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http断点续传简单实现(java)

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/* TF?~vS%@P  
**SiteFileFetch.java uhU'm@JZ  
*/ Gc_KS'K@$  
package NetFox; Oe21noL  
import java.io.*; aUi^7;R&<  
import java.net.*; >c$3@$  
T>|Y_3YO_a  
SmUiH9qNd,  
public class SiteFileFetch extends Thread { a1shP};pK  
tB`IBuy9!"  
xYY^tZIV  
SiteInfoBean siteInfoBean = null; //文件信息Bean >*EJ6FPO  
long[] nStartPos; //开始位置 @<yYMo7  
long[] nEndPos; //结束位置 P8[k1"c!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #~4;yY\$I  
long nFileLength; //文件长度 B r6tgoA  
boolean bFirst = true; //是否第一次取文件  i (`Q{l  
boolean bStop = false; //停止标志 y!T8(  
File tmpFile; //文件下载的临时信息 X/ Ii}X/p  
DataOutputStream output; //输出到文件的输出流 '$[a-)4  
g"N&*V2  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 6,!$S2(zT  
public SiteFileFetch(SiteInfoBean bean) throws IOException Js(MzL  
{ <Ira~N  
siteInfoBean = bean; 8Vy/n^3)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p^w_-( p  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); o(C;;C(*{  
if(tmpFile.exists ()) Z`#XB2,  
{ OVE?;x>n/1  
bFirst = false; !DD4Bqez  
read_nPos(); hW`o-'  
} \wR\i^  
else ]MC5 uKn  
{ kG5Uc8 3#G  
nStartPos = new long[bean.getNSplitter()]; EHfB9%O7y  
nEndPos = new long[bean.getNSplitter()]; BY':R-~(  
} gX| \O']6  
l5D4 ?`|  
6Ilj7m*  
u4'B  
} Tfx-h)oP3  
Ya-GDB;L  
R,fAl"wMu  
public void run() f ~bgZ  
{ +|H,N7a<  
//获得文件长度 !r9rTS]  
//分割文件 _w2KUvG-8  
//实例FileSplitterFetch R+2~%|{d  
//启动FileSplitterFetch线程 N36B*9m&p  
//等待子线程返回 ce*?crOV  
try{ a5&[O  
if(bFirst) EKS?3z%!  
{ b;nqhO[f}  
nFileLength = getFileSize(); +11 oVW  
if(nFileLength == -1) yZ]?-7  
{ wL}X~Xa3i  
System.err.println("File Length is not known!"); xe9\5Gb}  
} $ab{GxmX'4  
else if(nFileLength == -2) #V$sb1u  
{ u68ic1  
System.err.println("File is not access!"); ,1]VY/  
} =dmxE*C  
else V;Q@' <w  
{ DiZ;FHnaG?  
for(int i=0;i<nStartPos.length;i++) [^XD @  
{ >U?#'e{qW  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F%4N/e'L  
} D |fo:Xp,  
for(int i=0;i<nEndPos.length-1;i++) _ q AT%.  
{ 1#8~@CQ ::  
nEndPos = nStartPos[i+1]; >FJK$>[1:p  
} R]RLy#j  
nEndPos[nEndPos.length-1] = nFileLength; 9$}> O]  
} 02)Ybp6y  
} 'Mhnu2d  
54/ZGaonz  
-y[y.#o  
//启动子线程 |tz{Es<`B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !3o/c w9  
for(int i=0;i<nStartPos.length;i++) _@VKWU$$  
{ i8DYC=r  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hl*#iUq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n A%8 bZ+  
nStartPos,nEndPos,i); bjN"H`Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F=f9##Y?7M  
fileSplitterFetch.start(); wRq f'  
} 4VkJtu5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AgB$ w4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1F+nWc2b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Mko,((>I1  
nEndPos = " + nFileLength); f9hH{ ( A  
// fileSplitterFetch[nPos.length-1].start(); ^K 9jJS9K  
zm4e+v-  
,4}s 1J#  
//等待子线程结束 2P{! n#"  
//int count = 0; &ha<pj~  
//是否结束while循环 A5O;C  
boolean breakWhile = false; I;9DG8C&v*  
n@S|^cH  
%6Y}0>gY  
while(!bStop) e`)zR'As  
{ QqcAmp  
write_nPos(); >R.!Qze\G  
Utility.sleep(500); G B>T3l"  
breakWhile = true; N'|9rB2e  
/)rv Ndn  
U]ZI_[\'U  
for(int i=0;i<nStartPos.length;i++) t1G2A`  
{ =S\pI  
if(!fileSplitterFetch.bDownOver) y@Td]6|f  
{ : %U lNk  
breakWhile = false; P%<MQg|k`  
break; tcI Z 2H%  
} mk6>}z*  
} t,kai6UM  
if(breakWhile) 4hn' b[  
break; 'ztY>KVj  
g=Nde2d?  
