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http断点续传简单实现(java)

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/* .G"UM>.}d  
**SiteFileFetch.java "I"(yiKD  
*/ 35}{dr  
package NetFox; Y7QIFY's~  
import java.io.*; O>Y Xvu  
import java.net.*; dgb#PxOMH  
Ho3$T  
'Xl[ y  
public class SiteFileFetch extends Thread { ,L iX  
de.!~%D  
%kM|Hk3d  
SiteInfoBean siteInfoBean = null; //文件信息Bean [i7Ug.Oi"  
long[] nStartPos; //开始位置 L B:wo .X  
long[] nEndPos; //结束位置 J&%d(EJM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 U%2[,c_  
long nFileLength; //文件长度 _wa1R+`_  
boolean bFirst = true; //是否第一次取文件 H{Zfbb  
boolean bStop = false; //停止标志 ES~ykE  
File tmpFile; //文件下载的临时信息 %i!&Fr  
DataOutputStream output; //输出到文件的输出流 &&Sl0(6x[T  
{VWX?Mm  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) #b[B$  
public SiteFileFetch(SiteInfoBean bean) throws IOException EZ+_*_9  
{ GEr]zMYG[A  
siteInfoBean = bean; 'g<0MOq{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); seT?:PCA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `^t0379e  
if(tmpFile.exists ()) 3*13XQ  
{ }R.<\  
bFirst = false; RS'%;B-)  
read_nPos(); sq6|J])GgU  
} "xS?#^a  
else `(j}2X'[  
{ Hu"?wZj  
nStartPos = new long[bean.getNSplitter()]; X@$x(Zc  
nEndPos = new long[bean.getNSplitter()]; %]/O0#E3Kz  
} &yFt@g]  
AL #w  
DL&\iR  
F1skI _!  
} &5Ai&<q"p  
0QE2e'}}-  
K1S)S8.EZ8  
public void run() E 9=a+l9  
{ ZqaCe>  
//获得文件长度 ;x.xj/7  
//分割文件 ?:bW@x  
//实例FileSplitterFetch F\1{bN|3  
//启动FileSplitterFetch线程 9Ra_[1  
//等待子线程返回 y99 3uP   
try{ 16q"A$  
if(bFirst) ]=5nC)|  
{ Do3;-yp>`  
nFileLength = getFileSize(); -\mbrbG9H  
if(nFileLength == -1) wIi_d6?  
{ 2=pVX  
System.err.println("File Length is not known!"); ,(0q  
} cC'{+j8-a  
else if(nFileLength == -2) VH3 j  
{ `@MY}/ o.  
System.err.println("File is not access!"); \M4/?<g  
} psb$rbu7[  
else s_} 1J,Y  
{ K * Tj;  
for(int i=0;i<nStartPos.length;i++) gie}k)&M  
{ X9^a:7(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); W(N@`^  
} O9>& E;`5  
for(int i=0;i<nEndPos.length-1;i++) (;^VdiJ  
{ 1n7tmRl  
nEndPos = nStartPos[i+1]; q5il9*)d (  
} x%kS:!  
nEndPos[nEndPos.length-1] = nFileLength; T7eo_Mn  
} B|#*I[4`w@  
} Hd(|fc{2  
K-V NU  
MH{$"^K  
//启动子线程 #`P4s>IL1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; V9 <!pMj  
for(int i=0;i<nStartPos.length;i++) %zg&eFRHI  
{ %;0Llxf"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /JPyADi  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wTBp=)1)f  
nStartPos,nEndPos,i); q7-Eu4w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); uQ4WM  
fileSplitterFetch.start(); \D8d!gr  
} K9Dxb  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {3Z&C$:s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y$8 >fv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3RpDIl`0  
nEndPos = " + nFileLength); ~Ein)5  
// fileSplitterFetch[nPos.length-1].start(); lxTW1kr  
Z IfhC'  
;5tSXgGw7  
//等待子线程结束 D@T>z;  
//int count = 0; AtNu:U$  
//是否结束while循环 oWGtKtDhH  
boolean breakWhile = false; J[fjl 6p  
Cg NfqT0  
B42.;4"T  
while(!bStop) %h;~@-$  
{ Bfw]#"N`  
write_nPos(); M|e Qds  
Utility.sleep(500); *RKYdwnb  
breakWhile = true; (I~-mzu\  
{4"!~W  
)cc:Z7p  
for(int i=0;i<nStartPos.length;i++) :4|W;Lkd!  
