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http断点续传简单实现(java)

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/* Vb!O8xV4;+  
**SiteFileFetch.java ZzcPiTSO  
*/ gn)R^  
package NetFox; ){P^P!s$  
import java.io.*; _ym"m,,7?  
import java.net.*; zkexei4^<  
kRlA4h1u_$  
{kL&Rv%'  
public class SiteFileFetch extends Thread {  3-|3`(  
=6\LIbO  
.z-UOyer  
SiteInfoBean siteInfoBean = null; //文件信息Bean UpfZi9v?W  
long[] nStartPos; //开始位置 g_aCHEFBv  
long[] nEndPos; //结束位置 W5SNI>|E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vHcqEV|P/n  
long nFileLength; //文件长度 `PlOwj@u0`  
boolean bFirst = true; //是否第一次取文件 {^mKvc  
boolean bStop = false; //停止标志 S6sq#kcH  
File tmpFile; //文件下载的临时信息 #U ASH&  
DataOutputStream output; //输出到文件的输出流 pRi<cO  
C6jR=@42Q  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) zN!j%T.e  
public SiteFileFetch(SiteInfoBean bean) throws IOException BStk&b  
{ Qxa{UQh}9  
siteInfoBean = bean; D4Etl5k  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (=c1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); h@1!T  
if(tmpFile.exists ()) q0./O|Dj   
{ .H~YI  
bFirst = false; 7\Fs=\2l+'  
read_nPos(); b>11h  
} fS=hpL6]@  
else O{]9hm(tN  
{ tFM$#JN  
nStartPos = new long[bean.getNSplitter()]; 57Z-  
nEndPos = new long[bean.getNSplitter()]; h`Tz5% n  
} L/Vx~r`P  
(9C<K<  
Kat&U19YH  
7L3ik;>  
} ;Ii1B{W  
_#C()Ro*P  
%j+xgX/&  
public void run() :P+\p=  
{ %J~WC$=Qv  
//获得文件长度 p&Ed\aQ%z;  
//分割文件 _O]xey^r  
//实例FileSplitterFetch :50b8  
//启动FileSplitterFetch线程 p2 %  
//等待子线程返回 )uheV,ZnY  
try{ }}r> K}  
if(bFirst) +TJ EG?o  
{ GP a`e  
nFileLength = getFileSize(); PaWr[ye  
if(nFileLength == -1) $`J_:H%  
{ X}A'Cg0y  
System.err.println("File Length is not known!"); t ^SzqB  
} eu#'SXSC F  
else if(nFileLength == -2) _Z Y\,_  
{ w$fJ4+  
System.err.println("File is not access!"); zpjqEEY;  
} =#xK=pRy;  
else e0HfP v_  
{ F0lOlS   
for(int i=0;i<nStartPos.length;i++) F]+~x/!  
{ ej(ikj~j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <AoXEu D  
} @n+=vC.xO  
for(int i=0;i<nEndPos.length-1;i++) ?cy4&]s  
{ @It>*B yB.  
nEndPos = nStartPos[i+1]; #,NvO!j<4  
} z=Cr7-  
nEndPos[nEndPos.length-1] = nFileLength; mUoIJ3fv_,  
} 5:.{oSy7n  
} =O$M_1lp  
|j~lkzPnV  
~bK9R 0|<  
//启动子线程 p&b5% 4P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; PnYBy| yl  
for(int i=0;i<nStartPos.length;i++) H17-/|-;0!  