G@<[fO|Iam  
//count++; t /lU*  
//if(count>4) Owh:(EJ"d  
// siteStop(); AO8%!+"_  
} V<d`.9*}  
ETfoL.d$(  
+V#dJ[,8;.  
System.err.println("文件下载结束!"); ,@Elw>^  
} 8=mx5Gwz-  
catch(Exception e){e.printStackTrace ();} xJFxrG'c  
} 6O'Y@9#  
X\BdN Hr  
qi8~bQ{rH  
//获得文件长度 (T",6xBSG  
public long getFileSize() kB-<17  
{ quFNPdP  
int nFileLength = -1; Q*/jQC  
try{ }/7rA)_  
URL url = new URL(siteInfoBean.getSSiteURL()); Angt=q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Wix4se1Ac  
httpConnection.setRequestProperty("User-Agent","NetFox"); ) =|8%IrB  
D]K?ntS[*  
r<"k /  
int responseCode=httpConnection.getResponseCode(); }]j#C  
if(responseCode>=400) Kq:vTz&<  
{ 8`q"] BQN  
processErrorCode(responseCode); Vv>hr+e  
return -2; //-2 represent access is error w5a;ts_x  
} [ _&z+  
<{.pYrn  
!:1BuiL  
String sHeader; r#^uY:T%  
~|`jIqU  
eak+8URo  
for(int i=1;;i++) {CGk9g" `  
{ {)- 3g~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4aG}ex-s|  
//Utility.log(in.readLine()); , L8(Vo`-  
sHeader=httpConnection.getHeaderFieldKey(i); gq)uv`3  
if(sHeader!=null) 7:OF>**  
{ p[D,.0SuC  
if(sHeader.equals("Content-Length")) iD:T KB_r  
{ ^~m}(6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +kOXa^K  
break; Q_|Lv&  
} #vT~D>zj  
} 3 n1 > +8  
else \B8[UZA.&  
break; [S[@ Q[zP@  
} CSMx]jbb  
} r7  *'s  
catch(IOException e){e.printStackTrace ();} HO39>:c  
catch(Exception e){e.printStackTrace ();} M}9PicI?7  
?/Z5%?6  
_MUSXB'  
Utility.log(nFileLength); $`Aps7A  
k)S'@>n{u  
O)}5`0@L  
return nFileLength; ?,*KAGg%  
} 9 H~OC8R:  
Ert` ]s~  
(e[8`C  
//保存下载信息(文件指针位置) /@K1"/fqH  
private void write_nPos() O@,9a~Ghd  
{ )dI  `yf  
try{ RMBPm*H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UQ+!P<>w   
output.writeInt(nStartPos.length); !a9/8U_>XF  
for(int i=0;i<nStartPos.length;i++) Uj> bWa`  
{ k!sk\~>YO  
// output.writeLong(nPos); -Sj|Y }  
output.writeLong(fileSplitterFetch.nStartPos); gJuA*^  
output.writeLong(fileSplitterFetch.nEndPos); LT) G"U~  
} ~ ^) 4*@i6  
output.close(); [xg& `x9,.  
