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http断点续传简单实现(java)

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/* K\KO5A  
**SiteFileFetch.java oBj>9I;  
*/ NB+$ym  
package NetFox; 1R2o6`_  
import java.io.*; =WmBpUh  
import java.net.*; o7Cnyy#:  
yxCM l.  
k?["F%)I  
public class SiteFileFetch extends Thread { ^\ vfos  
)7I.N]=  
UN*dU  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1akD]Z  
long[] nStartPos; //开始位置 YMj7  
long[] nEndPos; //结束位置 )&Kn (l)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ayH%  qp  
long nFileLength; //文件长度 !$p2z_n$@.  
boolean bFirst = true; //是否第一次取文件 T$n>7X-r  
boolean bStop = false; //停止标志 wWJQ ~i?  
File tmpFile; //文件下载的临时信息 %Rd~|$@>x  
DataOutputStream output; //输出到文件的输出流 ]{AOh2Z.hv  
3{Ek-{ 9  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) JA?,0S  
public SiteFileFetch(SiteInfoBean bean) throws IOException a(}VA|l  
{ GP{$v:RG  
siteInfoBean = bean; "rjv5*z^&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "#-Nqq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); mmrW`~-  
if(tmpFile.exists ()) lPRdwg-  
{ h;EwkbDQg>  
bFirst = false; .#=j <&  
read_nPos(); ;.nP%jD  
} FVsu8z u  
else POqRHuFq  
{ u=@h`5-fp  
nStartPos = new long[bean.getNSplitter()]; (#j2P0B  
nEndPos = new long[bean.getNSplitter()]; Gut J_2f^9  
} {?EEIfg  
VY+(,\ )U  
\~gA+ o}Q  
NJ|NJ p&0  
} H _Zo@y~J  
cg(QjH"  
( }]37  
public void run() #*yM2H"7,;  
{ ASzzBR;?_  
//获得文件长度 ^8?j~&u$F  
//分割文件 ="3a%\  
//实例FileSplitterFetch (orrX Ez  
//启动FileSplitterFetch线程 |5 oKq'(b  
//等待子线程返回 {yvb$ND|j{  
try{ Y!++C MzU  
if(bFirst) Y<p zy8z  
{ pu/m8  
nFileLength = getFileSize(); F=oHl@  
if(nFileLength == -1) WF ?/GN  
{ T!u'V'Ei2  
System.err.println("File Length is not known!"); zW"~YaO%C  
} @9OeC O  
else if(nFileLength == -2) G 2%  
{ [;(]Jy  
System.err.println("File is not access!"); OW+e_im}  
} v}7@CP]nV  
else P]pmt1a  
{ O" % Hprx  
for(int i=0;i<nStartPos.length;i++) tWpl`HH  
{ KI E k/]<H  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gCv"9j<j  
} Dk)@>l:gI,  
for(int i=0;i<nEndPos.length-1;i++) `fQM  
{ `t{D7I7  
nEndPos = nStartPos[i+1]; {E!$ xY8  
} _:wZmZU}  
nEndPos[nEndPos.length-1] = nFileLength; p>k]C:h  
} lZ}izl  
} LQh^; ]^(  
VDB$"T9#  
a`7%A H)  
//启动子线程 OOCQsoN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E^b pckP  
for(int i=0;i<nStartPos.length;i++) Dz[566UD  
{ yB-.sGu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n=f`AmF;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), iKg75%;t  
nStartPos,nEndPos,i); "#*Nnt  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EKc C+g   
fileSplitterFetch.start(); %  2I  
} "Jb3&qdU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jmkRP"ZnA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e Wc_N  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", y7CWBTH0>  
nEndPos = " + nFileLength); 5B}3GBA  
// fileSplitterFetch[nPos.length-1].start(); ( FM4 ^#6  
@q,)fBZq  
Q 2*/`L}m\  
//等待子线程结束 N1PECLS?  