{ 7'lZg<z{~j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2kh"8oQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), m#7*:i&@Y  
nStartPos,nEndPos,i); }6u2*(TmD  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8|^CK|m6*  
fileSplitterFetch.start(); {*m?Kc7k  
} SPkn 3D6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ipE ]}0q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MXtkP1A `  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3'`dFY,  
nEndPos = " + nFileLength); ??&<k   
// fileSplitterFetch[nPos.length-1].start(); 3G}AH E4  
5Wx~ZQZ  
aHzHvl  
//等待子线程结束 wq!iV |  
//int count = 0; q(M:QWA q  
//是否结束while循环 <%?#AVU[  
boolean breakWhile = false; o4y']JSN  
~FU@wV^   
d^E [|w ;  
while(!bStop) j]rz] k  
{ uBrMk  
write_nPos(); DGESba\2+  
Utility.sleep(500);  ;q>9W,jy  
breakWhile = true; zCaT tb|@  
XzIx:J6  
=n(3o$r(  
for(int i=0;i<nStartPos.length;i++) TI|/u$SJ<Z  
{ PJ4(}a  
if(!fileSplitterFetch.bDownOver) @~td`Z?1 y  
{ *Mc7f?H  
breakWhile = false; 0MF}^"R  
break; c]k*}W3T  
} _ QOZ sEe  
} $.%rAa_H  
if(breakWhile)  AnBJ(h  
break; G\d$x4CVGc  
I0'WOV70  
4'1m4Ugg  
//count++; !U%T&?E l  
//if(count>4) KJn!Ap  
// siteStop(); e.d #wyeX  
} bpAv1udX-W  
W!Gdf^Yy<  
(.Y/  
System.err.println("文件下载结束!"); T#@lDpO  
} y[};J vk  
catch(Exception e){e.printStackTrace ();} K>:]Bx#F7  
} xgu `Q`~  
cf_|nL#9  
#18FA|   
//获得文件长度 d~J-|yyT  
public long getFileSize() O Wp%v_y]  
{ B5%n(,Lx  
int nFileLength = -1; <6TT)t<h  
try{ 2-*V=El  
URL url = new URL(siteInfoBean.getSSiteURL()); q/9H..6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^ <`(lyph  
httpConnection.setRequestProperty("User-Agent","NetFox"); Jb_1LZ) ]  
`O?T.p)   
Uh eC  
int responseCode=httpConnection.getResponseCode(); oTjyN\?H  
if(responseCode>=400) 2NGe C0=  
{ E_z;s3AXQ  
processErrorCode(responseCode); uQ$^;Pr  
return -2; //-2 represent access is error #65^w=Sp}  
} ? 8aaD>OR$  
B_`y|sn  
~T7B$$  
String sHeader; +gd2|`#  
NH<gU_s8{9  
qVqRf.-\  
for(int i=1;;i++) u|#>32kV  
{ /&#XhrT  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); lA(Q@yEW  
//Utility.log(in.readLine()); $q?$]k|M`  
sHeader=httpConnection.getHeaderFieldKey(i); Wm~` ~P  
if(sHeader!=null) lH^^77"4Qo  
{ %.v{N6  
if(sHeader.equals("Content-Length")) DhLqhME53  
{ 85:NFa@J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %sBAl.!BN  
break; &.13dq  
} s'aip5P  
} wFh8?Z3u_  
else [D "t~QMr  
break; Y}*\[}l:&x  
} 'n QVj  
} o{b=9-V  
catch(IOException e){e.printStackTrace ();} EJ}!F?o  
catch(Exception e){e.printStackTrace ();} N]EcEM#  
-{XRA6  
O`Gs S{$sS  
Utility.log(nFileLength); l- pe4x  
s&kQlQ=  
5<pftTcZ  
return nFileLength; kv,%(en]  
} mP38T{  
Jb)#fH$L  
YYEJph@06q  
//保存下载信息(文件指针位置) lE8&..~l$+  
private void write_nPos() qSqI7ptA\  
{ keW~ NM  
try{ PP~rn fE  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -4rDbDsr  
output.writeInt(nStartPos.length); kd:$oS_*s  
for(int i=0;i<nStartPos.length;i++) 1be %G [*  
{ 1axQ)},o@p  
// output.writeLong(nPos); Ab%;Z5$fr  
output.writeLong(fileSplitterFetch.nStartPos); jCAC `  
output.writeLong(fileSplitterFetch.nEndPos); 4(neKr5\#  
} r)9Dy,  
output.close(); unJid8Lo  
} 87%*+n:?*  
catch(IOException e){e.printStackTrace ();} EpS(o>'  
catch(Exception e){e.printStackTrace ();} jc[_I&Oc_  
