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http断点续传简单实现(java)

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/* OP |{R7uC  
**SiteFileFetch.java @dX0gHU[c  
*/ J9ovy>G  
package NetFox; Wd$N[|  
import java.io.*; Cvm ZW$5Yo  
import java.net.*; D}"\nCz}y&  
j)Kk:BFFY  
a1ZGMQq!  
public class SiteFileFetch extends Thread { p`gg   
OH5 kT$  
j^KM   
SiteInfoBean siteInfoBean = null; //文件信息Bean deaxb8'7  
long[] nStartPos; //开始位置 ~B>I?j  
long[] nEndPos; //结束位置 %r6LU<;1@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q9pBS1Ej  
long nFileLength; //文件长度 #[sC H  
boolean bFirst = true; //是否第一次取文件 pTUsdao^,  
boolean bStop = false; //停止标志 1mOZ\L!m*  
File tmpFile; //文件下载的临时信息 ']$ttfJB  
DataOutputStream output; //输出到文件的输出流 <9-tA\`8N  
3Zsqx =w  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) m#, F%s  
public SiteFileFetch(SiteInfoBean bean) throws IOException _jH1Mcq  
{ g-mK(kY4p  
siteInfoBean = bean; }^G'oR1LF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); C JiMg'K  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @SPmb o  
if(tmpFile.exists ()) <<(~'$~,L  
{ }llzO  
bFirst = false; pX6T7  
read_nPos(); d(, -13  
} ^]'p927  
else *-Lnsi^7v  
{ ,qiS;2(  
nStartPos = new long[bean.getNSplitter()]; 9L%&4V}BIS  
nEndPos = new long[bean.getNSplitter()]; 9^0 'VRG  
} @l"GfDf L9  
_kH#{4`Hw  
la)f\Nk  
)[9L|o5D  
} w|Zq5|[  
aEXV^5;,pJ  
\#tr4g~u  
public void run() qfC9 {gu  
{ 0J$wX yh  
//获得文件长度 4}580mBc  
//分割文件 f: 7Y  
//实例FileSplitterFetch ++,mM7a  
//启动FileSplitterFetch线程 -2> L*"^  
//等待子线程返回 Uo^s]H#:  
try{ kKE 2~ q  
if(bFirst) j])iyn~-Ke  
{ !SJmu}OB]  
nFileLength = getFileSize(); cJ]`/YJ  
if(nFileLength == -1)  t8GJ;  
{ HLYM(Pz  
System.err.println("File Length is not known!"); =Z#tZ{"  
} A6iyJFm D  
else if(nFileLength == -2) i=o>Bl@f  
{ HxZ4t  
System.err.println("File is not access!"); <py~(q  
} 2yq.<Wz<  
else ui9gt"qS`  
{ +6gS]  
for(int i=0;i<nStartPos.length;i++) b@1QE  
{ 7azxqa5:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2#/ KS^  
} ]Wd{4(b  
for(int i=0;i<nEndPos.length-1;i++) 42z9N\ f  
{ ?N11R?8  
nEndPos = nStartPos[i+1]; 7MGc+M(p  
} BC@"WlD  
nEndPos[nEndPos.length-1] = nFileLength; Crpk q/M  
} ::TUSz2/2  
} bL0+v@(r  
DMf^>{[  
i":-g"d  
//启动子线程 NPB':r-8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; NLz$jk%=g  
for(int i=0;i<nStartPos.length;i++) Qs% f6rL  
{ B|,6m 3.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KL5rF,DME  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~PlwPvWo  
nStartPos,nEndPos,i); OPKX&)SE-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [&{"1Z  
fileSplitterFetch.start(); 9s*Lzi[}  
} E\V>3rse  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ni%^w(J3Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;"Ot\:0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *D<sk7  
nEndPos = " + nFileLength); }FM<uBKW  
// fileSplitterFetch[nPos.length-1].start(); <mm}IdH  
~Dy0HVE   
w-\fCp )  
//等待子线程结束 nosEo? {  
//int count = 0; m};_\Db`  
//是否结束while循环 -w@fd]g  
boolean breakWhile = false; PA5g]Tz  
`J-"S<c?_  
' > \*  
while(!bStop) p{-1%jQ}]  
{ A<TJ3Jp]  
write_nPos(); ![vc/wuf  
Utility.sleep(500); 1H[lf B  
breakWhile = true; |23 }~c,  
<K97eAcW  
p:4vjh=1h  
for(int i=0;i<nStartPos.length;i++) eM9~&{m.  
