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http断点续传简单实现(java)

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/* ni2H~{]z  
**SiteFileFetch.java ^z[s;:-  
*/ T?AGQcG  
package NetFox; .8b 4  
import java.io.*; P2`ks[u+i  
import java.net.*;  %ef+Z  
YLSG 5vF+  
3qpk Mu3  
public class SiteFileFetch extends Thread { _JR4 PKtx  
hZ2PP ^  
7Mo O2  
SiteInfoBean siteInfoBean = null; //文件信息Bean +QldZba  
long[] nStartPos; //开始位置 PDD` eK}Fj  
long[] nEndPos; //结束位置 :\4O9f*5+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 })mez[UmZ  
long nFileLength; //文件长度 U}gYZi;;$  
boolean bFirst = true; //是否第一次取文件 /jj@ =H  
boolean bStop = false; //停止标志 U-WrZ|-  
File tmpFile; //文件下载的临时信息 \R79^  
DataOutputStream output; //输出到文件的输出流 yt!K|g  
Z#V[N9L  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) A8Jbl^7E+  
public SiteFileFetch(SiteInfoBean bean) throws IOException -F8%U:2a  
{ 3g-}k  
siteInfoBean = bean; J,7_5V@jJ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a#uJzYB0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1"v;w!uh  
if(tmpFile.exists ()) 1d\K{ 7i#  
{ *,'"\n  
bFirst = false; t8?+yG;  
read_nPos(); N"E\o,_  
} ioa 1n=j  
else i w m7M  
{ P]6pPS  
nStartPos = new long[bean.getNSplitter()]; c$e~O-OVD?  
nEndPos = new long[bean.getNSplitter()]; =WO{h48]  
} \s~ W;m  
3J(STIxg  
zcxG%? Q  
OVj,qL)  
} 8De `.!Gg  
o,aI<5"  
e;!<3b  
public void run() NoKYHN^*w  
{ @kqy!5)K  
//获得文件长度 =A!I-@]q<  
//分割文件 57[O)5u.+  
//实例FileSplitterFetch .Bi7~*N  
//启动FileSplitterFetch线程 m|f|u3'z$  
//等待子线程返回 (>;~((2  
try{ \H" (*["&  
if(bFirst) IL>g-  
{ UI!EIZ*~  
nFileLength = getFileSize(); G53!wIW2:  
if(nFileLength == -1) NEGpf[$  
{ pn =S%Qf]  
System.err.println("File Length is not known!"); pAa{,,Qc  
} ait/|a  
else if(nFileLength == -2) QkF-}P%  
{ eGguq~s`  
System.err.println("File is not access!"); E* lqCh  
} @l;f';+  
else /1OhW>W3eH  
{ c69C=WQ  
for(int i=0;i<nStartPos.length;i++) UyF]gO  
{ ]\_4r)cN<n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .0a$E`V=D  
} #a .aD+d'  
for(int i=0;i<nEndPos.length-1;i++) #vDe/o+=  
{ a(J~:wgd  
nEndPos = nStartPos[i+1]; oa9T3gQ?  
} \7/xb{z|  
nEndPos[nEndPos.length-1] = nFileLength; DAvAozM  
} .d8~]@U!<  
} }RyYzm2  
sF<4uy  
](a<b@p  
//启动子线程 I`y}Ky<q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; FijzO  
for(int i=0;i<nStartPos.length;i++) -AffKo  
{ XDI@ mQmzB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FvvF4 ,e5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `Zk?.1*2/  
nStartPos,nEndPos,i); c^=,@#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Pd@?(WQ  
fileSplitterFetch.start(); ^$T>3@rDB  
} 1= <Qnmw  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9^aMmN&6N2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :_?>3c}L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", GJ((eAS)  
nEndPos = " + nFileLength); +Uk/Zg w^  
// fileSplitterFetch[nPos.length-1].start(); "urQUpF  
tZ6KU11O  
H~$a6T"&  
//等待子线程结束 XGO_n{ x  
//int count = 0; w>!KUT  
//是否结束while循环 .IYE"0)wJ  
boolean breakWhile = false; :|fzGf  
QzV:^!0J  
|9(uiWf  
while(!bStop) 4W1"=VL[g  
{ Tlf G"HzZ%  
write_nPos(); W{0<ro`  
Utility.sleep(500); p oNQ<ijK  
breakWhile = true; l$zM|Z1wR`  
PVU(R J  
g@S"!9[;U  
for(int i=0;i<nStartPos.length;i++) G_X'd  
{ hx:x5L>  
if(!fileSplitterFetch.bDownOver) ^c-1w V` /  
{ K\;b3  
breakWhile = false; IJs` 3?  
break; 0_%u(?  