//int count = 0; O x{Q.l  
//是否结束while循环 |kId8WtA  
boolean breakWhile = false; q#;BhPc  
m'd^?Qc  
;xL67e%?  
while(!bStop) h]qT1( I  
{ F vj{@B!  
write_nPos(); + Qt[1Xq  
Utility.sleep(500); !d\t:0;  
breakWhile = true; ,,S9$@R  
K6E}";;  
!]yQ1@)*'  
for(int i=0;i<nStartPos.length;i++) rqF"QU=l  
{  G]b8]3^  
if(!fileSplitterFetch.bDownOver) mj)PLZ]  
{ i#k-)N _$  
breakWhile = false; H\ 3M  
break; _HwpPRVP/  
} ]22C )<  
} qc3~cH.@  
if(breakWhile) ])C>\@c6Gm  
break; >b'w'"  
qB+n6y%  
&(g|="T  
//count++; PJCnud F  
//if(count>4) G=1m] >I8  
// siteStop(); -)X{n?i  
} w5,6$#  
RYt6=R+f  
rw&y,%2  
System.err.println("文件下载结束!"); }f0u5:;Zth  
} JfkTw~'R  
catch(Exception e){e.printStackTrace ();} q'.;W@m  
} ( ]OFS;%  
f7Zf}1|  
"MTWjW*6  
//获得文件长度 z4g+2f7h-X  
public long getFileSize() eO'xkm  
{ Ee8--  
int nFileLength = -1; }S,-uggz  
try{ #'C/Gya  
URL url = new URL(siteInfoBean.getSSiteURL()); ~^x-ym5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )U'yUUi  
httpConnection.setRequestProperty("User-Agent","NetFox"); IdF$Ml#[h  
4Hk6b09  
C,.-Q"juH  
int responseCode=httpConnection.getResponseCode(); HM):"  
if(responseCode>=400) y<|)'(  
{ h`lmC]X _  
processErrorCode(responseCode); lcCJ?!lsSW  
return -2; //-2 represent access is error 6%%PP8.F  
} 2 % %|fU9  
 [@<G+j  
u%xDsT DP  
String sHeader; U%q:^S%#eG  
WV2~(/hX&  
v{.\iIg N  
for(int i=1;;i++) O] H=s  
{ _#FIay\ahB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c#  xO<  
//Utility.log(in.readLine()); {|XQO'Wg  
sHeader=httpConnection.getHeaderFieldKey(i); a!D*)z Y  
if(sHeader!=null) GQ<Ds{exs>  
{ Y#`Lcg+r,  
if(sHeader.equals("Content-Length")) awFhz 6   
{ 9k}<Fz"^.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); O ^0"  
break; l DnMjK\M  
} Z:|9N/>T  
} VJg,~lQN#t  
else 7G"7wYc>R  
break; ,%Z&*n  
} AFm,CINa  
} XIRR Al(,  
catch(IOException e){e.printStackTrace ();} H*rx{F?  
catch(Exception e){e.printStackTrace ();} pqeL%="p;  
.gq(C9<B[  
<5I1DF[  
Utility.log(nFileLength); 5q Rc4d'  
r4?b0&Xq  
]26mB  
return nFileLength; JpmB;aL#%  
} ]n5"Z,K  
-;>#3 O-  
/l6\^Xf{  
//保存下载信息(文件指针位置) Yx),6C3  
private void write_nPos() ?q!FG(  
{ ~.6|dw\p!  
try{ Y\p $SN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FsY(02  
output.writeInt(nStartPos.length); qg4fR' i  
for(int i=0;i<nStartPos.length;i++) 72,"Cj  
{ +T2HE\  
// output.writeLong(nPos); Qci$YTwl>  
output.writeLong(fileSplitterFetch.nStartPos); 13a(FG  
output.writeLong(fileSplitterFetch.nEndPos); Gs_qO)~xo  
} 'gDe3@ci!  
output.close(); l E^*t`+  
} 5V@&o`!=h  
catch(IOException e){e.printStackTrace ();} e\9g->DUs  
catch(Exception e){e.printStackTrace ();} _!!}'fMC  
} VNj@5s  
]'k[u  
7~b!4x|Z  
//读取保存的下载信息(文件指针位置) !)c=1EX]"  
private void read_nPos() ],[)uTZc  
{ -CD\+d  "  
try{ +j[`,5oS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :Q-oV8t{  
int nCount = input.readInt(); d0 -~| `5  
nStartPos = new long[nCount]; @]=f?+y[ 2  
nEndPos = new long[nCount]; HE;V zR  
for(int i=0;i<nStartPos.length;i++) ZXt?[Ll  
{ C),7- ?  