{ jG.*tuf  
if(!fileSplitterFetch.bDownOver) RM i 2Ip  
{ LXXxwIBS  
breakWhile = false; p19Zxh  
break; uWfse19  
} U| N`X54  
} 6B+ @76wH  
if(breakWhile) a:;*"p[R  
break; Y7{|EI+@  
vfy- ;R(  
oO UVU}H  
//count++; rg'? ?rq  
//if(count>4) Pc(2'r@#  
// siteStop(); 3BSeZ:j7  
} s-C.+9  
M?\)&2f[Z  
F~DG:x~  
System.err.println("文件下载结束!"); Ffhbs D  
} u j:w^t ][  
catch(Exception e){e.printStackTrace ();} Y]Fq)  -  
} "RShsJZMH  
{(tE pr  
#Se  
//获得文件长度 )0GnTB;5Z  
public long getFileSize() q7)$WXe2LM  
{ 6Nl$&jL  
int nFileLength = -1; l y%**iN  
try{ w"BTu-I  
URL url = new URL(siteInfoBean.getSSiteURL()); %(kq Hxc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RB\WttI  
httpConnection.setRequestProperty("User-Agent","NetFox"); E"" /dC:B  
HOUyB's'  
! \gRXP}  
int responseCode=httpConnection.getResponseCode(); oqY?#p/  
if(responseCode>=400) Xoik%T-  
{ b%_QL3 m6  
processErrorCode(responseCode); +(/Z=4;,[  
return -2; //-2 represent access is error 1a)_Lko  
} ad~ qr n\  
GqAedz;.  
F9c2JBOM  
String sHeader; xH f9N?  
sEj:%`l|  
T,IV)aq  
for(int i=1;;i++) wM yPR_  
{ #k"[TCQ>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ( ou:"Y  
//Utility.log(in.readLine()); sXydMk`J  
sHeader=httpConnection.getHeaderFieldKey(i); Bdg*XfXXk  
if(sHeader!=null) M84LbgGM%  
{ a-} %R  
if(sHeader.equals("Content-Length")) 54;iLL  
{ Sx~_p3_5U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RXof$2CZS  
break; '~f@p~P  
} cp2fDn  
} HdLkof2i  
else wYxizNv,  
break; ef. lM]cO  
} .kYzB.3@]  
} ?ykZY0{B  
catch(IOException e){e.printStackTrace ();} ,-1$Vh@wM  
catch(Exception e){e.printStackTrace ();} GS$k  
FvNO*'xP  
i&3 0n#  
Utility.log(nFileLength); C>u 3n^  
>4VU  
!'gz&3B~h  
return nFileLength; bOFLI#p&  
} 0 iE).Za0g  
;`+RSr^8$  
sogbD9Jc  
//保存下载信息(文件指针位置) M$?6 '  
private void write_nPos() 5ya3mN E  
{ nn   
try{ x2B"%3th0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); C&st7. (k  
output.writeInt(nStartPos.length); -#o+x Jj  
for(int i=0;i<nStartPos.length;i++) $oQsh|sTI  
{ 6P~"7k  
// output.writeLong(nPos); (g)@wNBW  
output.writeLong(fileSplitterFetch.nStartPos); &59#$LyH`%  
output.writeLong(fileSplitterFetch.nEndPos); 6^aYW#O<Ua  
} b mm@oi  
output.close(); 6m" 75  
} 1h#k&r#*3  
catch(IOException e){e.printStackTrace ();} qN0#=X  
catch(Exception e){e.printStackTrace ();} M+E5PZ|_  
} I>3]4mI*a  
4GfLS.Ip  
ygW@[^g  
//读取保存的下载信息(文件指针位置) 'f}S ,i +q  
private void read_nPos() ]p*) PpIl  
{ vedMzef[@>  
try{ _Ry.Wth  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _%2Umy|  
int nCount = input.readInt(); pzax~Vp  
nStartPos = new long[nCount]; <D dHP  
nEndPos = new long[nCount]; 0V#t ;`Q3  
for(int i=0;i<nStartPos.length;i++) 7, 13g)  
{ 9HE(*S  
nStartPos = input.readLong(); g"&bX4uD)  
nEndPos = input.readLong(); ?|7+cz$g  
} D{4hNO  
input.close(); (rG1_lUDu  
