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http断点续传简单实现(java)

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/* &b"PjtU.X  
**SiteFileFetch.java 8eWb{n uJ>  
*/ r[EN`AxDb  
package NetFox; ,i>5\Yl%  
import java.io.*; h8pc<t\6  
import java.net.*; V9B $_j4  
(a&.Ad0{  
&NHIX(b6  
public class SiteFileFetch extends Thread { KXicy_@DC`  
?y ]3kU  
_$i9Tk  
SiteInfoBean siteInfoBean = null; //文件信息Bean N@tzYD|hA  
long[] nStartPos; //开始位置 N{|N_}X`Y  
long[] nEndPos; //结束位置 dYf Vox;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \-V  
long nFileLength; //文件长度 m"H9C-Y  
boolean bFirst = true; //是否第一次取文件 s x`C<c~u  
boolean bStop = false; //停止标志 v,Ep2$  
File tmpFile; //文件下载的临时信息 7F)HAbIS  
DataOutputStream output; //输出到文件的输出流 3o"~_l$z  
BO/2kL8*  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) s7a\L=#p(  
public SiteFileFetch(SiteInfoBean bean) throws IOException Bk?MF6  
{ ',J3^h!b  
siteInfoBean = bean; DC[ -<:B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -2% [ ]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O23f\pm&  
if(tmpFile.exists ()) 6M612   
{ Bz /NFNi[p  
bFirst = false; W9a H]9b  
read_nPos(); }1X,~y]  
} Tvf]OJ9N  
else {U-VInu  
{ }v=q6C#Q>  
nStartPos = new long[bean.getNSplitter()]; 'T+3tGCy+  
nEndPos = new long[bean.getNSplitter()]; ;rd!kFd#bq  
} |}'}TYX0:  
W!GgtQw{F  
P`V#Wj4\  
o*5|W9  
} =0x[Sa$&,  
s&8QRI.  
N:"E%:wSbi  
public void run() "F)7!e  
{ Q:=s99  
//获得文件长度 RFQa9Rxk  
//分割文件 U/0NN>V  
//实例FileSplitterFetch j_p.KF'[?  
//启动FileSplitterFetch线程 Lrr6z05FQ  
//等待子线程返回 2 B5kpmH:  
try{ "qQU ^FW  
if(bFirst) f[h=>O  
{ @36^4E>h  
nFileLength = getFileSize(); PJh\U1Z  
if(nFileLength == -1) D@O '8  
{ #Cbn"iYee  
System.err.println("File Length is not known!"); ]O&TU X@)  
} @: %}clZ  
else if(nFileLength == -2) %# J8cB  
{ .+{nfmc,c  
System.err.println("File is not access!"); _%Mu{Ni&  
} -D{~7&  
else \=,+weGw@  
{ CF =#?+x  
for(int i=0;i<nStartPos.length;i++) .^P^lQT]>  
{ 4lvo9R  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y5PIR9-  
} Dzc 4J66  
for(int i=0;i<nEndPos.length-1;i++) !>9*$E |  
{ oBKZ$&_h  
nEndPos = nStartPos[i+1]; j!m~ :D  
} )p12SGR5  
nEndPos[nEndPos.length-1] = nFileLength; AvP*p{we  
} Y6^lKw  
} OXA_E/F  
_.Uz!2  
<Hm:#<\  
//启动子线程 P]r"E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "LXLUa03  
for(int i=0;i<nStartPos.length;i++) dpE\eXoa,  
{ >G/>:wwSP.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  /=[M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), V/>SjUNq  
nStartPos,nEndPos,i); YfF&: "-NU  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nGX~G^mZ  
fileSplitterFetch.start(); pN4!*7M  
} .F)--%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?R"5 .3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); UY%@i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", y%E R51+  
nEndPos = " + nFileLength); v`beql  
// fileSplitterFetch[nPos.length-1].start(); EB@!?=0x  
!dVcnK1  
W,AIE 6F  
//等待子线程结束 )-9|3`  
//int count = 0; z13"S(5D~  
//是否结束while循环 ] ^  
boolean breakWhile = false; zS?i@e $  
pklcRrx,a  
Ie4*#N_  
while(!bStop) f()^^+  
{ UPN2p&gM  
write_nPos(); ;CAB.aB~  
Utility.sleep(500); y7,~7f!N2  
breakWhile = true; t*.v!   
