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http断点续传简单实现(java)

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/* ` U-vXP  
**SiteFileFetch.java Et0)6^-v  
*/ yvnDS"0<  
package NetFox; $PAAmaigi  
import java.io.*; !Ce!D0Tx  
import java.net.*; .2s^8gO  
*2rc Y  
tGzp= PyA  
public class SiteFileFetch extends Thread { ayQeT  
drk BW}_  
Od:-fw  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^P*-bV4  
long[] nStartPos; //开始位置 ~qIr'?D  
long[] nEndPos; //结束位置 f^ZhFu?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Dwr 9}Z-]  
long nFileLength; //文件长度 Bf6i{`!G  
boolean bFirst = true; //是否第一次取文件 E+LQyvF[  
boolean bStop = false; //停止标志 cOZBl;}  
File tmpFile; //文件下载的临时信息 +S`cUn7  
DataOutputStream output; //输出到文件的输出流 !IA\c(c^  
.!Kqcz% A  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) \CV HtV  
public SiteFileFetch(SiteInfoBean bean) throws IOException j%Xa8$  
{ "a3?m)  
siteInfoBean = bean; H8=:LF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !l Egta[Ql  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F ^aD#  
if(tmpFile.exists ()) Tku6X/LF  
{ g"(@+\XZH"  
bFirst = false; =\oL'>q  
read_nPos(); gVI`&W__,  
} ~*9Ue@  
else L]u^$=rI  
{ P}qpy\/(4  
nStartPos = new long[bean.getNSplitter()]; _:WNk(  
nEndPos = new long[bean.getNSplitter()]; x+;y0`oL  
} =N8_S$nx(  
FOsxId[f9  
jA[Ir3  
>EZZEd   
} - ZyY95E<  
M ?AX:0  
8FZC0j.^DH  
public void run() s@{~8cHgU  
{ ^E:-Uy  
//获得文件长度 ByO?qft>u  
//分割文件 m7C!}l]9  
//实例FileSplitterFetch 3,X8 5`v^  
//启动FileSplitterFetch线程 CC;^J-h/  
//等待子线程返回 bN03}&I  
try{ D.|r [c  
if(bFirst) A*A/30o|R  
{ 3vjOfr`  
nFileLength = getFileSize(); dv+ZxP%g  
if(nFileLength == -1) $mE3 FJP>  
{ *?]<=IV?  
System.err.println("File Length is not known!"); c b&Yf1  
} /&_q"y9  
else if(nFileLength == -2) BG= J8  
{ {@3v$W~7M  
System.err.println("File is not access!"); E^br-{|{  
} ';My"/ Z-  
else +6 =lN[b  
{ mfS}+_ C  
for(int i=0;i<nStartPos.length;i++) ZS;V?]\(  
{ q-ko)]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); he:z9EG}  
} W$()W)   
for(int i=0;i<nEndPos.length-1;i++) `wQs$!a  
{ }f14# y;  
nEndPos = nStartPos[i+1]; xkax  
} G6}&k[d5%  
nEndPos[nEndPos.length-1] = nFileLength; DwZRx@  
} URg;e M#  
} :#35mBe}k  
w0lgB%97p  
(Y8 LyY  
//启动子线程 =QbOvIq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nE*S3  
for(int i=0;i<nStartPos.length;i++) sQ,xTWdj  
{ LExm#T`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !{+.)%d'g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), '`. -75T  
nStartPos,nEndPos,i); v9Sk\9}S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 32?'jRN(ue  
fileSplitterFetch.start(); / o I 4&W  
} /3K)$Er  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 19c_=$mV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &qWB\m  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  -gS9I^  
nEndPos = " + nFileLength); P}UxA!  
// fileSplitterFetch[nPos.length-1].start(); H9_iTGBQ  
2f@Cy+W'[  
m'"H1~BW  
//等待子线程结束 l>`66~+s,`  
//int count = 0; }^$1<GT  
//是否结束while循环 Ry"4v_e9  
boolean breakWhile = false; #+V4<o  
cL ~WDW/  
-,T!/E  
while(!bStop) V,0$mBYa  
{ Wf"GA i  
write_nPos(); OKK Ko`RN  
Utility.sleep(500); D4|Ajeo;1  
breakWhile = true; /4 OmnE;  
"~._G5i.  
