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http断点续传简单实现(java)

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/* Y?T{>"_W  
**SiteFileFetch.java ]T4/dk&|o^  
*/ OZ,kz2SF#  
package NetFox; )?L=o0  
import java.io.*; pm&TH d  
import java.net.*; 3dShznlf_*  
IUcL*  
pJpapA2l*6  
public class SiteFileFetch extends Thread { "n-'?W!  
( ?V`|[+u  
<#63tN9  
SiteInfoBean siteInfoBean = null; //文件信息Bean W L$^B@gXQ  
long[] nStartPos; //开始位置 P:qmg"i@3  
long[] nEndPos; //结束位置 T5BZD +Ta  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )&DAbB!O  
long nFileLength; //文件长度 YeX*IZX8  
boolean bFirst = true; //是否第一次取文件 +Q*`kg'  
boolean bStop = false; //停止标志 =lXj%V^8N  
File tmpFile; //文件下载的临时信息 30Yis_l2h  
DataOutputStream output; //输出到文件的输出流 $EMOz=)I#  
# kI>  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) <_tmkLeZf  
public SiteFileFetch(SiteInfoBean bean) throws IOException KWwtL"3  
{ W+nu=iQ!  
siteInfoBean = bean; zd?@xno  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9N ]Xa  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^6 6!f 5^W  
if(tmpFile.exists ()) #c!:&9oU  
{ y!e]bvN  
bFirst = false; OI R5QH  
read_nPos(); ;?6vKpj;  
} OfsP5*d  
else y>{: [L9*  
{ ZTC>Ufu2!  
nStartPos = new long[bean.getNSplitter()]; UNI< r  
nEndPos = new long[bean.getNSplitter()]; #XV=,81w  
} ~Eut_d  
eh# 37*-  
IS C.~q2  
<QtZ6-;_f  
} *2X6;~  
^s,3*cAU  
h#rP]o@  
public void run() y)f.ON36I  
{ G#iQX`  
//获得文件长度 (Guzj*12  
//分割文件 R^Rc!G}  
//实例FileSplitterFetch \lL[08G  
//启动FileSplitterFetch线程 Q&m85'r5X  
//等待子线程返回 Wj{lb_Rj  
try{ )W@u g,y  
if(bFirst) U~ {k_'-i  
{ S"Al [{  
nFileLength = getFileSize(); ;yH>A ;,K%  
if(nFileLength == -1) 337.' |ZE  
{ =j]y?;7q  
System.err.println("File Length is not known!"); | %_C$s%  
} {f*Y}/@  
else if(nFileLength == -2) }A9#3Y|F  
{ 3CUQQ_  
System.err.println("File is not access!"); "EW8ll7r  
} 6)HmE[[F  
else GR,2^]<{  
{ <H[w0Z$  
for(int i=0;i<nStartPos.length;i++) /iW+<@Mas  
{ 2Gyq40  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >Wg= Tuef  
}  yCX5 5:  
for(int i=0;i<nEndPos.length-1;i++) ?y>N&\pt2  
{ Iil2R}1  
nEndPos = nStartPos[i+1]; @uSO~. 7  
} d[9,J?'OQ  
nEndPos[nEndPos.length-1] = nFileLength; ktu?-?#0,  
} '.}}k!#  
} B`pBIUu  
G T>'|~e  
?7\V)$00(&  
//启动子线程 w+$$uz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; OM'iJB6=  
for(int i=0;i<nStartPos.length;i++) W 4{ T<  
{ T2{e 1 =Z7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UBo0c?,4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IPo t][ N>  
nStartPos,nEndPos,i); B=Hd:P|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *i#2>=)  
fileSplitterFetch.start(); ;_sJ>.=\  
} %$BRQ-O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yoE-a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {uDW<u_!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =D zrM%  
nEndPos = " + nFileLength); a%go[_w  
// fileSplitterFetch[nPos.length-1].start(); 2"0VXtv6  
4+olyBht  
L3]J8oEmU  
//等待子线程结束 !~^2Mu(X  
//int count = 0; gx\V)8Zr  
//是否结束while循环 =lNW1J\SW  
boolean breakWhile = false; jAQ{H  
bR`5g  
:?f<tNU$  