_;LHC;,:  
&\!-d%||)  
for(int i=0;i<nStartPos.length;i++) ;F~GKn;}  
{ WxO*{`T!  
if(!fileSplitterFetch.bDownOver) IFpmf0;^  
{ .fD k5uo  
breakWhile = false; mjs*Z{_F^  
break; &Lq @af#  
} QW6k!ms$  
} pR\etXeLd  
if(breakWhile) $I1p"6  
break; Hyee#fB  
(W@ ypK@  
b[RBp0]x  
//count++; `I m;@_J  
//if(count>4) "#e2"=3*  
// siteStop();  -U*XA  
} $V5Ol6@ 2  
cs@5K$v  
vO4 &ZQ>6  
System.err.println("文件下载结束!"); 06Uxd\E~  
} dWm[#,Q?  
catch(Exception e){e.printStackTrace ();} deu+ i  
} ZU "y<  
Y`( I};MO  
Jw {:1  
//获得文件长度 hj4A&`2  
public long getFileSize() K h% x  
{ ={feN L  
int nFileLength = -1; 09x\i/nb  
try{ aG=Y 6j G  
URL url = new URL(siteInfoBean.getSSiteURL()); (<%i8xu 2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <T0-m?D_$  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]7xAL7x  
_B W$?:)9  
}^LcKV  
int responseCode=httpConnection.getResponseCode(); fDbs3"H Q  
if(responseCode>=400) `yC R.3+  
{ *O 0*  
processErrorCode(responseCode); jj$'DZk  
return -2; //-2 represent access is error y?5*K  
} 6xBP72L;%"  
)n0g6  
{z.}u5N  
String sHeader; possM'vC  
XU SfOf(  
spe9^.SI  
for(int i=1;;i++) c~C :"g.y  
{ PfuYT_p4s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7rhpIP2n  
//Utility.log(in.readLine()); T-5T`awf  
sHeader=httpConnection.getHeaderFieldKey(i); h+$_:](PC  
if(sHeader!=null) H!45w;,I  
{ h_CeGl!M}  
if(sHeader.equals("Content-Length")) ".w*_1G7U  
{ |]m&LC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); nh E!Pk  
break; *dKA/.g  
} Tzk8y 7$[  
} -k<.Q=]<t  
else _<3:vyfdC  
break; Z;n}*^U  
} L>@6lhD)x  
} BtqJkdK!;1  
catch(IOException e){e.printStackTrace ();} ZE=~ re  
catch(Exception e){e.printStackTrace ();} 4&$G;?#W2  
)8Q|y  
2nEj X\BY  
Utility.log(nFileLength); awC&xVf  
]gmf%g'C  
H%sQVE7m  
return nFileLength; 3cfkJ|fuwe  
} y'zEaL&SI@  
iT|+<h  
M>v M@j  
//保存下载信息(文件指针位置) 3PJ  
private void write_nPos() AN.`tv  
{ }7C{:H2d  
try{ VKs$J)6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >2v_fw  
output.writeInt(nStartPos.length); | z('yy$  
for(int i=0;i<nStartPos.length;i++) L4[ bm[x  
{ <~Y4JMr"  
// output.writeLong(nPos); E|5gKp-wJ  
output.writeLong(fileSplitterFetch.nStartPos); <4! w2vxG  
output.writeLong(fileSplitterFetch.nEndPos); Y@r#:BH )  
} TvQAy/Y0  
output.close(); i;\i4MT  
} f|q6<n_nM  
catch(IOException e){e.printStackTrace ();} wZOO#&X#r  
catch(Exception e){e.printStackTrace ();} !IGVN:E  
} *v 8 ]99N  
{?j|]j  
|RpC0I  
//读取保存的下载信息(文件指针位置) "`3H0il;<  
private void read_nPos() \XpPb{:>  
{ ZRX>SyM  
try{ @L~y%#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jV7q)\uu^  
int nCount = input.readInt(); <&x_e-;b'  
nStartPos = new long[nCount]; >"Hj=?  