{i?G:K  
for(int i=0;i<nStartPos.length;i++) ge.>#1f}  
{ KK2YT/K$SG  
if(!fileSplitterFetch.bDownOver) !4=_l6kg~+  
{ ^v'0\(H?P  
breakWhile = false; G.~ Q2O#T  
break; REE .8_  
} L 6fbR-&Lt  
} strM3j##x  
if(breakWhile) 2,`X@N`\  
break; $fT5Vc]B4  
f\_PNZCc  
3nc\6v%  
//count++; O6)Po  
//if(count>4) .m l\z5  
// siteStop(); KsE$^`  
} oe2*$\?.  
u_ l?d  
/.CS6W^z  
System.err.println("文件下载结束!"); %=9o'Y,4  
} Z|Rc54Ct  
catch(Exception e){e.printStackTrace ();} @KU;' th  
} 1zH?.-  
'N+;{8C-{  
W&R67ff|  
//获得文件长度 @4 8!e-W  
public long getFileSize() R6o  D  
{ KCw  
int nFileLength = -1; QOYMT( j  
try{ 2w8cJadT'p  
URL url = new URL(siteInfoBean.getSSiteURL()); w43b=7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4:NMZ `~  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^Cp2#d*  
N\B&|;-V  
h ~yTkN]  
int responseCode=httpConnection.getResponseCode(); #)xlBq4cZ  
if(responseCode>=400) 8tQL$CbO  
{ <nD@4J-A0  
processErrorCode(responseCode); [~ 2m*Q  
return -2; //-2 represent access is error :??W3ROn  
} #&?ER]|3  
-d#08\  
[r8[lkR  
String sHeader; {.A N4  
;hO6 p  
_.V5-iN  
for(int i=1;;i++) ~5%3]  
{ JZ`h+fAt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); g =Xy{Vm  
//Utility.log(in.readLine()); UCfouQCj  
sHeader=httpConnection.getHeaderFieldKey(i); W}TP(~x'N  
if(sHeader!=null) (?R!y -  
{ M(K7xx+G  
if(sHeader.equals("Content-Length")) .\ fpjQW  
{ ?{aJ#w   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); rC_1f3A  
break; pgh(~ [  
} K;sC#9m  
} SsW<,T  
else Aipm=C8  
break; cxSHSv 1;  
} I8)D   
} {m~)~/z?  
catch(IOException e){e.printStackTrace ();} #2ta8m),  
catch(Exception e){e.printStackTrace ();} MooH`2Fd  
6A]I" E]5  
6P717[  
Utility.log(nFileLength); DMG'8\5C  
.Vnb+o  
4 xbWDu]  
return nFileLength; =dA] nM  
} -i{_$G8W/c  
#U L75  
>wmHCOL:  
//保存下载信息(文件指针位置) C 4C /  
private void write_nPos() ^U5N!"6R  
{ i56Rdb  
try{ FsWp>}o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); WVpx  
output.writeInt(nStartPos.length); Oj_]`  
for(int i=0;i<nStartPos.length;i++) qna!j|90Lp  
{ )M+po-6$1  
// output.writeLong(nPos); {!wW,3|Pu  
output.writeLong(fileSplitterFetch.nStartPos); HYGd :SeH  
output.writeLong(fileSplitterFetch.nEndPos); p:y\{k"  
} =O0A(ca"g  
output.close(); Vlz\n  
} Lg!E  
catch(IOException e){e.printStackTrace ();} K=0xR*ll5  
catch(Exception e){e.printStackTrace ();} 4sQm"XgE  
} :FS5BT$=  
b7\>=  
fb`x1Q  
//读取保存的下载信息(文件指针位置) c:.5@eq^  
private void read_nPos() "kFH*I+v  
{ pIC'nO_  
try{ +vxf_*0;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \)t//0  
int nCount = input.readInt(); d;l%XZe  
nStartPos = new long[nCount]; sGhw23  
nEndPos = new long[nCount]; !nkIXgWz  
for(int i=0;i<nStartPos.length;i++) r/AOgS  
{ ^0|:  
nStartPos = input.readLong(); i'H]N8,A  
nEndPos = input.readLong(); F}45.C rD  
} gdTW ~b  
input.close(); ]R)wBug  
} ZwsQ}5  
catch(IOException e){e.printStackTrace ();} `9[n5-t  
catch(Exception e){e.printStackTrace ();} B3&C&o.h  
} ddKP3}  
BT8)t.+pv  
:s_.K'4?a  
private void processErrorCode(int nErrorCode) : H;S"D  
{ Ot-P J i  
System.err.println("Error Code : " + nErrorCode); {Dl@/fz  
} z;oia!9z  
TIiYic!_~  
\MRd4vufv  
//停止文件下载 oc] C+l  
public void siteStop() Ds"%=  
{ _ncBq;j{  
bStop = true; DKfpap}8u  
for(int i=0;i<nStartPos.length;i++) VNT?  
