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http断点续传简单实现(java)

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/* ,>^6ztM  
**SiteFileFetch.java Y<vsMf_U  
*/ YR{%p Zp  
package NetFox; ?y@RE  
import java.io.*; NPL(5@  
import java.net.*; +@QN)ZwVy  
6Wm`Vj(s  
:RH0.5)  
public class SiteFileFetch extends Thread { DeAi'"&  
.[1"3!T  
u9:+^F+  
SiteInfoBean siteInfoBean = null; //文件信息Bean >brf7h  
long[] nStartPos; //开始位置 Ev R6^n/  
long[] nEndPos; //结束位置 9<9 c^2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Bj ~bsT@a.  
long nFileLength; //文件长度 uP:Y[$O  
boolean bFirst = true; //是否第一次取文件 <#hltPyh  
boolean bStop = false; //停止标志 kbxy^4"X  
File tmpFile; //文件下载的临时信息 @LzqQ [  
DataOutputStream output; //输出到文件的输出流 ,.cNs5 [t  
i09w(k?  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 4|Wg lri  
public SiteFileFetch(SiteInfoBean bean) throws IOException H.D1|sU  
{ 9 NO^ '  
siteInfoBean = bean; !w!}`|q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); qOusO6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); h|MTE~   
if(tmpFile.exists ()) lDQ'  
{ RO([R=.`/  
bFirst = false; Z]1=nSv  
read_nPos(); eu]t.Co[X  
} PMdvBOtS`  
else P?y3YxS  
{ D};zPf@!p  
nStartPos = new long[bean.getNSplitter()]; ZwV`} 2{  
nEndPos = new long[bean.getNSplitter()]; C{i9~80n  
} gm-I)z!tz  
b&y"[1`  
DRBRs-D  
+0,{gDd+  
} u]B15mT?  
=*AAXNs@3  
y}fF<qih'>  
public void run() yN0!uzdW*  
{ ,<^7~d{{3m  
//获得文件长度 UogkQ& B  
//分割文件 c\n&Z'vK  
//实例FileSplitterFetch V>{G$(v$  
//启动FileSplitterFetch线程 \8~P3M":c  
//等待子线程返回 H9x,C/r,  
try{ q*Hf%I"  
if(bFirst) w/L^w50pt  
{ |r]f2Mrm  
nFileLength = getFileSize(); D*>EWlZ   
if(nFileLength == -1) O:=%{/6&D  
{ n9;z=   
System.err.println("File Length is not known!"); p m4g),s  
} \WDL?(G<  
else if(nFileLength == -2) $Vi[195]2  
{ T,Bu5:@#  
System.err.println("File is not access!"); =aWj+ggd@  
} [|=#~(yYQ  
else ,s%1#cbR  
{ e~#"#?  
for(int i=0;i<nStartPos.length;i++) Nn"[GB  
{ IZ$7'Mo86  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); kHO2&"6  
} +@'{  
for(int i=0;i<nEndPos.length-1;i++) g1je':  
{  t8 "*j t  
nEndPos = nStartPos[i+1]; )YDuq(g&  
} RG'Ft]l92N  
nEndPos[nEndPos.length-1] = nFileLength; %TY;}V59b  
} fQ\nK H~  
} !n=?H1@  
B@:c 8}2.  
+0w~Skd,  
//启动子线程 a?zn>tx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >q'xW=Y j\  
for(int i=0;i<nStartPos.length;i++) `]Uu`b  
{ 69 PTo  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'f#i@$|]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +<G |Ru-  
nStartPos,nEndPos,i); p19[qy~.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @>wD`<U|  
fileSplitterFetch.start(); j|`6[93MG  
} sHqs)@D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fp jy[$8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *^BW[C/CTR  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6m.ChlO/  
nEndPos = " + nFileLength); "[PxLq5  
// fileSplitterFetch[nPos.length-1].start(); Zu4|1 W  
L|y4u;-Q  
|WopsV %  
//等待子线程结束 pjC2jlwm*  
//int count = 0; b7 pD#v  
//是否结束while循环 1]yOC)u"i  
boolean breakWhile = false; >-2eZ(n)"  
[79 eq=  
(,5oqU9s@  
while(!bStop) Mp*S+Plp  
{ Wc}opp  
write_nPos(); DFgr,~  
Utility.sleep(500); uHBEpqC%  
breakWhile = true; kOe %w-_  
+d[A'&"  
*]ROUk@K=  
for(int i=0;i<nStartPos.length;i++) bv.DW,l%'  
{ QT1(= wK3  
if(!fileSplitterFetch.bDownOver) ugtzF  
{ }Yi)r*LI3  
breakWhile = false; dmq<vVxC  
break; tSST.o3  
} C~do*rnM^  
} p!+7F\  
if(breakWhile) L<kIzB !  