nStartPos = input.readLong(); a4&:@`=  
nEndPos = input.readLong(); nm@']  
} %!y89x=E  
input.close(); `c(\i$1JY)  
} 8Z#21X>  
catch(IOException e){e.printStackTrace ();} AIh*1>2Xn  
catch(Exception e){e.printStackTrace ();} qS.)UaA  
} TnA?u (R%  
xo  Gb  
}1U*A#aN7K  
private void processErrorCode(int nErrorCode) `f)(Y1%.  
{ ,w2WS\`%  
System.err.println("Error Code : " + nErrorCode); b/<mRQ{  
} [AR>?6G-  
a2yE:16o6  
.X `C^z]+  
//停止文件下载 xU}M;4kH~  
public void siteStop() PLdn#S}.  
{ l>&sIX  
bStop = true; MEq"}zrh  
for(int i=0;i<nStartPos.length;i++) yC !/PQ"  
fileSplitterFetch.splitterStop(); {DBIonY];  
|0 !I5|<k  
<o0~H  
} 9y^/GwUQ  
} Sj-[%D*  
//负责部分文件的抓取 IU!Ht>  
**FileSplitterFetch.java kus}W  J  
*/ ;6m;M63z  
package NetFox; .Yx_:h=u  
ZL_[4 Y  
6y  Wc1  
import java.io.*; (oaYF+T  
import java.net.*; ]sj0~DI*m  
aB"xqh)a}T  
Rj6|Y"gq9  
public class FileSplitterFetch extends Thread { HZZDv+  
nl n OwyMJ  
#w>~u2W  
String sURL; //File URL 7[KCWJ  
long nStartPos; //File Snippet Start Position CWlW/>yF B  
long nEndPos; //File Snippet End Position o\6iq  
int nThreadID; //Thread's ID L"vj0@n'0  
boolean bDownOver = false; //Downing is over SW9fE :v  
boolean bStop = false; //Stop identical P`"mM?u  
FileAccessI fileAccessI = null; //File Access interface (V?@?25  
u) *Kws  
WRpyr  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException eVt1d2.O  
{ ?CY1]d  
this.sURL = sURL; x(~<tX~  
this.nStartPos = nStart; HI!4  
this.nEndPos = nEnd; OW`STp!  
nThreadID = id; Gv~p  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 T PYDs+U  
} M"wue*&  
Q~Ea8UT. #  
nvyB/  
public void run() 8;n_TMb  
{ 6E^~n  
while(nStartPos < nEndPos && !bStop)  `w<J25  
{ QUOKThY?  
sN/+   
l [%lE  
try{ (E!!pz  
URL url = new URL(sURL); Z'M`}3O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5DFZ^~  
httpConnection.setRequestProperty("User-Agent","NetFox"); #Ufo)\x  
String sProperty = "bytes="+nStartPos+"-"; 213\ehhG<  
httpConnection.setRequestProperty("RANGE",sProperty); >Ko[Xb-8^_  
Utility.log(sProperty); \ =nrt?  
36$[   
o""~jc~  
InputStream input = httpConnection.getInputStream(); KCtX $XGL  
//logResponseHead(httpConnection); &; >4N"]  
BSzkW}3q9  
qO()w   
byte[] b = new byte[1024]; {-WTV"L5*2  
int nRead; lhPGE_\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) C1fyV]  
{ v?j!&d>  
nStartPos += fileAccessI.write(b,0,nRead); Kf.T\V4%  
//if(nThreadID == 1) P))^vUt~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MCYl{uH!  