fileSplitterFetch.splitterStop(); WM|G/'q  
fTPm Fb  
iZfZF  
} Sdmz (R  
} PjBAf'  
//负责部分文件的抓取 , v} )  
**FileSplitterFetch.java q&>fKSnKs  
*/ 1O0. CC,p  
package NetFox; G) KI{D  
hmkb!)  
ZKEoU!  
import java.io.*; 2! ,ndLA  
import java.net.*; 9Jh&C5\\  
0~BaQ, A @  
E3j`e>Yz  
public class FileSplitterFetch extends Thread { ?sdSi--  
tDL.+6/  
fK=0?]s}I  
String sURL; //File URL qypF}Pw  
long nStartPos; //File Snippet Start Position *s 4Ym  
long nEndPos; //File Snippet End Position I ]o|mjvs  
int nThreadID; //Thread's ID Q ]TZyk  
boolean bDownOver = false; //Downing is over tKUW  
boolean bStop = false; //Stop identical yW'{Z]09  
FileAccessI fileAccessI = null; //File Access interface [Lje?M* r  
L:Rg3eo  
+8Q @R)3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException CtN\-E-  
{ wg)Bx#>\L:  
this.sURL = sURL; B/a`5&G]  
this.nStartPos = nStart; Xykoq"dbb  
this.nEndPos = nEnd; ^"|q~2  
nThreadID = id; Ey: ?!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "Y:>^F;  
} &Wa3/mWK  
azIhp{rH w  
i@rUZYF  
public void run() l#v52  
{ z{ eZsh b  
while(nStartPos < nEndPos && !bStop) jSvq1$U  
{ J#Y0R"fo  
$*X?]?  
DjK7_'7(L  
try{ :l]qTCmY  
URL url = new URL(sURL); n.9k5r@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); g`'!Vgd?M[  
httpConnection.setRequestProperty("User-Agent","NetFox"); Brs6RkRf  
String sProperty = "bytes="+nStartPos+"-"; ~fD\=- S1  
httpConnection.setRequestProperty("RANGE",sProperty); DTA$,1JuD  
Utility.log(sProperty); x f{`uHa8  
9O&gR46.  
R[\1Kk(Zo  
InputStream input = httpConnection.getInputStream(); ylczM^@  
//logResponseHead(httpConnection); Q]=/e7  
\='LR!_  
JL#LCU ?  