} {^kG<v.vV  
catch(IOException e){e.printStackTrace ();} GA_`C"mx  
catch(Exception e){e.printStackTrace ();} ?iLd5 Z  
} ,?`1ve_K<  
IeB6r+4|  
NslA/"*  
private void processErrorCode(int nErrorCode) H|)1T-%  
{ :ky<`Jfr`  
System.err.println("Error Code : " + nErrorCode); 9$,gTU_a  
} Tb= {g;0 @  
M96( Rg  
V0 F30rK  
//停止文件下载 zn ?;>Bl  
public void siteStop() c9 uT`h  
{ !~N4}!X3du  
bStop = true; w~U`+2a3  
for(int i=0;i<nStartPos.length;i++) rc$!$~|I3Z  
fileSplitterFetch.splitterStop(); mVK9NK  
v|I5Gz$qpa  
k4$q|x7+%  
} KY`96~z  
} <VU4rk^=  
//负责部分文件的抓取 y,&M\3A  
**FileSplitterFetch.java hcgc =$^  
*/ o1WidJ"  
package NetFox; qZJ*J+  
ow_y  
kN j3!u$  
import java.io.*; V"H 7zx  
import java.net.*; NoO+xLHw8  
unnx#e]  
V*zz- 2 _i  
public class FileSplitterFetch extends Thread { klJ[ {p  
F!&pENQ  
~{vdP=/WP  
String sURL; //File URL MgQU6O<  
long nStartPos; //File Snippet Start Position "-n%874IT  
long nEndPos; //File Snippet End Position +q j*P9  
int nThreadID; //Thread's ID /HuYduGdP  
boolean bDownOver = false; //Downing is over ZGpTw[5ql  
boolean bStop = false; //Stop identical @pG lWw9*  
FileAccessI fileAccessI = null; //File Access interface uT}TSwgp  
b3b~T]]  
8q [c  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException kr(<Y|  
{ %W4aKb?BT  
this.sURL = sURL; 2-V)>98  
this.nStartPos = nStart; 8RAeJ~e  
this.nEndPos = nEnd; 8M|)ojH  
nThreadID = id; 2ly,l[p8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *fl{Y(_OO  
} 6#)Jl  
T_x+sv=|X!  
WYC1rfd=  
public void run() As+;qNO  
{ 'K3 s4x($  
while(nStartPos < nEndPos && !bStop) vzcBo%  
{ uR ;-eK  
l-S'ATZ0p  
T5azYdzJy  
try{ F[kW:-ne@Z  
URL url = new URL(sURL); zZ9<4"CIk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9*|3E"Vr  
httpConnection.setRequestProperty("User-Agent","NetFox"); *?bk?*?s  
String sProperty = "bytes="+nStartPos+"-"; =kb6xmB^t  
httpConnection.setRequestProperty("RANGE",sProperty); #t@x6Vt  
Utility.log(sProperty); d{yIy'+0/  
pf8O`e,Awf  
$}nh[@  
InputStream input = httpConnection.getInputStream(); '^U tbp2<  
//logResponseHead(httpConnection); R6Zj=l[  
8b(1ut{  
!(*a+ur&i  
byte[] b = new byte[1024]; 'q92E(  
int nRead; IE)"rTI)b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *NW QmC~  
{ ;4G\]%c)E{  
nStartPos += fileAccessI.write(b,0,nRead); t @(9ga(  
//if(nThreadID == 1) /> 3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); KR=d"t Qw  
} 2]D$|M?$~  
/c@*eU  
>7nV$.5S  
Utility.log("Thread " + nThreadID + " is over!"); V3mjb H>F  
bDownOver = true; *IWFeu7y  
//nPos = fileAccessI.write (b,0,nRead); r]8x;v1  
} VyWYfPK  
catch(Exception e){e.printStackTrace ();} ov`^o25f  
} H^D 3NuUC  
} X 45x~8f  
ypD<2z^  
z!s. 9  
//打印回应的头信息 +9zJlL^A%  
public void logResponseHead(HttpURLConnection con) VW9>xVd4  
{ UZje>. ~?  
for(int i=1;;i++) {}_Nep/;  
{ oWp}O?  