nEndPos = new long[nCount]; F^a D!O ~  
for(int i=0;i<nStartPos.length;i++) @*_K#3  
{ 3'']q3H  
nStartPos = input.readLong(); (Ux%7H_d  
nEndPos = input.readLong(); da-3hM!u+  
} ^Krkf4fO  
input.close(); "~+K`*0r8  
} X0U6:  
catch(IOException e){e.printStackTrace ();} M P3E]T~:  
catch(Exception e){e.printStackTrace ();} d>aZpJ[.  
} nY*ODL  
4+W}TKw  
=djzE`)0  
private void processErrorCode(int nErrorCode) `n%~#TJ  
{ =-:o?&64  
System.err.println("Error Code : " + nErrorCode); jAJkCCG  
} -I|yi'  
]>AW  
)0%<ZVB  
//停止文件下载 -S|L+">=Z  
public void siteStop()  t]vz+VQ  
{ $@U`zy"Y  
bStop = true; .:;i*  
for(int i=0;i<nStartPos.length;i++) 2?"9NQvz  
fileSplitterFetch.splitterStop(); 2 Sr'B;`p  
,sc>~B@Q  
$6J5yE  
} xp39TiXJ*  
} kO5KZ;+N-  
//负责部分文件的抓取 b"zq3$6*  
**FileSplitterFetch.java :N[2*.c[  
*/ =X1$K_cN  
package NetFox; Zkz:h7GUG-  
95+}NJ;r  
;w+A38N$J  
import java.io.*; ,wFLOfV@  
import java.net.*; : ._O.O  
0\mM^+fO  
~pw_*AN  
public class FileSplitterFetch extends Thread { ())|x[>JS+  
\ 0CGS  
VJNPs6  
String sURL; //File URL ^]v}AEcmW  
long nStartPos; //File Snippet Start Position HL)1{[|`  
long nEndPos; //File Snippet End Position ZWr\v!4  
int nThreadID; //Thread's ID :2?'mKa7  
boolean bDownOver = false; //Downing is over `  ^6}Dn  
boolean bStop = false; //Stop identical 6^wiEnA  
FileAccessI fileAccessI = null; //File Access interface w|M?t{  
CshME\/  
us~cIGm  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y3~z#<  
{ ^n<YO=|u  
this.sURL = sURL; T n/Zs|  
this.nStartPos = nStart;  oJ*,a  
this.nEndPos = nEnd; -BI!ZsC'  
nThreadID = id; ]\ !ka/%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ybsw{[X>M  
} =H8FV09x}  
iZiT/#,H2  
jIr\.i  
public void run() ||*F. p  
{ -0 <vmU  
while(nStartPos < nEndPos && !bStop) ZO/Jf Jn~  
{ 7FPSBvU#/  
^'`(E_2u  
$0K@= 7ms  
try{ ?wlRHVZ  
URL url = new URL(sURL); AZ4?N.X?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W|Sab$h  
httpConnection.setRequestProperty("User-Agent","NetFox"); _EP]|DTfr  
String sProperty = "bytes="+nStartPos+"-"; 0;T7fKj  
httpConnection.setRequestProperty("RANGE",sProperty); Zzg zeT+bv  
Utility.log(sProperty); Cw(ypu  
qD\9h`a  
a%U#PF6   
InputStream input = httpConnection.getInputStream(); OomC%9/=,  
//logResponseHead(httpConnection); :<B_V<  
I<sUB4T>#W  
\b $pH  
byte[] b = new byte[1024]; ](Wa:U}Xs  
int nRead; Hcg7u7M{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #_S]\=N(  
{ $\vNST E  
nStartPos += fileAccessI.write(b,0,nRead); Ns1n|^9  
//if(nThreadID == 1) HyWR&0J  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $V`1<>4  
} ,G46i)E\  
-Z:x!M[Xr  
x=xo9wEg  
Utility.log("Thread " + nThreadID + " is over!"); R= mT J'y  
bDownOver = true; F1_,V?  