break; e&Z\hZBb  
T;cyU9  
Wq bfZx  
//count++; g/)$-Z)Nu  
//if(count>4) 59?@55  
// siteStop(); -#=y   
} .k{omr&Dy5  
|G2hm8 Y  
\JJ>y  
System.err.println("文件下载结束!"); "2>I?  
} 0jS"PH?[  
catch(Exception e){e.printStackTrace ();} i\P?Y(-{  
} - nWs@\  
:NB,Dz+i  
8+m[ %5lu  
//获得文件长度 Qfhhceb6#J  
public long getFileSize() U=?hT&w\S  
{ @WppiZ$  
int nFileLength = -1; R&z)  
try{ qz|`\^  
URL url = new URL(siteInfoBean.getSSiteURL()); )+^1QL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); omxBd#;F$  
httpConnection.setRequestProperty("User-Agent","NetFox"); T&?0hSYt  
z|Z<S+=f  
#n=b*.  
int responseCode=httpConnection.getResponseCode(); kzA%.bP|  
if(responseCode>=400) U'pm5Mc\q  
{ Zk#^H*jgx  
processErrorCode(responseCode); tEz6B}  
return -2; //-2 represent access is error P;&rh U^[  
} <Tq&Va_w  
0nkon3H  
-rU~  
String sHeader; 2gn*B$a  
ryz [A:^G  
#z|\AmZ\  
for(int i=1;;i++) ~[@Gj{6p0  
{ ^y@ RfM=A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~<M/<%o2*  
//Utility.log(in.readLine()); sGNVZx  
sHeader=httpConnection.getHeaderFieldKey(i); dg%Orvuz  
if(sHeader!=null) us&!%`  
{ 6E9y[ %+  
if(sHeader.equals("Content-Length")) )P6n,\  
{ NLe+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]J^ 9iDTTA  
break; .s4hFB^n  
} U] 2fV|Hn  
} Jjb(lW  
else 9aLS%-x!+  
break; &G5=?ub  
} jB8n\8 Bs  
} `={s*^Ta  
catch(IOException e){e.printStackTrace ();} zNE"5  
catch(Exception e){e.printStackTrace ();} %G%##wv:  
*7"R[!9  
> ,L'A;c}  
Utility.log(nFileLength); Oeo:V"  
H].G%,2'  
Onr#p4UT  
return nFileLength; Da)rzr|}>3  
} Zk+J=Cwq}  
NO4V{}?a  
xl%!7?G|$>  
//保存下载信息(文件指针位置) s52c`+  
private void write_nPos() x 4SI TY  
{ lO/<xSjNd  
try{ By=/DVm)=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); qyP|`Pm4  
output.writeInt(nStartPos.length); zy(i]6  
for(int i=0;i<nStartPos.length;i++) P)fv:a  
{ b\zRwp  
// output.writeLong(nPos); >uN`q1?l'  
output.writeLong(fileSplitterFetch.nStartPos); &"dT/5}6  
output.writeLong(fileSplitterFetch.nEndPos); KKm0@Y   
} CroI,=a&,  
output.close(); W)"PYC4  
} ^(ks^<}  
catch(IOException e){e.printStackTrace ();} VjU;[  
catch(Exception e){e.printStackTrace ();} =RR225  
} @l9qH1  
J@ x%TA  
_C9*M6IU  
//读取保存的下载信息(文件指针位置) KlgPDV9mg  
private void read_nPos() e&dE>m  
{ QN[-XQ>Xt  
try{ )hH9VGZq(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); GyV3]Qqj  
int nCount = input.readInt(); !F0MLvdX7^  
nStartPos = new long[nCount]; g-=)RIwm  
nEndPos = new long[nCount]; tt=?*n  
for(int i=0;i<nStartPos.length;i++) H'myd=*h~8  
{ ?iH`-SY  
nStartPos = input.readLong(); Ti/t\'6  
nEndPos = input.readLong(); r3o_mO?X  
} L&1VPli  
input.close(); ; Xy\7tx  
} uLYz!E+E  
catch(IOException e){e.printStackTrace ();} e{edI{g  
catch(Exception e){e.printStackTrace ();} !1f8~"Z  
} z`-?5-a]I  
LOyL:~$  
xq:.|{HUk  
private void processErrorCode(int nErrorCode) x^aqnKoJ%\  
{ uX{n#i,~L  