String header=con.getHeaderFieldKey(i); ZU|6jI}  
if(header!=null) dP$8JI{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _ }E-~I>  
Utility.log(header+" : "+con.getHeaderField(header)); %j'G.*TD  
else #2Pr Gz]  
break; *N-;V|{  
} U~:N^Sc  
} =.36y9Mfo  
_F`$ d2  
[ WV@w  
public void splitterStop() Y=vVxVI\  
{ B;Xoa,  
bStop = true; 7fju  
} t7w-TJvP  
~u /aOd  
&8<<!#ob  
} 0R HS]cN  
+yf(Rs)!  
GilQtd3\  
/* YV/>8*i  
**FileAccess.java v7i^O`{eD?  
*//文件访问(定位,写) d,c8Hs8  
package NetFox; J~Cc9"(  
import java.io.*; E/mubA(&  
Ap5}5 ewM  
3CR@' qG-  
public class FileAccessI implements Serializable{ ;,1=zhKU.  
4_PCq Ep)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pOC% oj  
RandomAccessFile oSavedFile; \  Md 3  
long nPos; Fe!D%p Qv  
^WE4*.(  
YD&|1h  
public FileAccessI() throws IOException F9(._ow[  
{ T@TIz z  
this("",0); _om0 e=5)  
} AV40:y\RW  
&v^!y=Bt  
bIgh@= 2  
public FileAccessI(String sName,long nPos) throws IOException P$Z}  
{ '_:(oAi,C  
oSavedFile = new RandomAccessFile(sName,"rw"); B*\$ /bk,  
this.nPos = nPos; !FTNmyM~F  
oSavedFile.seek(nPos); w8O" =},  
} g;pR^D'M5C  
jY7=mAd  
+R-h ,$\=7  
public synchronized int write(byte[] b,int nStart,int nLen) wfgqgPo!v  
{ Ntb:en!X  
int n = -1; pb!V|#u"  
try{ aaDP9FW9e  
oSavedFile.write(b,nStart,nLen); )Im3'0l>  
n = nLen; Sw~(uH_l  
} ^ eQFg>  
catch(IOException e) |% z ^N*  
{ f-;$0mTQ  
e.printStackTrace (); 0n Y6A~  
} {esJ=FV\  
U{6oLqwq3Y  
_V@WNo%B  
return n; HBH$  
} i AdGgK  
X) V7bVW  
[4sEVu}  
} 9Ycn0  
xJ{_qP  
vY6oV jM  
/* XZ`:wmc|  
**SiteInfoBean.java ,LD m8   
*/ #05jC6  
package NetFox; lVz9k  
vw2`:]Q+  
{_?rh,9q  
public class SiteInfoBean { S,)d(g3>  
k1)%.pt%  
7BR8/4gcPu  
private String sSiteURL; //Site's URL cHx%Nd\  
private String sFilePath; //Saved File's Path JK]R*!{n  
private String sFileName; //Saved File's Name h.)h@$d  
private int nSplitter; //Count of Splited Downloading File dBSbu=^$)  
 v,=v  
+ WVIZZ8  
public SiteInfoBean() _A98  
{//nSplitter的缺省值为5 !Uh2}ic  
//default value of nSplitter is 5 <a4 TO8  
this("","","",5); As~(7?]r  
} w~z[wmOkp  
#2RiLht  
/kgeV4]zR  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G O{ . 9_2  
{ *wuqa) q2  
sSiteURL= sURL; !*aPEf270  
sFilePath = sPath; u:&o}[  
sFileName = sName; ~e `Bq>  
this.nSplitter = nSpiltter; Kz jC/1sd  
]PWDE"  
{ox2Tg?  