} BGUP-_&  
} Dpof~o,f  
if(breakWhile) T"dEa-O  
break; paiF ah  
km8[azB o  
+='.uc_  
//count++; j[c|np4k\  
//if(count>4) SFh6'v'1N@  
// siteStop(); Z,Q)\W<'-  
} R[Pyrs!H  
q,+d\-+  
Mb+cXdZb  
System.err.println("文件下载结束!"); Blf;_e~=[j  
} ^Dd$8$?[  
catch(Exception e){e.printStackTrace ();} mF#{"  
} ~xzRx$vU  
6{1c S  
<G#JPt6  
//获得文件长度 eyUo67'7  
public long getFileSize() N|8TE7- F|  
{ jtN2%w;  
int nFileLength = -1; 4GaF:/  
try{ `F(KM '  
URL url = new URL(siteInfoBean.getSSiteURL()); s_VP(Fe@K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e >MC 3D`5  
httpConnection.setRequestProperty("User-Agent","NetFox"); rbs:qLa%  
h*&-[nSo  
DmPp&  
int responseCode=httpConnection.getResponseCode(); K~C*4H:9  
if(responseCode>=400) dRt]9gIsx  
{ }cMb0`oA  
processErrorCode(responseCode); Rl-Sr  
return -2; //-2 represent access is error /1g_Uv;  
} ,LU/xI0O  
RXLD5$s^  
NCd_h<}|6F  
String sHeader; mVW:]|!s  
%5a>@K]  
K^w(WE;db  
for(int i=1;;i++) YW0UIO  
{ |WlWZ8]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^qYJx  
//Utility.log(in.readLine()); !SEg4z  
sHeader=httpConnection.getHeaderFieldKey(i); k6. }.  
if(sHeader!=null) pT.iQ J|  
{ gHA"O@HgDI  
if(sHeader.equals("Content-Length")) "ifYy>d  
{ @)|62Dv /  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |%we@ E  
break; r#3(;N{=  
} =K}5 fe  
} \h?C G_|]  
else yw$er?  
break; }M * Oo  
} &+d>xy\^/  
} ojUBa/  
catch(IOException e){e.printStackTrace ();} j:\MrYt0H  
catch(Exception e){e.printStackTrace ();} i\2~yXw\  
Z6A*9m  
"\)j=MI8u+  
Utility.log(nFileLength); &8z`]mB{t  
n<uF9N<   
4tof[n3us  
return nFileLength; z45ImItH  
} q:+,'&<D  
$62!R]C9\  
O}"VK  
//保存下载信息(文件指针位置) pQ!NhzQ  
private void write_nPos() [n44;  
{ M)#aX|%Mh  
try{ -]\UFR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); v:nm#P%P  
output.writeInt(nStartPos.length); ^ ,d!K2`  
for(int i=0;i<nStartPos.length;i++) 8:|F'{<<b  
{ #\_N-bVu  
// output.writeLong(nPos); a4Fe MCvV9  
output.writeLong(fileSplitterFetch.nStartPos); S{7A3 x'B  
output.writeLong(fileSplitterFetch.nEndPos); k$j>_U? P  
} HSE9-c =  
output.close(); {+F/lN@  
} bM; ==W  
catch(IOException e){e.printStackTrace ();} -uHD| }  
catch(Exception e){e.printStackTrace ();} @~qlSU&  
} n&jfJgD&g  
*?VbN}g2  
DKx8<yEky  
//读取保存的下载信息(文件指针位置) py6|uGN  
private void read_nPos() =rMT1  
{ nm_]2z O  
try{ $0~H~ -  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); s=h  
int nCount = input.readInt(); ?4P*,c  
nStartPos = new long[nCount]; ryg1o=1v/  
nEndPos = new long[nCount]; bx_`S#*N  
for(int i=0;i<nStartPos.length;i++) z:{'IY  
{ waz)jEk  
nStartPos = input.readLong(); Zui2O-L?V  
nEndPos = input.readLong(); w$MFCJ:p&  
} NTkGLD1e.  