} xX{gm'3UYa  
catch(IOException e){e.printStackTrace ();} dL>8|  
catch(Exception e){e.printStackTrace ();} ?h'd\.j{  
} UWq[K&vQZ  
#Ue_  
C(5B/W6  
//读取保存的下载信息(文件指针位置) dO\irv)  
private void read_nPos() ^EmI;ks  
{ Y` tB5P  
try{ f hr QJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); h$q=NTV  
int nCount = input.readInt(); L:RMZp*bK  
nStartPos = new long[nCount]; F<A[S "  
nEndPos = new long[nCount]; RJT=K{2x  
for(int i=0;i<nStartPos.length;i++) Ce_E S.  
{ ma(E}s  
nStartPos = input.readLong(); =aE!y5  
nEndPos = input.readLong(); ayoqitXD?  
} m8<l2O=m  
input.close(); YCEdt>5PA  
} G,JNUok  
catch(IOException e){e.printStackTrace ();} rP7f~"L  
catch(Exception e){e.printStackTrace ();} %oqC5O6  
} Dg2=;)"L  
u}I\!-EX!v  
q3-V_~5^/z  
private void processErrorCode(int nErrorCode) E]j2%}6Z%  
{ 8\@&~&(y:  
System.err.println("Error Code : " + nErrorCode); W: vw.  
} mu}T,+9\  
Q7@.WG5  
a}MSA/K(  
//停止文件下载 x7 l3&;yDv  
public void siteStop() |] 8Hh>  
{ 0413K_  
bStop = true; Pf?y!d K<  
for(int i=0;i<nStartPos.length;i++) ts3BmfR?  
fileSplitterFetch.splitterStop(); Auz.wes  
(r+#}z}  
fd} U l  
} }D>nXhO&  
} ^%pM$3ov  
//负责部分文件的抓取  ^q=D!g  
**FileSplitterFetch.java Ot#O];3  
*/ :;(zA_-  
package NetFox; '8b/TL  
'Bv)UfZ  
0kdPr:B Q0  
import java.io.*; | p"E0av  
import java.net.*; kxp, ZP  
Vx6/Rehj  
ni$S@0  
public class FileSplitterFetch extends Thread { qvH7otA  
Eu^? e  
%8a886;2  
String sURL; //File URL Rg!Fu  
long nStartPos; //File Snippet Start Position 3j iSvrfI  
long nEndPos; //File Snippet End Position q`8M9-~  
int nThreadID; //Thread's ID *>a+`|[1*  
boolean bDownOver = false; //Downing is over \Gk4J<  
boolean bStop = false; //Stop identical G$B( AWL  
FileAccessI fileAccessI = null; //File Access interface :"4Pr/}rT  
DcQ[zdEz+  
_z$lg]q  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "+6:vhP5  
{ 8 ;C_@  
this.sURL = sURL; feH|sz`e  
this.nStartPos = nStart; 3 0fsVwE2  
this.nEndPos = nEnd; l12_&o"C~  
nThreadID = id; {T0f]]}Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 z"@yE*6  
} }  :@s  
g{}{gBplnl  
:bhpYEUMx  
public void run() ` 5.PPI\h2  
{ JQhw>H9&  
while(nStartPos < nEndPos && !bStop) `T gwa  
{ Vg0$5@  
vIi#M0@N  
mrzrQ@sN  
try{ \[Dxg`;4  
URL url = new URL(sURL); i8\&J.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _djr>C=H"  
httpConnection.setRequestProperty("User-Agent","NetFox"); c<`Z[EY(t  
String sProperty = "bytes="+nStartPos+"-"; 5gPcsn"D  
httpConnection.setRequestProperty("RANGE",sProperty); TfYXF`d  
Utility.log(sProperty); }T}9AQ}|  
){PL6|5x  
\UdHN=A&  
InputStream input = httpConnection.getInputStream(); 8e`'Ox_5a  
//logResponseHead(httpConnection); gRk%ObJGqm  
QeK@ ++EVc  
G/2| *H  
byte[] b = new byte[1024]; 3=reN6Q  
