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http断点续传简单实现(java)

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/* lHgs;>U$  
**SiteFileFetch.java &0f5:M{P  
*/ %v20~xW :o  
package NetFox; 9z6XF]A  
import java.io.*; N F)~W#  
import java.net.*; dOa%9[  
jKt7M>P  
Eke5Nb  
public class SiteFileFetch extends Thread { |:8bNm5[  
2-Y<4'>  
TB0 5?F  
SiteInfoBean siteInfoBean = null; //文件信息Bean !K|5bK  
long[] nStartPos; //开始位置 (5]}5W*  
long[] nEndPos; //结束位置 <b,~:9*?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 oudxm[/U  
long nFileLength; //文件长度 D3|I:Xm  
boolean bFirst = true; //是否第一次取文件 9on@Q_7m  
boolean bStop = false; //停止标志 ~69&6C1Ch  
File tmpFile; //文件下载的临时信息  w@,zFV  
DataOutputStream output; //输出到文件的输出流 P.gb 1$7<  
'7O3/GDK  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) bhniB@<  
public SiteFileFetch(SiteInfoBean bean) throws IOException 13taFV dU  
{ N7e"@Ic  
siteInfoBean = bean; 03C0L&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]+X@ 7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); t.mVO]dsj  
if(tmpFile.exists ()) -GxaV #{  
{ m*JaXa  
bFirst = false; UFMA:o,  
read_nPos(); eM8}X[  
} |1j["u1  
else F$)[kP,wtO  
{ Y]&j,j&  
nStartPos = new long[bean.getNSplitter()]; .V,@k7U,V  
nEndPos = new long[bean.getNSplitter()]; wmTb97o  
} .9wk@C(Eh_  
=?!wXOg_  
;+"+3  
V:y'Qf2M  
} F w?[lS  
M3.do^ss  
@;"|@!l|  
public void run() WlU0:(d  
{ 7 qS""f7  
//获得文件长度 _bNzXF  
//分割文件 7Op>i,HZk\  
//实例FileSplitterFetch >7 ="8  
//启动FileSplitterFetch线程 i{`:(F5*  
//等待子线程返回 v/_  
try{ c Vc-  
if(bFirst) 6Yln, rC  
{ ?` ?)QE8  
nFileLength = getFileSize(); nR*ryv  
if(nFileLength == -1) *WuID2cOI  
{ zolt$p  
System.err.println("File Length is not known!"); 2Wdyxj Q  
} 7<*yS310  
else if(nFileLength == -2) +~p88;  
{ -qGa]a  
System.err.println("File is not access!"); m^zUmrj[  
} 6e |*E`I  
else HAa; hb  
{ yU*8|FQbP  
for(int i=0;i<nStartPos.length;i++) YuO.yh_  
{ tS6qWtE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \2h!aRWR  
} M!o##* *`  
for(int i=0;i<nEndPos.length-1;i++) a^I\ /&aw'  
{ VXwU?_4J.  
nEndPos = nStartPos[i+1]; #"G]ke1l$  
} rbWP78  
nEndPos[nEndPos.length-1] = nFileLength; -Ps!LI{@  
} *_d7E   
} X9V*UXTc  
;>Ib^ov  
@J/K-.r  
//启动子线程 XwJ7|cB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ) AvN\sC  
for(int i=0;i<nStartPos.length;i++) ?Wlb3;  
{ 3ca (i/c  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {ttysQ-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [D I+~F  
nStartPos,nEndPos,i); ?82xdp g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >G25m'&,7  
fileSplitterFetch.start(); = %TWX[w  
} 9dx/hFA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rD 3v$B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <eWf<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^'PWI{ O  
nEndPos = " + nFileLength); xqu}cz  
// fileSplitterFetch[nPos.length-1].start(); K  &N  
{'NvG  
cQ R]le %(  
//等待子线程结束 ]>5/PD,wWy  
//int count = 0; s;ls qQk  
//是否结束while循环 vg32y /l]S  
boolean breakWhile = false; :74y!  
u0 `S5?  
T4Pgbop  
while(!bStop) {8W'%\!=  
{ m;GCc8  
write_nPos(); )"7iJb<E  
Utility.sleep(500); ?^al9D[:lz  
breakWhile = true; Pd_U7&w,5  
!Dn,^  
at,XB.}Z]  
for(int i=0;i<nStartPos.length;i++) p8Qk 'F=h  
{ SE1=>S%p  
if(!fileSplitterFetch.bDownOver) vdc\R?  