while(!bStop) ui]iO p  
{ 01Jav~WR  
write_nPos(); 6v@Prw@.b  
Utility.sleep(500); C&O8fNB_  
breakWhile = true; f,YORJ  
]t[%.^5#  
A-x^JC=  
for(int i=0;i<nStartPos.length;i++) eI-fH  
{ g5BL"Dn  
if(!fileSplitterFetch.bDownOver) )\U:e:Zae  
{ qw+ 7.h#V  
breakWhile = false; e]<Syrk  
break; wXNng(M7  
} DLwlA !z  
} fb f&bJT  
if(breakWhile) |dIR v  
break; :GvC#2 p  
e.\>GwM  
w+m7jn!$  
//count++; EXdX%T\  
//if(count>4) s:<y\1Ay  
// siteStop(); BDt$s( \  
} (~|)Gmq2  
NbWEP\dS'z  
nS#F*)  
System.err.println("文件下载结束!"); x ]VycS  
} +5fB?0D;  
catch(Exception e){e.printStackTrace ();} ~#g c{ C@  
} lG6&uMvo  
_d!sSyk`  
y9}qB:[bR  
//获得文件长度 [w](x  
public long getFileSize() *gmc6xY  
{ {UH45#Ua  
int nFileLength = -1; sta/i?n  
try{ :M6|V_Yp  
URL url = new URL(siteInfoBean.getSSiteURL()); yCz"~c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =u0=)\0@r  
httpConnection.setRequestProperty("User-Agent","NetFox"); `&I6=,YLp  
,WdSJ BK'a  
=Vh]{ y~$  
int responseCode=httpConnection.getResponseCode(); JKKp5~_~  
if(responseCode>=400) A._CCou  
{ ]:ca=&>  
processErrorCode(responseCode); 52^3N>X4X  
return -2; //-2 represent access is error ?Gf'G{^}  
} ,T;sWl  
!/`AM<`o  
@3eMvbI  
String sHeader; qY&(O`?m&  
Sw$&E  
.}E<,T  
for(int i=1;;i++) #WA7}tHb  
{ D}%VZA}].  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [YQtX_;w  
//Utility.log(in.readLine()); -X*.scw  
sHeader=httpConnection.getHeaderFieldKey(i); "-fyX!  
if(sHeader!=null) %AV3eqghCg  
{ z}.!q{Q  
if(sHeader.equals("Content-Length")) >hoIJZP,  
{ "Ol;0>$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); H$KE*Wwq  
break; )&1yt4 x6%  
} aO.'(kk8  
} &JAQ:([:  
else fU@}]&  
break; >C+0LF`U  
} 0(|R N V_  
} GC66n1- X  
catch(IOException e){e.printStackTrace ();} ^%~ztn 51  
catch(Exception e){e.printStackTrace ();} cE 8vSQ%  
$ ;>,  
9<kKno  
Utility.log(nFileLength); n} GIf&  
pWSYbN+d  
VxjEKc  
return nFileLength; E87/B%R  
} EAF<PMb  
v|VY5vN  
jPP aL]  
//保存下载信息(文件指针位置) -le:0NUwI  
private void write_nPos() po*s  
{ `=uCp^ +v  
try{ v!t*Ng  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *D~@xypy  
output.writeInt(nStartPos.length); uQ&&? j  
for(int i=0;i<nStartPos.length;i++) &|%z!x6f  
{ tH 5f;mY,  
// output.writeLong(nPos); + h`:qB  
output.writeLong(fileSplitterFetch.nStartPos); :|<D(YA  
output.writeLong(fileSplitterFetch.nEndPos); ]O<Yr'  
} vMzR3@4e  
output.close(); N TXT0:  
} s.1(- "DU  
catch(IOException e){e.printStackTrace ();} q]<Xx{_  
catch(Exception e){e.printStackTrace ();} P{(m:`N  
} a&#Z=WK4  
@MtF^y  
g]$>G0E`oD  
//读取保存的下载信息(文件指针位置) aC]~   
private void read_nPos() IL3,dad'^  
{ (S5'iks x  
try{ mt fDl;/D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O~{Zs\u9  
int nCount = input.readInt(); jA=uK6m  
nStartPos = new long[nCount]; 7*'_&0   
nEndPos = new long[nCount]; >+u5%5-wr  
for(int i=0;i<nStartPos.length;i++) dAEz hR[=  
{ 5PKv@Mk  
nStartPos = input.readLong(); KPW: r#d  
nEndPos = input.readLong(); t@}<&{zk  
} lxbbyy25  
input.close(); '  AeU  
} cJ!wZT`  
catch(IOException e){e.printStackTrace ();} DbPw) aCj  
catch(Exception e){e.printStackTrace ();} 8k_,Hni  