} +x? #DH-  
$8USyGi3J  
aV o;~h~  
//读取保存的下载信息(文件指针位置) *%w6 9#D  
private void read_nPos() Ut-B^x)gl  
{ U-k+9f 0  
try{ UX3BeUi.)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,:fl?x.X  
int nCount = input.readInt(); $&s=68  
nStartPos = new long[nCount]; [3l*F  
nEndPos = new long[nCount]; CM)Q&:  
for(int i=0;i<nStartPos.length;i++) g*)K/Z0pJ$  
{ zl-2$}<a  
nStartPos = input.readLong(); cfox7FmW  
nEndPos = input.readLong(); K3uG2g(>2  
} oRKEJ Nps  
input.close(); KIA 2"KbjG  
} jV#ahNq;  
catch(IOException e){e.printStackTrace ();} n?\ nn3  
catch(Exception e){e.printStackTrace ();} Mypc3  
} &R|/t :DN  
M<SdPC(+  
&1l=X]%  
private void processErrorCode(int nErrorCode) IKMeJ(:S  
{ WwF~d+>|C  
System.err.println("Error Code : " + nErrorCode); )15Z#`x  
} ONNpiK-  
,:~0F^z  
{U 'd}Q  
//停止文件下载 4Wy <?O2  
public void siteStop() IX: 25CEI2  
{ 2)#K+O3c  
bStop = true; ms($9Lv/  
for(int i=0;i<nStartPos.length;i++) ~^u16z,  
fileSplitterFetch.splitterStop(); Wk:hFHs3  
^JI o? R  
i,V;xB2  
} nJRS.xs  
} ^l^fD t  
//负责部分文件的抓取 J$4wL F3  
**FileSplitterFetch.java R1F5-#?'E  
*/ {7!UQrm<  
package NetFox; `r5 $LaD  
T5Q{{@Q  
+,:du*C  
import java.io.*; c`lJu_  
import java.net.*; (>mI'!4d  
t E` cau  
/&u<TJ4  
public class FileSplitterFetch extends Thread { N=:5eAza  
Wv__ wZ  
`28};B>  
String sURL; //File URL VIP7OHJh  
long nStartPos; //File Snippet Start Position G*S|KH  
long nEndPos; //File Snippet End Position @)kO=E d  
int nThreadID; //Thread's ID DjU9 uZT  
boolean bDownOver = false; //Downing is over SVjl~U-^  
boolean bStop = false; //Stop identical ,+qVu,  
FileAccessI fileAccessI = null; //File Access interface 22kpl)vbU  
WwC 5!kZ  
2([2Pb3<"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException w;Q;[:y  
{ cPgfTT  
this.sURL = sURL; 2&+#Vsm`V  
this.nStartPos = nStart; Auy_K?he]  
this.nEndPos = nEnd; T081G`li  
nThreadID = id; J7C4V'_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P5lqSA{6  
} r]W  
Oz|K8p  
79\Jx iSB  
public void run() zkTp`>9R  
{ |Iu npZV  
while(nStartPos < nEndPos && !bStop) %{3 aW>yx  
{ awv De  
nR4y`oP+  
tb :L\A^:  
try{ l5+gsEux]  
URL url = new URL(sURL); ?ER-25S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {]z4k[;.h  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9}B`uJ  
String sProperty = "bytes="+nStartPos+"-"; /(O$(35  
httpConnection.setRequestProperty("RANGE",sProperty);  g PAX4'  
Utility.log(sProperty); {;2vmx9  
]"c+sMW  
USN8N (  
InputStream input = httpConnection.getInputStream(); }HE6aF62O  
//logResponseHead(httpConnection); sC[yI Up  
JFgoN,xn  
{0! ~C=P  
byte[] b = new byte[1024]; bYz&P`o}  
int nRead; =A Vg Iv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~&\ f|%  
{ a[lY S{  
nStartPos += fileAccessI.write(b,0,nRead); x8;`i$  
//if(nThreadID == 1) '0$?h9"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b3wM;jv  
} {JV@"t-X3"  
o ]IjK  
IVr 2y8K  
Utility.log("Thread " + nThreadID + " is over!"); >NB?& |  
bDownOver = true; nm7;ieMfr  
//nPos = fileAccessI.write (b,0,nRead); H:p Z-v*  
} fYE(n8W3  
catch(Exception e){e.printStackTrace ();} i{D=l7j|w  
} +GsWTEz   
} jGrN\D?h  
B2Xn?i3 l  
@"T"7c?Cv  
//打印回应的头信息 i(? ,6)9  
public void logResponseHead(HttpURLConnection con)  FgL,k  
{ +n}$pM|NKU  
for(int i=1;;i++) PSawMPw  
{ ;n\= R 5.  