input.close(); 4p\<b8(9>  
} oJA%t-&%R  
catch(IOException e){e.printStackTrace ();} PbvRh~n  
catch(Exception e){e.printStackTrace ();} iC10|0%{  
} ~Pq1@N>n  
FctqE/>}I  
oi^2Pvauh  
private void processErrorCode(int nErrorCode) 33z)F  
{ wC+_S*M-K  
System.err.println("Error Code : " + nErrorCode); $6kVhE!;  
} $vlq]6V8  
BT.;l I  
 \09eH[  
//停止文件下载 _~ZNX+4  
public void siteStop() rXPq'k'h#-  
{ w7 @fiH{  
bStop = true; 3(0k!o0 "  
for(int i=0;i<nStartPos.length;i++) ze@NqCF  
fileSplitterFetch.splitterStop(); (A|Gb2X  
@KfFt R-;  
D~E1hr&Vd>  
} a|Io)Qhr  
} eK PxSN Z  
//负责部分文件的抓取 h,o/(GNnW  
**FileSplitterFetch.java j6]+ fo&3  
*/ +P:xB0Tm D  
package NetFox; YBqu7&  
uLX5khQ  
l=,\ h&  
import java.io.*; e33j&:O  
import java.net.*; >qk[/\^O  
#Mkwd5S|L  
,:Qy%k}f  
public class FileSplitterFetch extends Thread { Fa:fBs{  
h U\)CM  
{>PN}fk2QP  
String sURL; //File URL 6A&e2K>A  
long nStartPos; //File Snippet Start Position KJ M :-z@  
long nEndPos; //File Snippet End Position ufyqfID  
int nThreadID; //Thread's ID Dvbrpn!sk  
boolean bDownOver = false; //Downing is over q1}HsTnBH  
boolean bStop = false; //Stop identical g`I`q3EF)  
FileAccessI fileAccessI = null; //File Access interface  yV[9 (  
"Ah (EZAR  
l$N b1&  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #-*7<wN   
{ sLrSi  
this.sURL = sURL; Z M_ 6A1  
this.nStartPos = nStart; ywWF+kR_  
this.nEndPos = nEnd; RZ 4xR  
nThreadID = id; {G$I|<MD2T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 zO8`xrN!  
} K(@QKRZ7[  
g S xK9P  
d*Q:[RUf,  
public void run() itClCEOA  
{ (WZKqt)S"o  
while(nStartPos < nEndPos && !bStop) 0goKiPx  
{ "h?;)Ye  
RP 'VEJ   
:ZG^`H/X1d  
try{ 6$c,#%Jt*  
URL url = new URL(sURL); 7ADh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e&%m[:W:<  
httpConnection.setRequestProperty("User-Agent","NetFox"); `2`Nu:r^  
String sProperty = "bytes="+nStartPos+"-"; WwG +Xa  
httpConnection.setRequestProperty("RANGE",sProperty); jR-DH]@y  
Utility.log(sProperty); &S[tI$  
o_; pEe  
J%}9"Q5  
InputStream input = httpConnection.getInputStream(); g-lF{Z  
//logResponseHead(httpConnection); 5y-8_)y8o  
AKs=2N> 7  
."b=dkx  
byte[] b = new byte[1024]; $Lg% CY  
int nRead; %{qJkjG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dayp1%d  
{ 6Q S[mWU  
nStartPos += fileAccessI.write(b,0,nRead); m| 8%%E}d  
//if(nThreadID == 1) $Gt1T[:QUX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D>"U0*h  
} }%LwaRT  
`~|8eKFq!  
pgT XyAP{  
Utility.log("Thread " + nThreadID + " is over!"); . +_IpygQ  
bDownOver = true; G tI]6t  
//nPos = fileAccessI.write (b,0,nRead); j$r.&,m  
} B198_T!  
catch(Exception e){e.printStackTrace ();} +bK[3KG4F5  
} f5D.wSY  
} KY'"Mg^!  