} 8C,?Ai<ro  
xhUQ.(S`r6  
@#VxjXW^  
private void processErrorCode(int nErrorCode) 4$IPz7  
{ e{=7,DRH<  
System.err.println("Error Code : " + nErrorCode); )KXLL;]  
} ^Xa-)Pu  
8"oS1W  
r+m8#uR  
//停止文件下载 w/YKWv{_S  
public void siteStop()  `Yoafa  
{ qf)]!w U9  
bStop = true; YLPiK  
for(int i=0;i<nStartPos.length;i++) WpTC,~-  
fileSplitterFetch.splitterStop(); T]CvfvO5  
gP/]05$e  
1O(fI|gcO  
} E_ mgYW*5  
} Qx.E+n\  
//负责部分文件的抓取 lJ7k4ua\  
**FileSplitterFetch.java ? ~_%I  
*/ K\?vTgc(  
package NetFox; z W+wtYV4  
O "{o (  
(B$2)yZY  
import java.io.*; [c>X Q  
import java.net.*; L x9`y t6  
QZh8l-!#5  
:&_@U$  
public class FileSplitterFetch extends Thread { x!I7vs~~zW  
<&H.pN1_  
{tWfLfzU  
String sURL; //File URL A\4 Gq  
long nStartPos; //File Snippet Start Position F+hsIsQ  
long nEndPos; //File Snippet End Position 7RdL/21K  
int nThreadID; //Thread's ID _^SNI~  
boolean bDownOver = false; //Downing is over VJ;'$SYx  
boolean bStop = false; //Stop identical W9eR3q  
FileAccessI fileAccessI = null; //File Access interface zaoZCyJT%  
]&}?J:+?0E  
P_b00",S  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )Xg#x:  
{ (q +Q.Q  
this.sURL = sURL; -O(.J'=8  
this.nStartPos = nStart; Q@d X2  
this.nEndPos = nEnd; Zqx5I~  
nThreadID = id; t$Qav>D  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Q%t8cJ L  
} "h:xdaIE/p  
[dt1%DD`M  
8(g:i#~  
public void run() ->93.sge  
{ > ]6Eb`v  
while(nStartPos < nEndPos && !bStop) bZtjg  
{ gVZ~OcB!W  
 Y9PG  
%PkJ7-/b|^  
try{ 2Db[dk( ]  
URL url = new URL(sURL); -.z~u/uL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4|Z3;;%+  
httpConnection.setRequestProperty("User-Agent","NetFox"); kyY tL_SD  
String sProperty = "bytes="+nStartPos+"-"; N2~DxVJ5cT  
httpConnection.setRequestProperty("RANGE",sProperty); ri\r%x  
Utility.log(sProperty); a&y%|Gs^f  
q l8CgL  
L0uN|?}  
InputStream input = httpConnection.getInputStream(); >TtkG|/U-T  
//logResponseHead(httpConnection); le8n!Dk(  
meIY00   
5ue{&z @T  
byte[] b = new byte[1024]; t@!oc"z}@  
int nRead; d3Y#_!)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ux-Fvwoh  
{ .;$/nz6vk  
nStartPos += fileAccessI.write(b,0,nRead); .Olq_wuH  
//if(nThreadID == 1) 3YRhqp"E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \mv7"TM  
} G]5'U"cj3  
,gRsbC  
w3yI;P  
Utility.log("Thread " + nThreadID + " is over!"); 5$zC,g*#  
bDownOver = true; [nflQW6  
//nPos = fileAccessI.write (b,0,nRead); r$.ek\D5  
} zXMIDrq  
catch(Exception e){e.printStackTrace ();} >Wy@J]Y#  
} ^WM)UZEBC  
} [n66ZY#U]  
]M= 3Sn8}  
,hX03P-X  
//打印回应的头信息  H\)on"  
public void logResponseHead(HttpURLConnection con) J^1w& 40  
{ ,=z8aiUu  
for(int i=1;;i++) ^V>sNR  
{ [h,T.zpa  
String header=con.getHeaderFieldKey(i); [l'~>  
if(header!=null) #nn2odR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J}<k`af  
Utility.log(header+" : "+con.getHeaderField(header)); O7q-MeMM  
else  aA0aW=R  
break; rX fQ_  
} hv7!x=?8  
} ks'25tv}F  
:9K5zD  
iVnrv`k,  
public void splitterStop() 3Jk;+<  
{ 8[}MXMRdb  
bStop = true; .$S`J2Y  
} ^9"|tWf6O  
N6yqA)z?;  
Fc42TH p  
} blxH`O!  