String header=con.getHeaderFieldKey(i); Y!6/[<r$~k  
if(header!=null) s4_/&h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?PTk1sB  
Utility.log(header+" : "+con.getHeaderField(header)); _Lw OOZj  
else vIvVq:6_3  
break; EQqx+J&!  
} kY]W Qu  
} PpLU  
[sW.CK= 3  
Og;-B0,A  
public void splitterStop() EBtLzbj  
{ yfU<UQ!1  
bStop = true; Yxv9  
} = 07Gy,=i  
(;VVC Aoy  
`Q+moX  
} kj+#Tn F-  
VL[)[~^  
gPC*b+  
/* LJX-AO.4  
**FileAccess.java :Q+5,v-c  
*//文件访问(定位,写) I ];M7  
package NetFox; ylKmj]A  
import java.io.*; 9+,R`v  
1Y_w5dU  
X0{/ydG F8  
public class FileAccessI implements Serializable{ 1_$xSrwcF  
nN$Y(2ZN  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8Ry74|`=R  
RandomAccessFile oSavedFile; 5>6PH+Oq  
long nPos; M5T9JWbN  
xoB},Xl$D  
k%[3Q>5iM  
public FileAccessI() throws IOException xUF_1hY  
{ %AF5=  
this("",0); ,wKe fpV;5  
} "l={)=R  
va f&X]p  
)'l*Tl  
public FileAccessI(String sName,long nPos) throws IOException 1>Q{Gs^  
{ b]E|*  
oSavedFile = new RandomAccessFile(sName,"rw"); ?)'~~ @NkH  
this.nPos = nPos; 39 {{7(hh  
oSavedFile.seek(nPos); B7\k< Nit0  
} k7tYa;C  
.^) UO  
2!N8rHRt  
public synchronized int write(byte[] b,int nStart,int nLen) J==SZ v  
{ Oo?,fw  
int n = -1; 2/,0iwj-  
try{ %hlspI(J  
oSavedFile.write(b,nStart,nLen); M>jtFP <S  
n = nLen; 3Q/#T1@  
} {;2i.m1  
catch(IOException e) $- +/$!  
{ ~-a'v!  
e.printStackTrace (); wPbkUVO  
} #6Xs.*b5C  
P7B:%HiAx  
Qy#)Gxp  
return n; wV?,Z!\Z  
} ~.PP30 '  
GFSt<k)  
[NnauItI  
} `SO|zz|'  
M(|   
S{',QO*D6  
/* G0n'KB  
**SiteInfoBean.java >#+IaKL7  
*/ _<ut)G^9  
package NetFox; g%[n4  
/8@m<CW2Y  
J H.K.C(  
public class SiteInfoBean { EoX_KG{  
dQy>Nmfy  
wx=0'T-[  
private String sSiteURL; //Site's URL =1dI>M>tm  
private String sFilePath; //Saved File's Path 5)1+~B  
private String sFileName; //Saved File's Name ^EVc95|Z  
private int nSplitter; //Count of Splited Downloading File {Hr$wa~  
wLuv6\E  
_eLWQ|6Fx  
public SiteInfoBean() 59(U`X  
{//nSplitter的缺省值为5 QD{:vG g  
//default value of nSplitter is 5 `h;k2Se5  
this("","","",5); 9^P2I)aD  
} ! BU)K'mj  
 Do?P<x o  
nW\(IkX\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;%J5=f%z)  
{ R)!`JKeO/  
sSiteURL= sURL; t?;T3k[RM  
sFilePath = sPath; 4X NxI1w)  
sFileName = sName; [%HIbw J  
this.nSplitter = nSpiltter; ,]R8(bD)  
WUAJjds  
fbZibcQ%k  
} OH<?DcfeL  
IL7`0cN(  
jW*1E *"  
public String getSSiteURL() 'f?.R&sCA  
{ JU0]Wq<^[  
return sSiteURL; %R_{1GrL'c  
} [n,?WwC  
EruP  
,KW;2t*IQ@  
public void setSSiteURL(String value) :lcea6iO  
{ 9T2xU3UyY  
sSiteURL = value; ?y},,  
} (k-YI{D3  
uK*Nu^  
BpAB5=M0  
public String getSFilePath() B7Ntk MK  
{ Z\X'd_1!  