{ wkm;yCF+  
if(!fileSplitterFetch.bDownOver) 7B GMG|  
{ @$ E&H`da  
breakWhile = false; <F!On5=W*  
break; qG.HJD  
} <TmMUA)`}  
} &mj98  
if(breakWhile) {<7!=@j  
break; ?[Xv(60]  
j["b*X`8G  
d[ql7  
//count++; )24r^21.q  
//if(count>4) `mV&[`NZ  
// siteStop(); i,>yIPBU!  
} (C/2shr 8  
|<&9_Aq_  
[>xwwm  
System.err.println("文件下载结束!"); w4Nm4To  
} [h7nOUL!  
catch(Exception e){e.printStackTrace ();} C Sx V^  
} U1<EAGo|  
]v7f9MC'\  
+ZeHZjd  
//获得文件长度 'Dyt"wfo  
public long getFileSize() `(A>7;]:  
{ } y@pAeS,  
int nFileLength = -1; omQa N#!,  
try{ r(./00a  
URL url = new URL(siteInfoBean.getSSiteURL()); h32QEz-+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ikf6Y$nWfF  
httpConnection.setRequestProperty("User-Agent","NetFox"); R%iyNK,  
l@ vaupg  
3# G;uWN-  
int responseCode=httpConnection.getResponseCode(); 4R-Y9:^t  
if(responseCode>=400) ur^)bp<n  
{ 8/X#thG  
processErrorCode(responseCode); w=>~pYASH  
return -2; //-2 represent access is error 4PUSFZK?  
} fMRBGcg7Dc  
7!Z\B-_,  
-MZ LkSU  
String sHeader; 6tXx--Nh  
,w%cX{  
%(h-cuhq  
for(int i=1;;i++) Fi.gf?d  
{ -miWXEe@l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); CHp`4  
//Utility.log(in.readLine()); YnC7e2  
sHeader=httpConnection.getHeaderFieldKey(i); :X-Z|Pv8  
if(sHeader!=null) Fl\X&6k  
{ +grIw# j  
if(sHeader.equals("Content-Length")) FHWzwi*u}  
{ BG!;9Z{u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7r,'a{Rcn  
break; vKYdYa\  
} z6e)|*cA$  
} ]O2ku^yM  
else )3g7dtq}  
break; v2R41*z,  
} txM R[o_  
} 1'tagv?  
catch(IOException e){e.printStackTrace ();} '3S S%W  
catch(Exception e){e.printStackTrace ();} VF1)dd  
+#~=QT9  
^mr#t #[e  
Utility.log(nFileLength); F;p>bw  
0MDdcjqw  
K r $R"  
return nFileLength; Rh#0EbE2  
} AA&398F  
7Yp;B:5@  
ro{q':Z3  
//保存下载信息(文件指针位置) ]nE_(*w  
private void write_nPos() ;4<CnC**  
{ nHxos` Qx  
try{ 3In` !@EJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ek\f x*Lz  
output.writeInt(nStartPos.length); uJVu:E.#1  
for(int i=0;i<nStartPos.length;i++) EacqQFErl  
{ i-oi?x<u&(  
// output.writeLong(nPos); KfpDPwP@  
output.writeLong(fileSplitterFetch.nStartPos); OU+oS,  
output.writeLong(fileSplitterFetch.nEndPos); PGZ.\i  
} kb<Nuw  
output.close(); u=B_cA}:  
} 9An_zrJ%i  
catch(IOException e){e.printStackTrace ();} fRKO> /OT  
catch(Exception e){e.printStackTrace ();} GFd~..$  
} -AwR$<q'  
jR<yV  
`M?C(  
//读取保存的下载信息(文件指针位置) c|q!C0X[  
private void read_nPos() @7 xb/&N  
{ IxC/X5Mp^q  
try{ (,$ H!qKy  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); DueQ1+ P  