int nRead; 5w\>Whbd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -gWqq7O  
{ meHnT9a^  
nStartPos += fileAccessI.write(b,0,nRead); D]H@Sx  
//if(nThreadID == 1) :Kl~hzVSOa  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aIrQ=}  
} 'Y ZYRFWXM  
t4a/\{/#9|  
RJo"yB$1e6  
Utility.log("Thread " + nThreadID + " is over!"); 7>Af"1$g  
bDownOver = true; 8| 6:  
//nPos = fileAccessI.write (b,0,nRead); C6=P(%y  
} {xw"t9(fE  
catch(Exception e){e.printStackTrace ();} 'w?*4H  
} CnJrJ>l  
} 9 a ED6  
tFY;q##z  
Mpfdl65  
//打印回应的头信息 gy Jx>i  
public void logResponseHead(HttpURLConnection con) s~@4  
{ tSr.0'CE  
for(int i=1;;i++) ;b(*Bh<  
{ `CW I%V  
String header=con.getHeaderFieldKey(i); Op&i6V}<s  
if(header!=null) gEVN;G'B<=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {bxTODt@  
Utility.log(header+" : "+con.getHeaderField(header)); wj-=#gyAoo  
else ?onaJ=mT  
break; PdUlwT? 8C  
} mgIB8D+6  
} jE /pba4R  
xWwQm'I2}  
7oPLO(0L  
public void splitterStop()  q q%\  
{ {*gO1TZt9  
bStop = true; ~ .}  
} ~uF%*  
w4m -DR5  
^sLnKAN  
} }:5_vH0  
hJr cy!P<a  
cQ= "3M)~r  
/* X @;o<2^  
**FileAccess.java *Nv!Kuk  
*//文件访问(定位,写) -8j<`(M' 5  
package NetFox; >/*wlY!E  
import java.io.*; L/2{}l>D  
~FnB!Mh}?  
2~:jg1  
public class FileAccessI implements Serializable{ +(v<_#wR-  
>EVlMt27'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 N! 7r~B   
RandomAccessFile oSavedFile; 7MRu=Z.-b  
long nPos; 28 h3Ayw4  
:lF[k`S T  
!1i(6?~#4  
public FileAccessI() throws IOException yc./:t1at>  
{ N|Cx";,|FZ  
this("",0); / v";u)  
} c\X0*GX  
[x`trypg  
oSmv  (O  
public FileAccessI(String sName,long nPos) throws IOException tTWeOAF  
{ <SiD m-=E  
oSavedFile = new RandomAccessFile(sName,"rw"); 6XVr-ef  
this.nPos = nPos; deD%E-Ja  
oSavedFile.seek(nPos); K\Oz ~,z  
} RR2Q  
0_Gi1)  
68m (%%E@  
public synchronized int write(byte[] b,int nStart,int nLen) VieX 5  
{ w]Q0}Z  
int n = -1; /u9Md3q*'  
try{ ,@+ 7(W  
oSavedFile.write(b,nStart,nLen); E0K'|*  
n = nLen; MA\^<x_?L}  
} k+X=8()k  
catch(IOException e) {@T8i ^EI  
{ ]B;GU  
e.printStackTrace (); Ri$wt.b  
} B{fPj9Y0  
~7Ji+AJA  
s?;rP,{:p  
return n; Z]$RO  
} 1WGcv O)<  
2?3D` `  
t;P%&:"@M  
} !olvP*c"  
[ vU$zZ<  
O34'c_ fZ  
/* W"9?D  
**SiteInfoBean.java e:9CD-  
*/ mZ;W$y SO  
package NetFox; "Aw| 7XII  
_ Je k;N  
EleK*l  
public class SiteInfoBean { Dq/ _#&S  
s : c  
SK2nxZOH  
private String sSiteURL; //Site's URL [aM_.[bf  
private String sFilePath; //Saved File's Path [ m*=Q  
private String sFileName; //Saved File's Name l~.}#$P]  
private int nSplitter; //Count of Splited Downloading File "y R56`=  
&KfRZ`9H  
PV?XpT  
public SiteInfoBean() 7g(,$5  
{//nSplitter的缺省值为5 m?;aTSa  
//default value of nSplitter is 5 <v<TsEI  
this("","","",5); )A]E:]2  
} 3zJbb3e  
6&(gp(F  