18JhC*in  
0_b7*\xc  
//打印回应的头信息 ;4. D%  
public void logResponseHead(HttpURLConnection con) <K4`GT"n  
{ rx`G* k{X  
for(int i=1;;i++) L-ans2?  
{ K8E:8`_cx  
String header=con.getHeaderFieldKey(i); ~@ a7RiE@  
if(header!=null) @?ntMh6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); E-h`lDoJ  
Utility.log(header+" : "+con.getHeaderField(header)); VesW7m*z  
else 2y; |6`  
break; o %#Z  
} K0B J  
} N}{CL(xi  
/E>z8 J$  
,Nl]rmI  
public void splitterStop() aIaydu+\  
{ !R,9Pg*Ey  
bStop = true; J]uYXsC  
} 9D74/3b*  
^aVoH/q*C  
'G z>X :  
} %-"?  
<}'hkEh{d=  
pKK&+umg  
/* 3$f%{~3  
**FileAccess.java INwc@XB  
*//文件访问(定位,写) cyUNJw  
package NetFox; $4.mRS97g  
import java.io.*; 4eb<SNi  
JtYc'%OF  
EFeGxM  
public class FileAccessI implements Serializable{ !NuYx9L?L  
-x )(2|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pGw|T~e%  
RandomAccessFile oSavedFile; TnET1$@qr*  
long nPos; YLk; ^?  
Mi'Q5m  
lh`inAt)"  
public FileAccessI() throws IOException A(AyLxB47*  
{ n0:+D R  
this("",0); Zrfp4SlZZ  
} $ hB;r  
2 =tPxO')B  
Cnf;5/  
public FileAccessI(String sName,long nPos) throws IOException 2D-ogSIo  
{ qg#WDx /  
oSavedFile = new RandomAccessFile(sName,"rw"); Bv"Fx* {W  
this.nPos = nPos; WH :+HNl1d  
oSavedFile.seek(nPos); L;.6j*E*  
} 'qLk"   
j9C=m"O  
5n;|K]UW  
public synchronized int write(byte[] b,int nStart,int nLen) Avw"[~Xd  
{ 9[5NnRv$P  
int n = -1; 2YK4 SL  
try{ n`f},.NM|  
oSavedFile.write(b,nStart,nLen); s%]-Sw9  
n = nLen; z.23i^Q  
} }|f\'S   
catch(IOException e) $I_ 04k#t  
{ ]!H*oP8a*  
e.printStackTrace (); >VP\@xt(R[  
} #V-qS/ q"  
9,5v%HZ  
ri~dWx  
return n; wbI(o4rXE  
} Y%qhgzz?/  
sBp|Lo  
pfg"6P  
} _J&u{  
rPK?p J  
GN{\ccej  
/* )<4o"R:*  
**SiteInfoBean.java W"Dj+/uS  
*/ 9.e?<u*-z  
package NetFox; n]4)~ZIAU  
Rz`<E97-  
93fKv  
public class SiteInfoBean { `u:U{m  
#c4LdZu9  
;3\F b3d  
private String sSiteURL; //Site's URL Szi4M&!K  
private String sFilePath; //Saved File's Path (d993~|h  
private String sFileName; //Saved File's Name tZ>>aiI3  
private int nSplitter; //Count of Splited Downloading File u]E%R&  
@&+h3dV.V  
?t)y/@eG  
public SiteInfoBean() 7|zt'.56[  
{//nSplitter的缺省值为5 `]]gD EPG{  
//default value of nSplitter is 5 ]Vjn7P`~ N  
this("","","",5); #f.@XIt'  
} nL^6{I~  
f&`v-kiAn=  
)Tngtt D  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  9 N=KU  
{ [gzU / :  
sSiteURL= sURL; UE7 P =B  
sFilePath = sPath; D]y6*Ha  
sFileName = sName; } 3:TPW5S  
this.nSplitter = nSpiltter; psRm*,*O  
y5a^xRDw  
EN.yU!N.4  