System.err.println("Error Code : " + nErrorCode); N> R abD  
} MnvFmYgxA  
ag^L' h$  
!j8h$+:K  
//停止文件下载 37 )Dx  
public void siteStop() qkC+9Sk  
{ w]n20&  
bStop = true; :.!]+#Me  
for(int i=0;i<nStartPos.length;i++) 96aA2s1  
fileSplitterFetch.splitterStop(); :>to?~Z1  
dzZ74FE!t  
BM*9d%m^  
} i<|5~tm  
} @psyO]D=j%  
//负责部分文件的抓取 }7CMXw [  
**FileSplitterFetch.java .op: 2y9]  
*/ 0bxB@(NO  
package NetFox; 3X$)cZQ  
Y:C7S~  
OKfJ  
import java.io.*; 8~?3: IZ  
import java.net.*; !oeu  
4 vwa/?  
>{i/LC^S  
public class FileSplitterFetch extends Thread { xwa5dtcng  
$x5P5^Y  
n(.y_NEgV!  
String sURL; //File URL ]gYnw;W$  
long nStartPos; //File Snippet Start Position 2Yt#%bj7^  
long nEndPos; //File Snippet End Position U@+ @Mc  
int nThreadID; //Thread's ID uR{HCZ-  
boolean bDownOver = false; //Downing is over u2 a U0k:  
boolean bStop = false; //Stop identical FR9<$  
FileAccessI fileAccessI = null; //File Access interface X l#P@60  
m xtLcG4G  
Z%~j)  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException LRBcW;.Su  
{ }}XYV eI  
this.sURL = sURL; edhNQWn  
this.nStartPos = nStart; *,hS-  
this.nEndPos = nEnd;  t4pc2b  
nThreadID = id; t3K7W2bz  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D.o|pTZ  
} }fnp}L  
kf+]bV  
MZf$8R  
public void run() XnrOC|P$  
{ D/jB .  
while(nStartPos < nEndPos && !bStop) G?!b00H  
{ `HvU_ja;  
9ctvy?53H  
fk4s19;?  
try{ IbC(/i#%`  
URL url = new URL(sURL); egboLqn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IlsXj`!e  
httpConnection.setRequestProperty("User-Agent","NetFox"); O{a<f7 W  
String sProperty = "bytes="+nStartPos+"-"; pfgFHNH:  
httpConnection.setRequestProperty("RANGE",sProperty); n'=-bj`  
Utility.log(sProperty); ,wE]:|`qJ  
8<M'~G%CEq  
mh]'/C_*<w  
InputStream input = httpConnection.getInputStream(); ?-0k3  
//logResponseHead(httpConnection); %)T>Wn%b]v  
;4tVFqR  
+[*VU2f t  
byte[] b = new byte[1024]; }\}pSqW  
int nRead; `E>HpRcxD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L<!}!v5ja  
{ :#58m0YLA:  
nStartPos += fileAccessI.write(b,0,nRead); V{;!vt~  
//if(nThreadID == 1) Xu`c_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F+Rtoq|  
} 8*3o 9$Pj  
pDb5t>  
'gk.J  
Utility.log("Thread " + nThreadID + " is over!"); \bqIe}3V7  
bDownOver = true; PHl{pE*  
//nPos = fileAccessI.write (b,0,nRead); %"PG/avo  
} s42M[BW]  
catch(Exception e){e.printStackTrace ();} .GUm3b  
} >k,|N4(  
} J]/TxUE  
%`%oupqm+  
!"/]<OQ   
//打印回应的头信息 =3OK 3|  
public void logResponseHead(HttpURLConnection con) $Z6g/bD`E  
{ mZ 39 s  
for(int i=1;;i++) %eWzr  
{ !!Z#'Wq  
String header=con.getHeaderFieldKey(i); 4s nL((  
if(header!=null) =LV7K8FSd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); tAFKq>\  
Utility.log(header+" : "+con.getHeaderField(header)); 3Yf&F([t  
else w2!G"oD  
break; n4Nb,)M  
} SLp &_S@4  
} P'f =r%  
m7wD#?lm  
CY#|VE M  
public void splitterStop() /ylO["<Q  
{ 1ael{b!  