{ ek*rp`y]  
breakWhile = false; x??+~$}\*-  
break; |ATvS2  
} +%h8r5o1  
} c(xrP/yOwi  
if(breakWhile) Ng2twfSl$  
break; \@c,3  
52Z2]T c ,  
LTQ"8  
//count++; &]|?o_p3W  
//if(count>4)  iu=7O  
// siteStop(); mn"G_I  
} 8e1UmM[  
2*laAB  
vXrx{5gz  
System.err.println("文件下载结束!"); (c=6yV@  
} / *#r`A  
catch(Exception e){e.printStackTrace ();} - M4J JV(  
} dO! kk"qn  
^BikV  
*av<E  
//获得文件长度 E Nh l&J  
public long getFileSize() Q{>+ft U  
{ -b9\=U[  
int nFileLength = -1; @=}0`bE  
try{ SJn;{X>)q  
URL url = new URL(siteInfoBean.getSSiteURL()); [}E='m}u9+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /[ 5gX^A  
httpConnection.setRequestProperty("User-Agent","NetFox"); On9A U:\  
m$>H u@Va  
Rq'S>#e  
int responseCode=httpConnection.getResponseCode(); PR#exm&  
if(responseCode>=400) nv|NQ Tk  
{ 7rc0yB  
processErrorCode(responseCode); X9W@&zQ  
return -2; //-2 represent access is error ]8_NZHld  
} -P$PAg5"2  
8mvy\l EEH  
K7_UP&`=J  
String sHeader; BU/"rv"(Fg  
ohGJ1  
_7Ju  
for(int i=1;;i++) 4yy>jXDG  
{ dd%6t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); JE "x  
//Utility.log(in.readLine()); q$d>(vb q  
sHeader=httpConnection.getHeaderFieldKey(i); AUG#_HE]k  
if(sHeader!=null) c<:-T  
{ t6 "%3#s  
if(sHeader.equals("Content-Length")) r= `Jn6@  
{ ^1I19q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |.: q  
break; [6Izlh+D  
} q_[o" wq/  
} ]nn98y+  
else %D{6[8  
break; i &nSh ]KK  
} iy.p n  
} G" qv z{*  
catch(IOException e){e.printStackTrace ();} {L{o]Ii?g  
catch(Exception e){e.printStackTrace ();} _}Ac n$  
HmGWht6R  
o q Xg  
Utility.log(nFileLength); Ju@c~Xm  
EHJ.T~X  
g*AWE,%=|  
return nFileLength; *a M=Z+  
} ,q`\\d  
Xx~Bp+  
jp%S3)  
//保存下载信息(文件指针位置) `KoV_2|  
private void write_nPos()  ~^:A{/  
{ T4Uev*A  
try{ <44G]eb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hD 82tr  
output.writeInt(nStartPos.length); oWT3apGO  
for(int i=0;i<nStartPos.length;i++) *w`sM%]Rq  
{ Z"xvh81P  
// output.writeLong(nPos); 2*& ^v  
output.writeLong(fileSplitterFetch.nStartPos); vm8eZG|  
output.writeLong(fileSplitterFetch.nEndPos);  ?(1 y  
} `g=J%p  
output.close(); |mfvr *7  
} -$ls(oot  
catch(IOException e){e.printStackTrace ();} 4SxX3Fw  
catch(Exception e){e.printStackTrace ();} q"lSZ; 'E  
} <dtGK~_  
+5*95-;0  
>1Ibc=}g  
//读取保存的下载信息(文件指针位置) V~3a!-m\  
private void read_nPos() N#_H6TfMG  
{ L,/%f<wd  
try{ L~OvY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); b{&)6M)zo  
int nCount = input.readInt(); M'O <h  
nStartPos = new long[nCount]; pz}.9 yI8  
nEndPos = new long[nCount]; %YscBG  
for(int i=0;i<nStartPos.length;i++) Czu9o;xr  
{ )qw&%sO +  
nStartPos = input.readLong(); CY5Z{qiX  
nEndPos = input.readLong(); EI%89i`3^  
} A}9`S6@@  
input.close(); K($Npuu]  
} (y~TL*B  
catch(IOException e){e.printStackTrace ();} mO7]9 p  
catch(Exception e){e.printStackTrace ();} WSB 0~+  
} $Ds2>G4c  
B~ GbF*j  
77f9(~ZnT  
private void processErrorCode(int nErrorCode) N =}A Z{$  
{ U%QI a TN*  
System.err.println("Error Code : " + nErrorCode); zwjgE6  
} [}=B8#Jl-C  
![=yi tB  
f}P3O3Yv&  
//停止文件下载 !*N@ZL&X  
public void siteStop() 4Z&lYLq;  
{ F^;ez/Gl  
bStop = true; gR;i(81U  
for(int i=0;i<nStartPos.length;i++) X.{S*E:$u  
fileSplitterFetch.splitterStop(); \~$#1D1f  
N~)_DjQP5  
ea 'D td  
} SY\ gXO8k  
} ",; H`V  
//负责部分文件的抓取 ~B?y{  
**FileSplitterFetch.java qo bc<-  
*/ Ve; n}mJ?  