H}JH339  
&*L:4By)]  
/* CWt,cwFW  
**FileAccess.java j'CRm5O  
*//文件访问(定位,写) o_os;  
package NetFox; _Z5l Nu  
import java.io.*; _0^<)OSY  
sDWX} NV  
0B1*N_.L@  
public class FileAccessI implements Serializable{ Wu:vO2aw8  
r~TiJ?8I  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *F~"4g  
RandomAccessFile oSavedFile; +<@7x16  
long nPos; ?$F:S%eH  
Qe]@`Vg  
[*8w v^  
public FileAccessI() throws IOException QoI@/ jLj  
{ 8R8J./i.K  
this("",0); R7Hn8;..  
} %=\h=\wt  
T" 8>6a@}E  
4$d|}ajH  
public FileAccessI(String sName,long nPos) throws IOException $U"/.Mh\  
{ az0( 54M  
oSavedFile = new RandomAccessFile(sName,"rw"); KdYT5VUM/  
this.nPos = nPos; fy9{W@E3p  
oSavedFile.seek(nPos); /]<0`nI.  
} eJ$?T7aUf  
duV|'ntr  
9?bfZF4A=  
public synchronized int write(byte[] b,int nStart,int nLen) `=b*g24z[N  
{ :#c?`>uV  
int n = -1; m'oVqA&  
try{ W[j =!o  
oSavedFile.write(b,nStart,nLen); {Kd9}CDAZ  
n = nLen; FhAuTZk  
} / D#vs9S  
catch(IOException e) |PDuvv!.f  
{ M+)%gnq`u  
e.printStackTrace (); G-bG}9vc]  
} 9%kY8#%SV  
:14O=C  
aSXoYG0\  
return n; (fm\kV  
} >sPu*8D40a  
"p2 $R*ie  
/Eh\07p  
} RZm5[n  
.Eh~$wm  
'rp(k\ pY  
/* &FkKnz4IZ  
**SiteInfoBean.java |C7GI[P  
*/ yTkYPx  
package NetFox; 5j{o0&=_$  
'1=/G7g  
)'DFDrY  
public class SiteInfoBean { jr" yIC_  
.eK1xwhJ  
`k^ i#Nc>  
private String sSiteURL; //Site's URL ;wJLH\/  
private String sFilePath; //Saved File's Path REQ2pfk0  
private String sFileName; //Saved File's Name 5#$E4k:YV  
private int nSplitter; //Count of Splited Downloading File :v1'(A1t  
1fViW^l_  
[M@i,d-;A  
public SiteInfoBean() iDp]l u  
{//nSplitter的缺省值为5 *z` {$hc  
//default value of nSplitter is 5 {nm#aA%,  
this("","","",5); =qCVy:RL4  
} '[`.&-;  
mr E^D|  
SO]x^+[  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) s-k~_C>Fw  
{ +g7Iu! cA  
sSiteURL= sURL; `^wF]R  
sFilePath = sPath; ;# {XNq<1  
sFileName = sName; ]$y"|xqR  
this.nSplitter = nSpiltter; Rk2ZdNc\  
*~prI1e(  
:==kC672  
} r_FW)Fu^  
I;uZ/cZ|/  
8kH'ai  
public String getSSiteURL() 84e)huAs  
{ qI:}3b;T  
return sSiteURL; xqmJPbA  
} x%vt$dy*8  
^^3 >R`  
nU[ROy5  
public void setSSiteURL(String value) s-*8=  
{ wV W+~DJ  
sSiteURL = value; ) ;-AT^  
} PX\}lTJ  
csH1X/3ha\  
,yAvLY5 P  