bStop = true; rF:C({y  
} }&D~P>1  
h\\fb[``  
qd#?8  
} qp_lMz  
.gTla  
Hs/ aU_  
/* lo*OmAF  
**FileAccess.java \7PPFKS  
*//文件访问(定位,写) Q\Dx/?g!vx  
package NetFox; r!SMF ]?SJ  
import java.io.*; ^Gt&c_gH  
u~n*P``{  
)9F-h8 &"  
public class FileAccessI implements Serializable{ f =@'F=  
Ix@rn  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >QO^h<.>  
RandomAccessFile oSavedFile; g^|}e?  
long nPos; X{4jyi-<  
T<(1)N1H`  
#\s*>Z  
public FileAccessI() throws IOException .[&0FHnJ5  
{ ap=m5h27  
this("",0); ~_opU(;f  
} aX`"V/  
+v.uP [H  
{<&i4;  
public FileAccessI(String sName,long nPos) throws IOException @_s`@ ,=  
{ Ie{98  
oSavedFile = new RandomAccessFile(sName,"rw"); Cbu/7z   
this.nPos = nPos; ]&6# {I-  
oSavedFile.seek(nPos); HS>(y2}'  
} !/] F.0  
8* 7t1$  
.4on7<-a  
public synchronized int write(byte[] b,int nStart,int nLen) & $E[l'  
{ uQh dg4  
int n = -1; X[/>{rK  
try{ ]v^/c~"${  
oSavedFile.write(b,nStart,nLen); fy+fJ )4sj  
n = nLen; mdjPK rF<  
} &*2\1;1tB  
catch(IOException e) {gh41G;n  
{ 2gM=vaiH=  
e.printStackTrace (); kFKc9}7W  
} Mo?eVtZ  
s~e<Pr?yu  
|dIP &9  
return n; Qn= 3b:S-  
} e_'/4 n  
AGaM &x=  
BS3Aczwk  
} ,=sbK?&  
Ku;|Dz/=o  
\f| Hk*@  
/* DV+M;rs  
**SiteInfoBean.java 9R_2>BDn  
*/ 9/A$ 3#wF  
package NetFox; _)|_KQQu  
F6>K FU8  
:5)Dn87  
public class SiteInfoBean { vHR-mQUs  
TdGda'C  
>tF3|:\  
private String sSiteURL; //Site's URL 'Cv,:Q  
private String sFilePath; //Saved File's Path ]0N'Wtbn  
private String sFileName; //Saved File's Name TljN!nv]  
private int nSplitter; //Count of Splited Downloading File *u LOoq  
k(hYNmmo j  
d4ANh+}X"_  
public SiteInfoBean() ,TeJx+z^  
{//nSplitter的缺省值为5 )Ve-)rZ  
//default value of nSplitter is 5 #,dNhUV#  
this("","","",5); ?%RAX CK  
} G!]%xFwYa  
,RmXZnWY  
h>ZNPP8N  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Oi#4|*b{W  
{ 5)712b(&  
sSiteURL= sURL; rP4v_?Zg+  
sFilePath = sPath; vW6 a=j8  
sFileName = sName; Xge]3Ub  
this.nSplitter = nSpiltter; =BD}+(3  
%=p:\+`VI  
^gw htnI  
} [6 d~q]KH  
^RL#(O  
nc<w DE6  
public String getSSiteURL() 5x$/.U  
{ ~ZrSoVP=  
return sSiteURL; LV4\zd6  
} /#mq*kNIM6  
.II*wK k  
{ 'A`ram  
public void setSSiteURL(String value) x"g-okLN  
{ BdW Rm=  
sSiteURL = value; sk'< K5~  
} vjo@aY.x  
WP(+jL^-  