byte[] b = new byte[1024]; 6 M:?W"  
int nRead; 1SS1P0Ur  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6;Z`9PGp  
{ YJ ,"@n_  
nStartPos += fileAccessI.write(b,0,nRead); iNkN'("  
//if(nThreadID == 1)  ~ e?af  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QlB9m2XB  
} )=gU~UV  
*ilVkV"U  
q)?!]|pZ  
Utility.log("Thread " + nThreadID + " is over!"); }[|9vF"g.y  
bDownOver = true; [g}#R#Y)  
//nPos = fileAccessI.write (b,0,nRead); vde!k_,wZ  
} ^"I@ 8k  
catch(Exception e){e.printStackTrace ();} w+ ')wyB  
} YBj*c$.D0  
}  yI|x 5f  
F;`c0ja]  
HFjSM~  
//打印回应的头信息 8*b{8%<K  
public void logResponseHead(HttpURLConnection con) T&/ n.-@nk  
{ cz/ E  
for(int i=1;;i++) fCNQUK{Gs5  
{ e}{#VB<  
String header=con.getHeaderFieldKey(i); 9C?SEbC  
if(header!=null) b 4^O=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |H5GWZ O{^  
Utility.log(header+" : "+con.getHeaderField(header)); a8)2I~j  
else ]Zh$9YK  
break; M __S)  
} FsOJmWZ  
} w3 vZ}1|  
1l)j(,Zd*  
7&P70DO  
public void splitterStop() pFMjfWD,C  
{ NL|c5y<r  
bStop = true; 7P2(q  
} 71E~~$  
0s//&'*Q  
$'>iNMtK{p  
} .?APDr"QQH  
\6 JY#%  
<tZtt9j_  
/* ?m 5"|f\  
**FileAccess.java 'z}9BGR !  
*//文件访问(定位,写)  ZaaBg  
package NetFox; 4w9=z,  
import java.io.*; d5LBL'/o  
6v scu2  
_0u=}tc  
public class FileAccessI implements Serializable{ E|-5=!]fX  
nnBS;5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 hFycSu  
RandomAccessFile oSavedFile; ~~&Bp_9QXN  
long nPos; $D65&R  
=os!^{p7>  
JDa_;bqL  
public FileAccessI() throws IOException POl-S<QV  
{ E[ -yfP~[  
this("",0); C%<Dq0j  
} (  -q0!]E  
$tW E9_  
%}N01P|X>  
public FileAccessI(String sName,long nPos) throws IOException  y"Fu=  
{ _?felxG[  
oSavedFile = new RandomAccessFile(sName,"rw"); %LHt{:9.  
this.nPos = nPos; njJTEUd">  
oSavedFile.seek(nPos); 7Cz=;  
} d^~yUk  
Rq2bj_j  
h*<`ct xL  
public synchronized int write(byte[] b,int nStart,int nLen) v0&DD&mp  
{ :0%[u(  
int n = -1; dj] O  
try{ ^Ar1V!PFk  
oSavedFile.write(b,nStart,nLen); .i )K#82  
n = nLen; u&={hJ&7  
} >_]Ov:5  
catch(IOException e) # ^,8JRA  
{ /8:e| ]  
e.printStackTrace (); ,'Y KL",  
} nzAySMD_  
{_4Hsw?s6  
s H'FqV,)  
return n; 8* m,#   
} z\, lPwB2  
! B`  
|Om][z  
} hqHk,#  
K0'p*[yO/j  
V1nqEdhk  
/* &q-P O  
**SiteInfoBean.java ,=@WE> ip  
*/ d8 v9[ 4  
package NetFox; V$$9Rh  
79 _8Oh  
AYoTCi%7E  
public class SiteInfoBean { "\~>[on  
M`=\ijUwN  
g=v'[JPd  
private String sSiteURL; //Site's URL &,Rye Q  
private String sFilePath; //Saved File's Path 7?_g m>]a  
private String sFileName; //Saved File's Name k&K'FaM!  
private int nSplitter; //Count of Splited Downloading File {<Y!'WL{  
1 Cz}|#U  
eUu<q/FUMj  
public SiteInfoBean() ~(c<M>Q8  
{//nSplitter的缺省值为5 :SMf (E 5  
//default value of nSplitter is 5 1z,P"?Q  
this("","","",5); O]="ggq&  
} =NK'xPr  
&jnBDr  
P()&?C  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) rnMi >?  