package NetFox; kdeWip6Y  
(hbyEQhF  
*^ZV8c}  
import java.io.*; m-#2n? z-  
import java.net.*; V U3upy<  
`Ggbi4),  
JK5gQ3C[  
public class FileSplitterFetch extends Thread {  ZBp/sm  
%dVZ0dl  
H<,gU`&R  
String sURL; //File URL $'M!HJxb  
long nStartPos; //File Snippet Start Position iqWQ!r^  
long nEndPos; //File Snippet End Position on `3&0,.  
int nThreadID; //Thread's ID 6LIJ Q  
boolean bDownOver = false; //Downing is over m;QMQeGz  
boolean bStop = false; //Stop identical hz@bW2S.  
FileAccessI fileAccessI = null; //File Access interface E ~<JC"]  
rjYJs*#  
G_,jgg7  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >|UOz&  
{ %IWPM"  
this.sURL = sURL; 2FJ*f/  
this.nStartPos = nStart; Tyx_/pJT  
this.nEndPos = nEnd; 3f{3NzN  
nThreadID = id; lt8|9"9<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @Jw-8Q{  
} SE  %pw9  
kt:! 7  
D'Q\za  
public void run() EaN6^S=  
{ s2'h  
while(nStartPos < nEndPos && !bStop) -[.[>&`/  
{ u'BaKWPS  
4|?;TE5  
1=V-V<  
try{ h2d(?vOT  
URL url = new URL(sURL); xwo<' xT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MQ8J<A Pf-  
httpConnection.setRequestProperty("User-Agent","NetFox"); $ddCTS^  
String sProperty = "bytes="+nStartPos+"-"; $xN|5;+  
httpConnection.setRequestProperty("RANGE",sProperty); fNFY$:4X  
Utility.log(sProperty); }pkzH'$HJ  
C~/a-  
J)-x!y>  
InputStream input = httpConnection.getInputStream(); Sdryol<  
//logResponseHead(httpConnection); $=4QO  
0L52#;?Si"  
]c'A%:f<  
byte[] b = new byte[1024]; C?eH]hkZ3  
int nRead; <Q3c[ Y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .$vK&k  
{ 7qS)c}Q\  
nStartPos += fileAccessI.write(b,0,nRead); Y}wyw8g/  
//if(nThreadID == 1) oUlVI*~ND  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A*BeR0(  
} Cw&KVw*  
H qx-;F~0  
xJ.M;SF4  
Utility.log("Thread " + nThreadID + " is over!"); utV_W&  
bDownOver = true; IH+|}z4N?>  
//nPos = fileAccessI.write (b,0,nRead); + {'.7#  
} x[e<} 8'$(  
catch(Exception e){e.printStackTrace ();} =rdV ]{Wc  
} Zj'9rXhrM1  
} Z *x'+X  
CpT jJXb  
l.M0`Cn-%  
//打印回应的头信息 U 6)#}   
public void logResponseHead(HttpURLConnection con) h/Y'<:  
{ Lr pM\}t  
for(int i=1;;i++) scV5PUq  
{ |2A:eI8 ^  
String header=con.getHeaderFieldKey(i); SOIN']L|V[  
if(header!=null) do'GlU oMC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'LDQgC*%  
Utility.log(header+" : "+con.getHeaderField(header)); <N~K ;n v  
else 4#Jg9o   
break; A@#E@ ;lm  
} p6S8VA  
} =Dj#gV  
"\yT7?},  
2GG2jky{/  
public void splitterStop() TWX.D`W  
{ =?8@#]G+  
bStop = true; 2&cT~ZX&'  
} ftSW (og  
v`T c}c '  
Zv{'MIv&v  
} wC'Szni  
#KvlYZ+1  
CWKm(@"5  
/* (/$^uWj  
**FileAccess.java {P-):  
*//文件访问(定位,写) 1|=A*T-<M  
package NetFox; |Y.?_lC  
import java.io.*; {M)Nnst"~  
0=$T\(0g  
h{qgEIk&  
public class FileAccessI implements Serializable{ +b 6v!7_  
yB!dp;gM{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |I=T @1_D  
RandomAccessFile oSavedFile; +kD R.E:  
long nPos; `WS&rmq&'  
v"0J&7!J  
DHRlWQox  
public FileAccessI() throws IOException * v#o  
{ ;kKyksxlD  
this("",0); dc'Y `e  
} m4Zk\,1m.|  
-nwypu  
F"mmLao  
public FileAccessI(String sName,long nPos) throws IOException %"-5 <6d  
{ %z$#6?OK^  
oSavedFile = new RandomAccessFile(sName,"rw"); !()Qm,1u  
this.nPos = nPos; ;9#KeA _  
oSavedFile.seek(nPos); J .<F"r>  
} |V(0GB  
yt2PU_),  
6L~n.5B~o  
public synchronized int write(byte[] b,int nStart,int nLen) 4^d?D!j  
{ 0*v2y*2V  
int n = -1; XK vi=0B  
try{ $:^td/p J  
oSavedFile.write(b,nStart,nLen); ,#K'PB4E  
n = nLen; [D1Up  
} 19] E 5'AI  
catch(IOException e) ee=D1qNu;  
{ +w~oH=  
e.printStackTrace (); Uw:"n]G]D?  
