QT^b-~^  
sSiteURL= sURL; B@i%B+qCLv  
sFilePath = sPath; 7Re\*[)T  
sFileName = sName; j|K;Yi  
this.nSplitter = nSpiltter; 3o?eUwI}  
2ww H3}  
<!UnH6J.b  
} {z0iWY2Xw  
N#"l82^H*  
C~@m6K  
public String getSSiteURL() Tq?Ai_  
{ x4L3Z__  
return sSiteURL; y_Urzgm(  
} U4K ZPk  
V@-Q&K#  
KA?%1s(kJ  
public void setSSiteURL(String value) h4|}BGO  
{ QSa#}vCp*  
sSiteURL = value; Rk#'^ }  
} ( B\ UZb  
:H m'o}  
7g+T  
public String getSFilePath() ~S;-sxoO0l  
{ }8aqSD<:  
return sFilePath; zb!1o0, J  
} ,f:K)^yD  
J9*;Bqzim  
w(S~}'Sg*P  
public void setSFilePath(String value) /NCN wAj7  
{ ]3f[v:JQ  
sFilePath = value; ]k7%p>c=B  
} {2P18&=  
l/zv >  
pFNU~y'Kf  
public String getSFileName() C5I7\9F)  
{ ~//E'V-  
return sFileName; tJ>>cFx  
} ,-E'059  
n9={D  
KhB775  
public void setSFileName(String value) 6?<lS.s  
{ 9S}rTZkEq  
sFileName = value; ~i?A!  
} z|%Pi J ,  
0{bl^#$f  
ki@C}T5  
public int getNSplitter() &DGz/o  
{ 0,DrVGa  
return nSplitter; >L4F'#I  
} kG!hqj  
d!R+-Fp  
qwj7CIc(  
public void setNSplitter(int nCount) nf"#F@dk  
{ 'hBnV xd&  
nSplitter = nCount; `Tyd1!~  
} 1Xm>nF~  
} Q}lCQK/g  
{._'Q[  
a7ZufB/  
/* /Z^a, %1  
**Utility.java V^[&4  
*/ #vyf*jPr  
package NetFox; aaY AS"/:  
[5p9p1@u{C  
[y'blCb  
public class Utility { bs)wxU`Q*  
Tt~[hC h  
SIrNZ^I  
public Utility() -A w]b} #v  
{ 8o%Vn'^t  
rY^uOrR>j*  
9Q s5e  
} *,lDo9  
L k nK  
//线程睡眠 W)Y`8&,  
public static void sleep(int nSecond) PL$XXj>|:  
{ &>+T*-'  
try{ QH(&Cu,  
Thread.sleep(nSecond); Ii[U%  
} @hg[v`~  
catch(Exception e) L QV@]z&  
{ mm: TR?^  
e.printStackTrace (); k $^/$N  
} K a(B&.  
} ZXYyG`3+  
zi6J|u  
//日志 v0 :n:q  
public static void log(String sMsg) `f~bnL  
{ #`|Nm3b  
System.err.println(sMsg); T]&?^QGAZ  
} Y(7&3+'K  
dNt^lx  
uVU)LOx  
public static void log(int sMsg) ' abEY  
{ EEZ~Bs}d  
System.err.println(sMsg); ,S`n?.&& 7  
} IWq\M,P  
} t.;._'  
M]{~T7n-  
Jaw1bUP!oK  
/* pI K:$eN!/  
**TestMethod.java B(s^(__]  
*/ PsNrCe%e  
package NetFox; Ij4q &i"  
-avxH?;?7  
A? B +  
public class TestMethod { Q<V1`e  
u,8)M' UU  
'1 2*'Q+{+  
public TestMethod() Het"x  
{ ///xx/weblogic60b2_win.exe tb~E.Lm\  
try{ +?"F=.SZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); M}11 tUl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *> nOL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Gy):hGgN  
fileFetch.start(); &K'*67h  
} %zGv+H?  
catch(Exception e){e.printStackTrace ();} l59\Lo:  
AeEdqX)  
|33t5}we  
} L{jx'[C  
Jb*QlsGd  
6ZHeAb]"  
public static void main(String[] args) iLBORT !;  
{ ]}b  
new TestMethod(); F5x*#/af  
} e'$[PF  
} Rjq\$aY}%  
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