b*4[)Yg4  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Hu$]V*rAG  
{ H-%)r&"vn  
sSiteURL= sURL; *wW/nr=\;  
sFilePath = sPath; !:Lb^C;/  
sFileName = sName; Q1qf'u  
this.nSplitter = nSpiltter; '>:mEXK}w  
F^ kH"u[  
mk JS_6  
} 6[BQx)7T  
lhm=(7Y  
1nh2()QI[  
public String getSSiteURL() }+U} [G  
{ #84pRU~  
return sSiteURL; H27J kZ&  
} 0dhJ# [Y  
Dx/!^L02  
ehEXC  
public void setSSiteURL(String value) $rf4h]&<  
{ '>(R'g42n  
sSiteURL = value; J&~nD(&TY  
} i70TJk$fs  
4VE7%.z+  
Yck(Fl  
public String getSFilePath() Qg+0(odd  
{ 2Mx9Kd'a r  
return sFilePath; P>%\pCJ])  
} nGA'\+zj L  
}9fH`C/m  
ShanwaCDqv  
public void setSFilePath(String value) o uKID_ '  
{ U6qv8*~  
sFilePath = value; >`DbT:/<  
} !Y_"q^5GG'  
s)%RmsdL  
Xr~6_N{J  
public String getSFileName() eW)(u$C|qL  
{ l)E \mo 8  
return sFileName; -}k'a{sj=  
} i> Ssp  
*zX*k 7LnV  
e47JLW&b  
public void setSFileName(String value) 'Omi3LXfDT  
{ v=?U{{xQ  
sFileName = value; ?iG}Qj@5  
} ]B0 >r^  
b3e:F{n ^  
V#!ihL/>  
public int getNSplitter() MrjET!`.jC  
{ zmy94Y5PE  
return nSplitter; F.?`<7  
} %>'2E!%  
(A?{6  
VP=(",`  
public void setNSplitter(int nCount) 9}kN9u  
{ { 'Hi_b3  
nSplitter = nCount; ^[XxE Lx  
} IXt2R~b  
} 8%JxXtWW`  
UiS9uGj  
w.J[3m/  
/* 8^=g$;g  
**Utility.java (r`+q[  
*/ m}0US;c#f  
package NetFox; I.tJ4  
8 f%@:}H  
c\UVMyE  
public class Utility { |x["fWK  
]CH@ T9d5V  
: N ^1T6v  
public Utility() )eGGA6G  
{ 8YraW|H  
#/@U|g  
xBU\$ToC  
} g~.,-V}  
`|wH=  
//线程睡眠 OYC4iI  
public static void sleep(int nSecond) ;6t>!2I>C  
{ SqFya  
try{ $-"AMZ899  
Thread.sleep(nSecond); 8,YF>O&  
} _)2.#L  
catch(Exception e) RGhl` ;  
{ v83uGEq(  
e.printStackTrace (); hxx,E>k  
} xPb;_~  
} 4 C[,S|J  
;|w &n  
//日志 # j*$ `W;  
public static void log(String sMsg) nFW^^v<  
{ '0X!_w6W  
System.err.println(sMsg); twt Bt L  
} |`s}PcV  
s8}:8  
Di9yd  
public static void log(int sMsg) x `PIJE  
{ =b32E^z,  
System.err.println(sMsg); b@^M|h.Va  
} t2p/NIn  
} yt>Pf <AI  
T =3te|fv  
p1v:X?  
/* h@Ea$1'e,  
**TestMethod.java kR^7Z7+#*  
*/ nX5*pTfjL3  
package NetFox; @ 5 kKMz  
fj0+a0h  
PZNo.0M70  
public class TestMethod { rZu_"bcJ  
)g:UH Ns  
34YYw@?}Y  
public TestMethod() HCHP15otfe  
{ ///xx/weblogic60b2_win.exe $DA0lY\  
try{ &-<"HW  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?MKf=! w  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); kSU5  }  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n#z^uq|v  
fileFetch.start(); \2_>$:UoV  
} :1_hQeq  
catch(Exception e){e.printStackTrace ();} PC\Xm,,  
x)"=*Jj  
a47Btd'm  
} P|h<|Gcp  
bIp;$ZHy`K  
hp-< 8Mf  
public static void main(String[] args) [2i+f <  
{ 7S] h:q%%  
new TestMethod(); 82$By]Y9  
} yp@mxI@1  
} !Q.c8GRUQ  
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