int nCount = input.readInt(); 2Wz/s 0`  
nStartPos = new long[nCount]; ~@=:I  
nEndPos = new long[nCount]; 5fi6>>  
for(int i=0;i<nStartPos.length;i++) K|$Dnma^n  
{ ^)=c74;;  
nStartPos = input.readLong(); ]UyIp`nV;  
nEndPos = input.readLong(); Qo+_:N  
} pjr,X+6o  
input.close(); yP2[!vYw  
} }5dYmny  
catch(IOException e){e.printStackTrace ();} :_v/a+\n  
catch(Exception e){e.printStackTrace ();} SpbOvY=>  
} et]- ;(M  
\ F=w~ $)  
"<b~pfCOQk  
private void processErrorCode(int nErrorCode) F*QZVg+<*X  
{ sOA!Sl  
System.err.println("Error Code : " + nErrorCode); I=)Hb?q T~  
} F[/Bp>P7  
~?&;nTwHe  
2b+cz  
//停止文件下载 /zZ$<mVG  
public void siteStop() kOR5'rh  
{ Y; =y-D  
bStop = true; h-`Jd>u"  
for(int i=0;i<nStartPos.length;i++) w6>'n }  
fileSplitterFetch.splitterStop(); NikY0=i  
!f\,xa|M  
%Y8#I3jVJ  
} q,-bw2   
} pUby0)}t  
//负责部分文件的抓取 hKv3;jcd  
**FileSplitterFetch.java UlQZw*ce  
*/ ]$/TsN  
package NetFox; (!kOM% 3{  
KB+,}7  
S)Cd1`Gf  
import java.io.*; B:qH7`s  
import java.net.*; HrQBzS  
s hjb b  
j48cI3C  
public class FileSplitterFetch extends Thread { hEAt4z0P  
[su2kOX|X  
kSGFLP1FN  
String sURL; //File URL }{;m:Iia_  
long nStartPos; //File Snippet Start Position J =o,: 3"  
long nEndPos; //File Snippet End Position K FV&Dt}<  
int nThreadID; //Thread's ID [ 9)9>-  
boolean bDownOver = false; //Downing is over m=i8o `  
boolean bStop = false; //Stop identical E>~DlL%  
FileAccessI fileAccessI = null; //File Access interface [FLRrTcE  
cy|]}n85  
Nzj7e 1=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [L h<k+  
{ @dE|UZ=(  
this.sURL = sURL; 9d{iq"*R  
this.nStartPos = nStart; %RA8M- d  
this.nEndPos = nEnd; {>[,i`)  
nThreadID = id; :9H=D^J  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [eL?O;@BD  
} fis**f0  
2= FGZa*.  
fk-zT  
public void run() W6f?/{Oo8  
{ [*zB vj}G  
while(nStartPos < nEndPos && !bStop) HFYN(nz}[  
{ qPsf`nI7  
u '-4hU  
TR3_!0  
try{ +')\,m "z  
URL url = new URL(sURL); Sz4YP l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )70-q yA  
httpConnection.setRequestProperty("User-Agent","NetFox"); `*nVLtT Y  
String sProperty = "bytes="+nStartPos+"-"; D?~`L[}I!}  
httpConnection.setRequestProperty("RANGE",sProperty); BeZr5I"`}  
Utility.log(sProperty); mk?&`_X1  
6W&huIQ[  
nQ>?{"  
InputStream input = httpConnection.getInputStream(); Dp|y&x!  
//logResponseHead(httpConnection); =$3]%b}  
8Z{&b,Y4L  
b%<-(o/  
byte[] b = new byte[1024]; bL\ab  
int nRead; O'y8[<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) yHL2 !  