} lGG1d  
w,8 M  
] >ipC,v  
public String getSSiteURL() sLbz@54  
{ toTAWT D  
return sSiteURL; /dOQ4VA\  
} =i%2/kdi0b  
PyYKeo=  
0x^$q? \A  
public void setSSiteURL(String value) pY=?r{@  
{ spO?5#  
sSiteURL = value; o~P8=1t   
} b{s E#m%r  
1:YDN.*  
s>~&: GUwR  
public String getSFilePath() i04Sf^  
{ Si]Z`_  
return sFilePath; 4)Pt]#Ti  
} 8SAz,m!W)  
q*{"6"4(  
UMhM8m!=o  
public void setSFilePath(String value) w?M*n<) O  
{ +\Q6Onqr  
sFilePath = value; .E;6Xx_+r  
} od^ha  
jn}6yXB  
}r^MXv~(  
public String getSFileName() I]SR.Yp%  
{  vA`[#(C  
return sFileName; 5 @[%P=  
} }sJ% InL  
0 SKt8pL`  
;t?pyFT2Z  
public void setSFileName(String value) Ur&: Rr  
{ 8QC:ro  
sFileName = value; iT^lk'?{O  
} P#ru-0DD  
-m'a%aog  
?U-p jjM  
public int getNSplitter() w4L\@y 3  
{ ^;@Bz~Z  
return nSplitter; '3hvR4P  
} ^* DKF  
H8\{ GGg  
u]dpA  
public void setNSplitter(int nCount) Ds}6{']K  
{ A5H[g`&  
nSplitter = nCount; RuRJjcnY  
} N,[M8n,  
} ?J6hiQvL  
:He:Bdk  
/=r&9P@Ay<  
/* \17)=W  
**Utility.java n.1a1Tf  
*/  &R^mpV5  
package NetFox; _R-#I  
HKxrBQr78  
LoCxoAg  
public class Utility { "R9kF-  
H`io|~Q  
fZ %ZV  
public Utility() {?L}qV  
{ JK_$A;Q  
&P+cTN9)  
4P:vo$Cy  
} Sr+1.77}  
R>0ta  Q  
//线程睡眠 ?1412Tq5  
public static void sleep(int nSecond) +M.|D,wg2  
{ rW6w1  
try{ *v5y]E%aW  
Thread.sleep(nSecond); a9qZI  
} g)p[A 4  
catch(Exception e) %##9.Xm6l  
{ cxv) LOl-  
e.printStackTrace (); Hd2_Cg FB  
} s~63JDy"E  
} 5rcno.~QO  
(6A{6_p  
//日志 rpXw 8  
public static void log(String sMsg) rvfl~<G*  
{ Z'j<wRf  
System.err.println(sMsg); *l9Y]hinq  
} d*AV(g#B  
1)Ag|4  
q;AQ6k(  
public static void log(int sMsg) ?41| e+p  
{ >qgBu_  
System.err.println(sMsg); )eG&"3kFe!  
} oDP|>yXC)  
} }`g*pp*  
Anm5Cvt;i  
^IId =V=2  
/* 3&*%>)  
**TestMethod.java Rd!.8K[  
*/ n&Tv]-  
package NetFox; .ev]tu2N  
[{c8:)ar  
[a Z)*L ;  
public class TestMethod { M1>a,va8Zq  
"bO]  
vaU7tJ:  
public TestMethod() +I~?8*  
{ ///xx/weblogic60b2_win.exe rLXn35O  
try{ u}h'v&"e,  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); aOuon0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); W>Kwl*Cis"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *>#cs#)  
fileFetch.start(); x$p\ocA  
} J+4uUf/d!  
catch(Exception e){e.printStackTrace ();} Q:LuRE!t  
Umd!j,  
S:j0&*  
} *Xo f;)Z^  
";xEuX  
A y`a>:p  
public static void main(String[] args) <w A_2S Y  
{ d^Wh-U  
new TestMethod(); bpILiC  
} N?Z?g_a8  
} !6%mt}h  
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