{ )`|`PB  
sSiteURL= sURL; / a}N6KUi  
sFilePath = sPath; Zl!  
sFileName = sName; #QOb[9(Tu(  
this.nSplitter = nSpiltter; d[;&2Jz*  
%[L/JJbP&Z  
& R<K>i  
} HDE5Mg "  
]d|M@v~c4  
*ZRk)  
public String getSSiteURL() 6khm@}}  
{ W8]?dL}|  
return sSiteURL; Qe9}%k6@E  
} uE,T Ea9;  
^MhMYA  
B/~ubw  
public void setSSiteURL(String value) Gh3f^PWnc  
{ $b_~  
sSiteURL = value; 7Y 4D9pw  
} Csgby(D*O  
=@P(cFJ/  
8JMxA2tZhG  
public String getSFilePath() n-wOLH  
{ H\<PGC"_Y  
return sFilePath; |`I9K#w3  
} }U%E-:  
-=u9>S)!c  
#H8QX5b)  
public void setSFilePath(String value) YAi@EvzCVy  
{ 9(a*0H  
sFilePath = value; Q"LlBp>t|#  
} _$}@hD*R~  
0@&;JMh6<  
^d9o \  
public String getSFileName() ^@'zQa  
{ [[4!b E  
return sFileName; 3)^ 2X  
} zJ8jJFL+Y  
S~g "  
$qoal   
public void setSFileName(String value) Y\(?&7Aax  
{ puF*WxU)  
sFileName = value; #Oa`P  
} h9. Yux  
Sn;q:e3i{A  
nu16L$ ]  
public int getNSplitter() P^BSl7cT  
{ 3[kl` *`  
return nSplitter; ZGd7e.u=  
} #g Rns  
yzG BGC  
Zc9S[ivq  
public void setNSplitter(int nCount) eQ#"-i  
{ LXc;`]  
nSplitter = nCount; _UF'Cf+Y  
} kRiZ6mn  
} Ao9|t;i  
T(kG"dz   
p|)j{nc  
/* gF~ }  
**Utility.java 0}Q d  
*/ fAT M?  
package NetFox; |'L$ogt6  
'EU|w,GL}  
8PRB_ny  
public class Utility { 5XNFu C9E  
m?1AgsBR  
uKT\\1Jrq  
public Utility() {~=gKZ:-@  
{ D rouEm  
yyjgPbLN=  
61z^(F$@  
} z8PV&o  
W%#LHluP  
//线程睡眠 Y;sN UX  
public static void sleep(int nSecond) ,fs>+]UY3  
{ \mwxV!!b$  
try{  !h* F58  
Thread.sleep(nSecond); wA%,_s/U  
} dM5N1$1,  
catch(Exception e) QnH~' k  
{ I9cZZ`vs  
e.printStackTrace (); ~0{F,R.$  
} m8v=pab e  
} :\#/T,K"  
]=5D98B  
//日志 ~uO9>(?D  
public static void log(String sMsg) m\|ie8  
{ RLF]Wa,  
System.err.println(sMsg); -s6;IoG/  
} Rd+ `b  
>!P !F(  
"Ze<dB#,Y  
public static void log(int sMsg) _ 3jY,*  
{ `vrLFPdO  
System.err.println(sMsg); % wh>_Ho  
} ?OWJUmQ  
} TSP#.QY  
|?uUw$oh  
X>rv{@KbL  
/* K1fnHpK  
**TestMethod.java qH*Fv:qnM  
*/ ^:m7Qd?Z[  
package NetFox; \;Q:a /ur9  
#mcGT\tQ  
q6N6QI8/  
public class TestMethod { 'Y-Y By :  
2NqO,B|R  
p GSS   
public TestMethod() iED gcg7  
{ ///xx/weblogic60b2_win.exe " [K>faV  
try{ ' sTMUPg`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); G9a6 $K)b  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {rZ )!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4VfZw\^  
fileFetch.start(); 25jgM!QBXF  
} X\LiV{c  
catch(Exception e){e.printStackTrace ();} | D,->k  
i}e OWi  
x-=qlg&EI  
} dy2<b+ ..  
8 gzf$Oc  
p EbyQ[  
public static void main(String[] args) S9S%7pE  
{ xy1R_*.F^T  
new TestMethod(); y[sO0u\  
} 8Ir = @  
} [cf!%3>53  
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