} JwP:2-o  
(vyz;Ob  
oNYZIk:  
Utility.log("Thread " + nThreadID + " is over!"); ( ?Q|s,  
bDownOver = true; `s /?b|,  
//nPos = fileAccessI.write (b,0,nRead); YQVcECj  
} K=\&+at1  
catch(Exception e){e.printStackTrace ();} Ijedo/  
} }5n  
} IZNOWX|Z;  
>D _F!_  
&drFQ|  
//打印回应的头信息 LWmB, Zf/  
public void logResponseHead(HttpURLConnection con) KoHGweKl#  
{ F ?=9eISLJ  
for(int i=1;;i++) !%S4 n  
{ }ug xN0  
String header=con.getHeaderFieldKey(i); d2jr8U  
if(header!=null) #`ejU&!6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :zp`6l  
Utility.log(header+" : "+con.getHeaderField(header)); "H+,E_&(  
else ijW 7c+yd  
break; ' 4 O-  
} PK:2xN:=  
} w^;DG  
o`?zF+M0  
>K)2NLW\xA  
public void splitterStop() I=rwsL  
{ Iti0qnBN5  
bStop = true; 7"Mk+'  
} >^SEWZ_[  
9&  
#oV+@D`  
} p'Bm8=AwD  
~W{-Q.  
Q5n`F5   
/* bToq$%sCg  
**FileAccess.java wCb(>pL0  
*//文件访问(定位,写) f[jN wb  
package NetFox; 4Z5#F]OA7  
import java.io.*; HEY4$Lf(I  
|>1hu1  
z2 hFn&  
public class FileAccessI implements Serializable{ aC^$*qN-)  
~5OL6Bi-q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ai-n z-;  
RandomAccessFile oSavedFile; -5Utl os  
long nPos; |b.z*G  
PCE4W^ns  
tP(h9|[N  
public FileAccessI() throws IOException P:{<*`q  
{ Qvqqvk_tv  
this("",0); ls|LCQPx  
} 82:Wvp6  
x` /)g(  
:tj-gDa\Y  
public FileAccessI(String sName,long nPos) throws IOException SbT5u3,'  
{ ;Yts\4BSM  
oSavedFile = new RandomAccessFile(sName,"rw"); Vfs $ VY2.  
this.nPos = nPos; !:0v{ZQ  
oSavedFile.seek(nPos); ^[q /Mw  
} Xs$Ufi  
j8$Zv%Ca%  
r`M6!}oa  
public synchronized int write(byte[] b,int nStart,int nLen) r4{<Z3*N  
{ |g&ym Fc  
int n = -1; [EZYsOr.  
try{ %&+59vq   
oSavedFile.write(b,nStart,nLen); HuI`#.MpWE  
n = nLen; \8v91g91f  
} *l+Cl%e  
catch(IOException e) wpo1  
{ ^k/i-%k0  
e.printStackTrace (); Op}ZB:  
} ^DAu5|--R  
0D~ Tga)  
|m* .LTO  
return n; Ciihsm  
} bbN%$/d  
;_"U "?h_J  
+c$I&JO  
} #@f[bP}a  
wWjG JvJ  
m7jA ,~O  
/* ukAKFc^)k  
**SiteInfoBean.java @wN G  
*/ o(G"k  
package NetFox;  xvm5   
h5~n 1qX  
]k%PG-9  
public class SiteInfoBean { dl|gG9u4Q  
P~ 0Jg# V  
:#{Xuy:  
private String sSiteURL; //Site's URL `!4,jd  
private String sFilePath; //Saved File's Path FfFak@H  
private String sFileName; //Saved File's Name +l 0g`:  
private int nSplitter; //Count of Splited Downloading File 93Yn`Av;  
SaDA`JmO  
"lVqU  
public SiteInfoBean() l|"6yB |  
{//nSplitter的缺省值为5 [M+tB"_  
//default value of nSplitter is 5 ,T5u'";  
this("","","",5); I0 Ia6w9  
} _eQ-`?  
>hsuAU.UOR  
[~mGsXV  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =JO^XwUOo  
{ Paf%rv2  
sSiteURL= sURL; +]wuJSxc  
sFilePath = sPath; q9*MNHg }  
sFileName = sName; <M+R\SH-  
this.nSplitter = nSpiltter; CboLH0Fa  
!!,0'c  
OSDy'@   
} grom\  
:1wrVU-?h  
;y>a nE}n{  
public String getSSiteURL() ql{_%x?  