//nPos = fileAccessI.write (b,0,nRead); { V(~  
} KWjhkRK4]  
catch(Exception e){e.printStackTrace ();} Spx%`O<  
} 7- LjBlH  
} ko[d axUB  
'6){~ee S  
)V>OND  
//打印回应的头信息 HH7WMYoKY  
public void logResponseHead(HttpURLConnection con) :vEfJSA 1<  
{ o[ks-C>jw  
for(int i=1;;i++) +FadOx7X$  
{ 'v0rnIsI?  
String header=con.getHeaderFieldKey(i); tF-l=ph}`  
if(header!=null) pGR3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); C@:X9NU  
Utility.log(header+" : "+con.getHeaderField(header)); Ad-5Zn c5  
else O%>*=h`P  
break; r0[<[jEh  
} 9)S3{i6w  
} x"C7NW[$  
.),9q z`  
'/ \*l<  
public void splitterStop() l1<=3+d  
{ ,:J[|9  
bStop = true; #W8?E_iu  
} N;-%:nC  
3w |5%`  
1QD49)  
} $)KODI>|  
XY? Cl  
~4FzA,,  
/* FCwE/ 2,  
**FileAccess.java -eh .Tk  
*//文件访问(定位,写) 6A.%)whI;  
package NetFox; )i:*r8*~  
import java.io.*; (X\]!'A  
F Xr\  
O"o|8 l}M/  
public class FileAccessI implements Serializable{ OS<GAA0  
Z]DZ:dF  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 wY%t# [T3  
RandomAccessFile oSavedFile; m6K7D([f  
long nPos; 3`{ vx  
R(&3})VOa  
xgkCN$zQ`  
public FileAccessI() throws IOException iQ2}*:Jc$  
{ 0$-|Th:o  
this("",0); oO3 ^9?Z  
} c*zeO@AAn  
2TB'HNTFx  
kjsj~jwvv  
public FileAccessI(String sName,long nPos) throws IOException 7_jt =sr  
{ `5Z'8^  
oSavedFile = new RandomAccessFile(sName,"rw"); <=6F=u3PtU  
this.nPos = nPos; wVI_SQ<8V  
oSavedFile.seek(nPos); c C) <Y#1  
} 8|\ -(:v  
V6c8o2G;+  
#tsP  
public synchronized int write(byte[] b,int nStart,int nLen) r|uR!=*|?  
{ [hot,\+f  
int n = -1; >)*d/^  
try{ {%k[Z9*tO  
oSavedFile.write(b,nStart,nLen); #l-zY}&  
n = nLen; 9$9a BW  
} [hH>BEtm  
catch(IOException e) Y?K?*`Pkc1  
{ ALO/{:l(  
e.printStackTrace (); 5$> buYF  
} rc>}3?o  
SCMvq?9  
o2$A2L9P  
return n; wi.E$R ckD  
} u-jc8W`Zd  
l]t^MEoc8  
Yg&/^  
} ^e_uprZWm  
aA>!p{/x  
kt_O=  
/* ]xb2W~  
**SiteInfoBean.java Ywt9^M|z;  
*/ "B"ql-K  
package NetFox; XJl 3\*  
[GK## z'5  
z$g__q-  
public class SiteInfoBean { fn7?g  
Wq1OYZ,  
ei1;@k/  
private String sSiteURL; //Site's URL x+'Ea.^  
private String sFilePath; //Saved File's Path wM;=^br  
private String sFileName; //Saved File's Name `RURC"  
private int nSplitter; //Count of Splited Downloading File {H9g&pfv  
>XuPg(Ow  
j3+ hsA/(k  
public SiteInfoBean() ~SA>$  
{//nSplitter的缺省值为5 2t?>0)*m  
//default value of nSplitter is 5 =)iAU/*N  
this("","","",5); #\xy,C'Y  
} B 'd@ms  
U F89gG4  
,}>b\(Lk  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7N vRZ!  