{ E5"%-fAJ  
nStartPos += fileAccessI.write(b,0,nRead); b:Oa4vBa  
//if(nThreadID == 1) En$-,8\%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F?Cx"JYix  
} _r+2o-ZR  
$(pzh:|  
{HPKp&kl  
Utility.log("Thread " + nThreadID + " is over!"); Ft)7Wx" S  
bDownOver = true; T+p ?VngF  
//nPos = fileAccessI.write (b,0,nRead); 1,,kU  
} t|q@~B :  
catch(Exception e){e.printStackTrace ();} dH"wYMNL  
} ?&?gQ#\N_J  
} Hq'mv_}qG  
(0/g)gW  
%>^CD_[eO  
//打印回应的头信息 0NlC|5ma)  
public void logResponseHead(HttpURLConnection con) 9xL8 ];-  
{ M3- bFIt  
for(int i=1;;i++) F|\^O[#R  
{ x*GGO)r  
String header=con.getHeaderFieldKey(i); nxH+XHv  
if(header!=null) TZ8:3ti  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m'D_zb9+  
Utility.log(header+" : "+con.getHeaderField(header)); Y?Ph%i2E  
else ?HT+| !4p  
break; \x D.rBbt  
} %D|p7&  
}  ,r\  
O ;,BzA-n  
@ *W)r~ "~  
public void splitterStop() * S4IMfp  
{ 1fwjW0t  
bStop = true; ]6)^+(zU  
} "w3#2q&  
pC<~\RR  
1FC'DH!  
} A/eZnsk  
07pASZ;~  
( <~  
/* *`.h8gTD,  
**FileAccess.java bHx09F]  
*//文件访问(定位,写) r}>8FE9S'H  
package NetFox; )EQWc0iKG  
import java.io.*; "b)Y5[nW  
vsc)EM ]  
+o+e*B7Eh  
public class FileAccessI implements Serializable{ NN(ZH73  
t5 :4'%|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 n.+%eYM<  
RandomAccessFile oSavedFile; z8v]Kt&  
long nPos; GZY8%.1{"a  
9z>I&vcX  
:&*Y Io  
public FileAccessI() throws IOException *d%"/l^0  
{ @'UbTB!  
this("",0); wuRB[KLe  
} -E, d)O`;$  
M\4pTcz{  
SMX70T!'9  
public FileAccessI(String sName,long nPos) throws IOException 3$x[{\ {  
{ N|t!G^rP  
oSavedFile = new RandomAccessFile(sName,"rw"); D c5tRO  
this.nPos = nPos; dw'&Av' |E  
oSavedFile.seek(nPos); 2d1Z;@x  
} 5]_m\zn=  
xz!b@5DR'%  
1Pya\To,m  
public synchronized int write(byte[] b,int nStart,int nLen) _:(RkS!x  
{ OR84/^>  
int n = -1; 2% ],0,o  
try{ ./SDZ:5/  
oSavedFile.write(b,nStart,nLen); xi5G?r  
n = nLen; Da.eVU;  
} U$zd3a_(  
catch(IOException e) lG[@s 'j  
{ -G\svwv@)  
e.printStackTrace (); $;GH -+  
} Vl"20):  
<%d/"XNg[D  
|"}F cS y  
return n; Vf28R,~m  
} c~1+5&  
0PfjD  
B49: R >  
} 6-"@j@l5<  
ky2n%<0]  
'mwgHo<u  
/* Q,pnh!.-c  
**SiteInfoBean.java "==fWf  
*/ v)+E!"R3.  
package NetFox; jh7-Fl`  
B{}<DP.  
NUSb7<s,&Y  
public class SiteInfoBean { D\13fjjHlu  
1 8*M  
*dmB Ji}  
private String sSiteURL; //Site's URL m5c=h  
private String sFilePath; //Saved File's Path OKW}8qM  
private String sFileName; //Saved File's Name z@za9U`6i  
private int nSplitter; //Count of Splited Downloading File nZtMF%j'  
,\fp .K<  
zx #HyO[a  
public SiteInfoBean() mVaWbR@HS  
{//nSplitter的缺省值为5 %:/@1r7o>  
//default value of nSplitter is 5 g&E3Wc  
this("","","",5); I 68Y4s  
} hQWo ]WF(J  
>z #^JR\6  
pW[KC!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [P:+n7= ,l  
{ io&FW!J.  