{ L8$1K&!  
return sSiteURL; Ib`-pRU;  
} #bnb ': f  
b{Zpux+  
b$JBL_U5Ch  
public void setSSiteURL(String value) #5ax^p2*~  
{ On_@HQ/FI  
sSiteURL = value; B(5c9DI`  
} ]N)DS+V/  
ERMa# L  
kuMKX`_  
public String getSFilePath() 1 Y/$,Oa5  
{ \Sy7 "a  
return sFilePath; 0D&>Gyc*0  
} fw-\|fP  
^))RM_ic  
p<GR SJIk=  
public void setSFilePath(String value) !PUZWO  
{ OM83S|1s  
sFilePath = value; Fd$!wBL  
} !u|Tu4G^  
MmoR~~*  
t%VDRZo7  
public String getSFileName() ]`o!1(GA  
{ GHc/Zc"iX  
return sFileName; ?A*Kg;IU  
} Fwg^(;bL  
t'qL[r%?  
q0xjA  
public void setSFileName(String value) jA(vTR.`  
{ X]j)+DX>  
sFileName = value; hvV_xD8|  
} c-1q2y  
Xq#Y*lKVD  
|L3X_Me  
public int getNSplitter() x hs#u  
{ #KpY6M-H  
return nSplitter; eny/ fm  
} Ve 3 ;  
n(ir[w#,]"  
EMvHFu   
public void setNSplitter(int nCount) ,XKCz ]8V  
{ sH#X0fG  
nSplitter = nCount; _=f=fcl  
} epD?K  
} @tUoD>f  
#Z,E><t  
':h =*v8a  
/* Rd&9E  
**Utility.java kyYLP"oB=  
*/ +g*k*e>l  
package NetFox; ;@mRo`D`  
Sr Ca3PA  
_'0 @%P%  
public class Utility { X"asfA[6K  
},-*  
Tenf:Hm/k  
public Utility() q3e8#R)l  
{ ^z;JVrW  
Jl<ns,Zg  
lHfe<j]  
} i\?*=\a  
\1%l^dE@  
//线程睡眠 vv0Q$ O->  
public static void sleep(int nSecond) ,I.WX,OR  
{ ?,knit2x  
try{ e)^j+ l  
Thread.sleep(nSecond); }%!tT\8  
} F3U`ueP  
catch(Exception e) a|j%n  
{ 0S/' 94%w  
e.printStackTrace (); fRZ KEIyk  
} ^-)txC5{T  
} GRqT-/n"  
77 r(*.O|  
//日志 vG.9 H_&  
public static void log(String sMsg) PA;6$vqX  
{ {d3<W N  
System.err.println(sMsg); vXj<  
} Q+q,!w8  
63WS7s"  
L,[;k  
public static void log(int sMsg) k\r(=cex6  
{ ?knYY>Kzh1  
System.err.println(sMsg); /*)Tl   
} %D}H|*IPu  
} =^DLywAh}u  
_RkuBOv@e  
f2I6!_C!+  
/* myFAKRc  
**TestMethod.java v}JD2.O+  
*/ yzsab ^]  
package NetFox; K{fsn4rk  
&K+0xnUH  
]88];?KS}  
public class TestMethod { qPGuo5^  
xJ8%<RR!t  
kJ:F *34e=  
public TestMethod() U/{6% Qy  
{ ///xx/weblogic60b2_win.exe Zi\['2CG  
try{ W-~n|PX8+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U977#M Xf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >ezi3Zx^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5II(mSg8  
fileFetch.start();  Y k7-`  
} tB7}|jC  
catch(Exception e){e.printStackTrace ();} d(`AXyw  
'])2k@o@  
*LC+ PZV@  
} uGN^!NG-0  
XM1`x  
qO1tj'U<  
public static void main(String[] args) \00DqL(Oj`  
{ eJCjJ)  
new TestMethod(); 6vKS".4C  
} o]n!(f<(*  
} g| <wyt[  
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