'Cki"4%<  
public String getSFilePath() zzlqj){F  
{ JFOto,6L:  
return sFilePath; :TU|;(p  
} ku2g FO  
s |40v@ M  
|W't-}yf  
public void setSFilePath(String value) '5^$v{  
{ g/*x;d=  
sFilePath = value; m(2(Caz{  
} NO$n-<ag  
PK&3nXF%4  
C\-Abq c  
public String getSFileName() By3y.}'Ub9  
{ X?6E0/r&9  
return sFileName; N=2BrKb)o  
} rw CFt6;v  
rbC4/9G\  
!T+jb\O_  
public void setSFileName(String value) '(ZJsw  
{ ]V*ku%L0  
sFileName = value; 6snDv4  
} 4}i2j  
SW94(4qo  
LwPZRE#  
public int getNSplitter() fj 14'T  
{ s,5SWdb\v  
return nSplitter; VV_Zrje  
} rTJ='<hIy  
wEQ7=Gyx  
M<Gr~RKmAn  
public void setNSplitter(int nCount) J A=9EnTU  
{ C-wwQbdG/  
nSplitter = nCount; l7{]jKJue  
} f82$_1s^  
}  {J aulg  
/5x~3~  
}kNbqwVP  
/* It5U=PU  
**Utility.java M lv  
*/ KOQiX?'  
package NetFox; }"$2F0  
A~2U9f+\  
t>f61<27eB  
public class Utility { FWi c/7  
[ H~Yg2O  
g Kp5*  
public Utility() S%NS7$`a  
{ jruXl>T!U  
E$u9Jbe  
';'TCb{f*  
} K;n2mXYGM  
D]n"`< Ho  
//线程睡眠 _oV;Y`_  
public static void sleep(int nSecond) z XI [f  
{ >"OwdAvX  
try{ i146@<\G{P  
Thread.sleep(nSecond); L9lNAiOH  
} |*G$ilu  
catch(Exception e) \t pJ   
{ X2RM*y|  
e.printStackTrace (); /0S2Om h  
} k`j>lhH  
} J 8!D."'Q0  
zRO-oOJ  
//日志 \(4"kY_=  
public static void log(String sMsg) Dw%V.J/&o  
{ 2 }9of[  
System.err.println(sMsg); Z.4 vKO[<  
} a&sVcsX  
"w PA;4VQ  
@ij8AGE:  
public static void log(int sMsg) /.knZ_aJ!  
{ 6%j v|\>  
System.err.println(sMsg); JYAtQTOR  
} `6R.*hq  
} ;)6LX-  
T(GEFnt Y  
%=ZN2)7{  
/* b]-~{' +  
**TestMethod.java 5s5GBJ?  
*/ 5l(8{,NDt  
package NetFox; X0QY:?  
}3b3^f  
b I%Sq+"}  
public class TestMethod { pBZf=!+E  
G{ |0}  
*A^j>lV  
public TestMethod() ^| b]E  
{ ///xx/weblogic60b2_win.exe UQ7E7yY#  
try{ z: ;ZPSn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &Zzd6[G+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +vDEDOS1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +#B4Z'nT  
fileFetch.start(); 1X ?9Ji)h  
} m'!smS x8  
catch(Exception e){e.printStackTrace ();} *mvDh9v  
;0Vyim)S]  
rXIFCt8J  
} k=nN#SMn  
*y}<7R  
$] gwaJ:  
public static void main(String[] args) p)x*uqSd  
{ H'2J!/V  
new TestMethod(); ,qj1"e  
} n#US4&uT4A  
} 3 L:s5  
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