sSiteURL= sURL; JxP&znng  
sFilePath = sPath; fBj-R~;0  
sFileName = sName; %P8*Az&]T  
this.nSplitter = nSpiltter; ,J*C'#sW  
l & A8P  
e]9Z]a2  
} P/!W']OO  
\ 8v^ hb  
qV$\E=%fhM  
public String getSSiteURL() [SKN}:D  
{ 0Dt-!Q7  
return sSiteURL; Jn:h;|9w  
} S4ys)!V1V  
T]_]{%z  
"26=@Q^Y  
public void setSSiteURL(String value) R$|"eb5  
{ yg@8&;bP`  
sSiteURL = value; o=zr]vv  
} C@o8C%o  
#Sc9&DfX  
o=]\Jy  
public String getSFilePath() MlKSjKl" !  
{ ^RI& `5g  
return sFilePath; A<s zY92&5  
} k_?Z6RE>  
1 ORA6  
h_>DcVNIx  
public void setSFilePath(String value) .ZtW y) U  
{ [d?tf  
sFilePath = value; ;T\+TZtI  
} dZWO6k9[H  
saa3BuV 6  
5:yRFzhqd  
public String getSFileName() #c%F pR4  
{ v ^R:XdH  
return sFileName; f1$'av  
} <9dfbI)  
YB}m1 g`  
4{lrtNd~K  
public void setSFileName(String value) ^TZ`1:oL#  
{ cjp~I/U  
sFileName = value; ,f@\Fs~n  
} xNd p]u  
Oq9E$0JW  
w/f?KN  
public int getNSplitter() ,,c+R?D  
{ ?E}9TQ  
return nSplitter; 0-Ga2Go9  
} =91wC  
d-cW47  
e>T;'7HSS"  
public void setNSplitter(int nCount) ^wIg|Gc  
{ i5 0c N<o  
nSplitter = nCount; *S<d`mp[  
} z&c|2L-u6  
} |)65y  
*x-@}WY$U  
/O}lSXo6E  
/* : i{tqY%  
**Utility.java <MyT ;  
*/ B,fVNpqo  
package NetFox; 8n,/hY>w  
LC, 6hpmh  
Bra}HjHO  
public class Utility { -#Ys67,4N  
JJHO E{%  
9Ca }+  
public Utility() b_vKP  
{ xj[v$HP  
LzQOzl@z  
5AK@e|G$w  
} Itz[%Dbiq9  
8#nAs\^  
//线程睡眠 &n'@L9v81  
public static void sleep(int nSecond) IhHKRb[  
{ VkkC;/BBW  
try{ Jsa]RA  
Thread.sleep(nSecond); ,4j^ lgJ  
} E?0Vo%Vh  
catch(Exception e) f hjlt#  
{ H+ 7HD|GE  
e.printStackTrace (); tIT/HG_o  
} y8ODoXk  
} ,R\ex =c  
N*f ]NCSi  
//日志 w\RYxu?  
public static void log(String sMsg) jcp6-XM  
{ 25j?0P"&  
System.err.println(sMsg); d%K&  
} V-(*{/^"  
D}`MY\H  
e>m+@4*sn  
public static void log(int sMsg) t$3B#=  
{ wBJ|%mc3TA  
System.err.println(sMsg); QM'|k6  
} \fsNI T/  
} rvacCwI  
yAFt|<  
;\(LovUy6  
/* CofTTYl  
**TestMethod.java lA` qB1x  
*/ d`,z4 _  
package NetFox; l{gR6U{e  
i#aKW'  
o)GesgxFa5  
public class TestMethod { #w@FBFr@  
|\Q2L;4C  
YwS/O N  
public TestMethod() &Oc `|r*  
{ ///xx/weblogic60b2_win.exe fR b  
try{ h$XoR0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); !sp`oM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q"5\bh1"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'ka}x~EF  
fileFetch.start(); rd;E /:`5  
} #uV J  
catch(Exception e){e.printStackTrace ();} ;9Qxq]  
|~@yXc5a  
P!SsMo6n  
} $:yIe.F  
vJ{F)0 K  
F1S0C>N?5  
public static void main(String[] args) v 8EI   
{ Nt;1&dwUb  
new TestMethod(); 1*e7NJ/.,  
} dlA0&;}z  
} X f{9rZ+  
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