return sFilePath; qZ2&Xw.{1  
} Bt^K]F\  
~>ME'D~  
%@& a7JOL  
public void setSFilePath(String value) {I%y;Aab8  
{ jigs6#  
sFilePath = value; Iyk6=&?j  
} LR)& [{Kk  
U` R;P-  
Ru%|}sfd  
public String getSFileName() `ZHP1uQ<  
{ <v]9lw'  
return sFileName; E|Bd>G  
} $]d*0^J 6  
^Uw[x\%#gD  
T!q_/[i~7  
public void setSFileName(String value) o|S)C<w  
{ <MD;@_Nz\  
sFileName = value; ru.5fQ U  
} 74vmt<Q  
NlR"$  
:x>T}C<Y  
public int getNSplitter() #Olg(:\  
{ <SXZx9A!  
return nSplitter; H^c0Kh+  
} X\GM/A  
fhpX/WE6  
V: p)m&y6  
public void setNSplitter(int nCount) gqiXmMm:9  
{ _pDjg%A>n  
nSplitter = nCount; =(U/CI  
} K\=8eg93Z  
} -R+zeu(e'  
;'kI/(;;C  
T@+ClZi  
/* OS7R Qw1  
**Utility.java 1 0N,?a  
*/ B< ;==|  
package NetFox; a#(U2OP  
=TcOnQj  
ki\uTD`mf  
public class Utility { 3l:QeZ  
/J%do]PDl  
2YQ#-M  
public Utility() vb=CFV#  
{ VZxTx0: ,  
~^o=a?L`<  
_,; %mK  
} o\4t4}z~'f  
_'iDF  
//线程睡眠 HFh /$VM  
public static void sleep(int nSecond) l)}t,!M6  
{  b;vNq  
try{ /5a;_  
Thread.sleep(nSecond); tjzA)/T,4  
} }OKL z.5  
catch(Exception e) XCPb9<L  
{ '"O&J}s;  
e.printStackTrace (); `"<2)yq?  
} p]f&mBO*  
} MQw9X  
u^Sv#K X  
//日志 }""p)Y&  
public static void log(String sMsg) XeUprN  
{ 8fO8Dob]\Y  
System.err.println(sMsg); XL"=vbD  
} v&0d$@6/U  
|^5/(16  
az(5o  
public static void log(int sMsg) i.@*t IK  
{ _EKF-&Q6  
System.err.println(sMsg); c cr" ep  
} zGs|DB  
} z[ #6-T &  
# cWHDRLX  
+{>.Sk'$  
/* _"f<Ol[!  
**TestMethod.java <q6`~F~|  
*/ 0/A-#'>  
package NetFox; 2ij/N%l  
R 7K  
wXCyj+XB*  
public class TestMethod { {visv{R<  
}u^:MI  
-N^ =@Yx)  
public TestMethod() ' o=E!?  
{ ///xx/weblogic60b2_win.exe ~I)uWo  
try{ @a;sV!S{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9/46%=&]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); d=n h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cyc>_$/;1  
fileFetch.start(); sFx$>:$  
} %Rn:G K  
catch(Exception e){e.printStackTrace ();}  z\$;'  
)kA2vX^=Z  
59MR|Jt  
} cju@W]!  
\]a uSO  
PJwEA  
public static void main(String[] args) .HDebi  
{ "o==4?*L  
new TestMethod(); =tq7z =k  
} L w*1 .~  
} {{zua- F  
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