public String getSFilePath() `r+e! o  
{ lv&<kYWY  
return sFilePath; Ij@YOt  
} N%_-5Q)so  
dH&N<  
76zi)f1f  
public void setSFilePath(String value) Lo7R^>  
{ Z&JW}''n|F  
sFilePath = value; :*A6Ba  
} A}H)ojG'v  
3::DURkjf  
8'Z9Z*^h#x  
public String getSFileName() xJ^Gtq Um  
{ <y-KW WE  
return sFileName; Eq~&d.j  
} 'u_'y  
M!!W>A@T[g  
S[X bb=n  
public void setSFileName(String value) D-E30b]e  
{ s-o0N{b?#'  
sFileName = value; jP@H$$-=wH  
} (`!?p ^>A  
@e$z Ej5  
Y;xVB" (  
public int getNSplitter() 4SY]Q[  
{ .QRQvtd.  
return nSplitter; H5^ 'J`0\  
} ]*ZL>fuD|  
42ttmN1F  
9_5Fl,u z  
public void setNSplitter(int nCount) 0K@s_C=n#  
{ o-GlBXI;  
nSplitter = nCount; x_2 [+Ol  
} yZUB8erb.  
} 8iqx*8}  
6$ 9n_AS  
`fY~Lv{4d_  
/* "Z&{  
**Utility.java 9~ K 1+%!  
*/ 7W5FHZd'  
package NetFox; M-T&K% /lW  
.!l#z|/x  
wu/]M~XwI  
public class Utility { Z +(V'e;  
jiC;*]n  
b H?dyS6Bx  
public Utility() 'fy1'^VPAV  
{ [-{L@  
|Y0BnyGK  
0p*(<8D}  
} A_CEpG]  
Ac^}wXp  
//线程睡眠 )l\BZndf  
public static void sleep(int nSecond) x\*`i)su  
{ `.#e4 FBW  
try{ 0 #VH=pga  
Thread.sleep(nSecond); N6Vn/7I5%  
} Uj(,6K8W  
catch(Exception e) iVFHr<zk  
{ IgG@v9'  
e.printStackTrace (); zX{ [Z  
} w`CGDF\Oo  
} t(\d;ybyx  
K0g<11}(Yg  
//日志 I}kx;!*b  
public static void log(String sMsg) ,fT5I6l  
{ X%h1r`h&  
System.err.println(sMsg); T,TKt%  
} &g\D-At  
kbI:}b7H  
<q~&g &&+  
public static void log(int sMsg) |F iL1_  
{ q\x*@KQgM  
System.err.println(sMsg); _`+ !,kG[  
} ;v[F@O~*)  
} Fm#4;'x5E  
wbU pD(  
cW/RH.N  
/* DCACj-f  
**TestMethod.java (=j]fnH?  
*/ w5b D  
package NetFox; Vv B%,_\  
^; Nu\c  
B;SYO>.W  
public class TestMethod { >Yl?i&3n  
IMmoq={ (z  
I%h9V([  
public TestMethod() %t([  
{ ///xx/weblogic60b2_win.exe </5uB' B ^  
try{ :5L9tNr{_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P B.@G,)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4l@*x^F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); xx)egy_  
fileFetch.start(); aW$sd)  
} pUZbZ U  
catch(Exception e){e.printStackTrace ();} V44IA[  
&y[Od{=  
S#/[>Cb  
} z:ue]7(.  
 5%mc|  
/[#<@o  
public static void main(String[] args) X|{TwmHd  
{ @SF*Kvb&  
new TestMethod(); 2ro4{^(_  
} f]tc$`vb  
} u7=`u/  
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