} sV/l5]b]  
O:'?n8rWL  
+vW)vS[  
public String getSSiteURL() :w`3cw Q  
{ Kv37s0|g  
return sSiteURL; g:7,~}_}^  
} j~E",7Q'  
20b<68h$:  
Fk "Ee&H)(  
public void setSSiteURL(String value) ~ Vw9  
{ RBwO+J53y  
sSiteURL = value; ]}Z4P-"t  
} Ej=3/RBsV  
Tlq-m2]  
'm3t|:nMU  
public String getSFilePath() !ErH~<f%K  
{ 6KHN&P  
return sFilePath; R\mR$\cS  
}  x}TS  
p8}(kHUp(  
POAw M  
public void setSFilePath(String value) H#i{?RM@l  
{ ! }f1`/   
sFilePath = value; g13 rx%-  
} mO*^1  
#>[a{<;Kn  
q5x[~]?  
public String getSFileName() 5O <>mCF  
{ uR;gVO+QC  
return sFileName; #m<tJnEO  
} )yG"^Ulu  
&<y2q/U}  
fX~'Zk\u  
public void setSFileName(String value) aAE>)#f(  
{ :#5xA?=* S  
sFileName = value; 6E ~g#(8  
} 2S"Nf8>zp  
D&G"BZx|  
2)X4y"l  
public int getNSplitter() \Q~8?p+  
{  Ea6 &~"  
return nSplitter; tZyo`[La  
} 0'5/K ,  
Rk6deI]  
({s6eqMhDd  
public void setNSplitter(int nCount) S4UM|`  
{ t5B7I59  
nSplitter = nCount; 1'.7_EQ4T  
} z~*g~RKS!  
} @"-</x3o  
e~l#4{w  
;U9J++\d<A  
/* 5xCT~y/a  
**Utility.java 8:=n*  
*/ B* kcN lW  
package NetFox; P{OAV+cG  
T9W`?A  
rxn Frx  
public class Utility { fKH7xu!V4+  
\Ig68dFf%  
K5Q43 e1  
public Utility() 3`E=#ff%  
{ pM;vH]|  
&H}r%%|A  
gTl<wo +  
} az0<5 Bq)  
}jH7iyjD  
//线程睡眠 o?L'Pg  
public static void sleep(int nSecond) YB<*"HxM)}  
{ ;Uc0o!1  
try{ qgIb/6;xQ  
Thread.sleep(nSecond); >Y7a4~ufko  
} `Z: R Ce^  
catch(Exception e) N6K* d` o  
{ [x=jH>Y  
e.printStackTrace (); 7SDFz}  
} PyVC}dUAX  
} %^sTU4D5  
1"Z@Q`}  
//日志 4iA Z+l5&  
public static void log(String sMsg) 'c2W}$q  
{ De7T s  
System.err.println(sMsg); =4V&*go*\  
} *B`Zq)  
gE#>RM5D  
j',W 64  
public static void log(int sMsg) glDcUCF3  
{ v+p {|X-  
System.err.println(sMsg); 0a8/B>  
} {3;AwhN0H  
} &'cL%.  
vEf4HZ&w  
hfpJ+[  
/* XL#[ %X9  
**TestMethod.java {{V8;y  
*/ #^m0aB7r  
package NetFox; =q N2Xg/  
rpeJkG@+  
SJD@&m%?[  
public class TestMethod { 9T#;,{VQ  
P96pm6H_;  
+]=e;LN$0  
public TestMethod() EY*(Bw  
{ ///xx/weblogic60b2_win.exe fYKOJ5f  
try{ C{TA.\   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); oFOnjK"|F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %ZHP2j %~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oFjIA!  
fileFetch.start(); ;&H4u)  
} >WY#4  
catch(Exception e){e.printStackTrace ();} DN4$Jva  
r0p w_j  
YK|bXSA[  
} [MuEoWrq(}  
),%6V5a+E  
wFG3KzEq ~  
public static void main(String[] args) 8XbA'% o  
{ @lJzr3}WZ  
new TestMethod(); {vAE:W.s  
} $w"$r$K9K  
} /cc\fw1+  
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