{ ?wIEXKI  
sSiteURL= sURL; QJx<1#  
sFilePath = sPath; # X{lV]Z  
sFileName = sName; (otD4VR_  
this.nSplitter = nSpiltter; [{`&a#Q  
c5Kc iTD^  
nS.qK/.s  
} -J]N &[  
Pum&\.l  
2Mw`  
public String getSSiteURL() CA$|3m9)NM  
{ v`7~#Avhz  
return sSiteURL; PCc{0Rp\vk  
} =XSupM[T  
#&K}w 0}k  
k%N$eO$  
public void setSSiteURL(String value) ?4W6TSW-'  
{ ):L0{W{  
sSiteURL = value; K\lu;   
} i~4$V  
!\Xrl) $j{  
dg(sRTi{  
public String getSFilePath() 6mIRa(6V  
{ uSxldc  
return sFilePath; uXG$YDKqC  
} 7< ?Aou  
mGw*6kOIS  
/}d)g4\j  
public void setSFilePath(String value) d=g,s[FMm  
{ m^tf=O<  
sFilePath = value; h?->A#  
} ,C'mE''x  
G/1V4-@  
vsB3n$2@u  
public String getSFileName()  SmAF+d  
{ .SWn/Kk  
return sFileName; B/JMH 1r  
} 9}G<\y  
]4 \6_J&  
O%} hNTS"  
public void setSFileName(String value) E@Yq2FBpnn  
{ R:44Gv7  
sFileName = value; M^/ZpKeT"  
} 0A75)T=lQ  
J$yJ2G  
"haJwV6-  
public int getNSplitter() lt0byn$vz  
{ GM0pHmC  
return nSplitter; x^YsXzu  
} XpT~]q}  
,@8*c0Y~<!  
'FG@Rg (  
public void setNSplitter(int nCount) bI)%g  
{ ~ =$d>ZNQ  
nSplitter = nCount; <;!#+|L/  
} 9_%??@^>  
} 5^{).fig  
hx}X=7w  
RJD(c#r$  
/* DC'L-]#<  
**Utility.java 2)|G%f_lS  
*/ o-<.8Z}>at  
package NetFox; ,GF(pCZzG  
mqQC`Aqx:  
.JWN\\  
public class Utility { {jEEAH)  
FBA th !E  
 :LTjV"f  
public Utility() &^F'ME  
{ Ap<j;s4`  
1Zgv+.  
D.x&N~-  
} {$_Gjv  
])Z p|?Y  
//线程睡眠 WWVQJ{,}  
public static void sleep(int nSecond) VO7&<Y}{x  
{ ?#/~ BZR!  
try{ slG%o5|m  
Thread.sleep(nSecond); T $o;PJc  
} a)rT3gl  
catch(Exception e) zQsW*)L  
{ -b'/}zz  
e.printStackTrace (); #7naI*O  
} u 236a\:  
} F<Z13]|  
&MJ`rj[%  
//日志 q.d qr<  
public static void log(String sMsg) ?l ](RI  
{ :}Z Y*ind  
System.err.println(sMsg); /k=k rAz.  
} X;yThb` iI  
g"X!&$ &  
-;&-b>b  
public static void log(int sMsg) md /NMC \  
{ )*9,H|2nS  
System.err.println(sMsg); Ihx[S!:  
} E5t /-4  
} (*V:{_r  
t^g+nguz  
(6X{ &  
/* o(oD8Ni  
**TestMethod.java @BI;H V%k  
*/ G5!!^p~  
package NetFox; @6{F4  
m/ngPeZ  
HXQ } B$V  
public class TestMethod { wo\O 0?d3{  
a- 7RJ.  
[&:dPd1_  
public TestMethod() F|?}r3{aJ  
{ ///xx/weblogic60b2_win.exe .}iRe}=  
try{ ZtX \E+mC  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]nm(V  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;! #IRR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9K=K,6 b  
fileFetch.start(); ?fNUmk^A<  
} /=:F w}vt  
catch(Exception e){e.printStackTrace ();} |pR'#M4j4A  
\N)!]jq  
zTfl#%  
} 4\14HcTcK  
FQ]5W |e  
%=i/MFGX  
public static void main(String[] args) OTmr-l6  
{ Kj#h9e  
new TestMethod(); yUg'^SEbLk  
} )wk9(|[o  
} -z>m]YDH  
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