}  0+8e,  
|vC~HJpuv'  
Pzem{y7Ir  
return n; 1 -b_~DF  
} %l%HHT  
K)P%;X  
!@"OB~  
} rZpXPI  
QsW/X0YBv  
Fj!U|l\_9  
/* H;"4 C8K7  
**SiteInfoBean.java !`r$"}g  
*/ ajpX L  
package NetFox; 8?C5L8)  
47B&s   
5-A\9UC*@  
public class SiteInfoBean { _VXN#@y  
"gwSJ~:ds  
*K; ~!P  
private String sSiteURL; //Site's URL -n;}n:w L  
private String sFilePath; //Saved File's Path WY]s |2a  
private String sFileName; //Saved File's Name d"Y{UE  
private int nSplitter; //Count of Splited Downloading File yCo.cd-  
d d;T-wa}  
%jM,W}2  
public SiteInfoBean() LH6 vLuf  
{//nSplitter的缺省值为5 }PpUAt~g  
//default value of nSplitter is 5 T^q 0'#/  
this("","","",5); L: x-%m%w  
} :E?V.  
g\AY|;T  
M3Kfd  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) b`_Q8 J  
{ j+YJbL v  
sSiteURL= sURL; ,z?':TZ  
sFilePath = sPath; #fM'>$N  
sFileName = sName; ,u!sjx  
this.nSplitter = nSpiltter; B/C,.?Or  
-F>jIgeC2v  
I}Q2Vu<  
} T9&1VW  
3uMy]HUQ  
DTs;{c  
public String getSSiteURL() }~q5w{_n  
{ ']oQ]Yx0  
return sSiteURL; w*Ihk)  
} {>;R?TG]$  
L0]_X#s>#  
&.ACd+Cd  
public void setSSiteURL(String value) <-0]i_4sK  
{ 92-I~ !d  
sSiteURL = value; WPDyu.QD  
} A)KZa"EX  
0BsYavCR  
2TuU2 f.  
public String getSFilePath() y> (w\K9W  
{ xLn%hxm?,  
return sFilePath; H[|~/0?K  
} d!{r  v  
Dhv3jg;lq  
B1Oq!k  
public void setSFilePath(String value) \[nut;  
{ =Runf +}  
sFilePath = value; |&jXp%4T  
} Rva$IX ^]  
YoE3<[KD(  
JN6B~ZNf  
public String getSFileName() 'm9` 12 H  
{ uVU)d1N  
return sFileName; rQ9'bCSr%  
} P>6{&(  
k_R"CKd  
`,0}ZzaV&  
public void setSFileName(String value) tI{_y  
{ @lt#Nz  
sFileName = value; 1nOCQ\$l  
} /Q )\+  
|Ds=)S" K  
A(N4N  
public int getNSplitter() 1&$ nVQ  
{ +^<](z  
return nSplitter; cGD(.=  
} \C1nZk?3  
,=N.FS  
$7uA%|\  
public void setNSplitter(int nCount) HorDNRyu  
{ p<;0g9,1  
nSplitter = nCount; #D|p2L$  
} |)G<,FJQE_  
} Xry4 7a )  
%07SFu#  
l@:0e]8|o  
/* $mB;K]m  
**Utility.java PxE3K-S)G  
*/ Lh<).<S  
package NetFox; 6aV_@no.C  
hpJ-r  
PYzvCf`?  
public class Utility { &VcV$8k  
]+$?u&0?w  
[trwBZ^D~  
public Utility() bJ;'`sw1  
{ ;UP$yM;  
E.>4C[O  
2Hv+W-6v  
} yiI1x*^  
>"<Wjr8W!$  
//线程睡眠 3yXY.>'  
public static void sleep(int nSecond) EZ`{Wnbq  
{  RX5dO%  
try{ s|ITsz0,td  
Thread.sleep(nSecond); b_):MQ1{  
} xP,hTE  
catch(Exception e) jNy.Y8E&  
{ V470C@  
e.printStackTrace (); 5PnDN\  
} <d_!mKw  
} @OHm#`~  
H7j0K~U0  
//日志 4a]P7fx-  
public static void log(String sMsg) &! ?eL  
{ <"|,"hA  
System.err.println(sMsg); GM<-&s!Uj  
} b%5f&N  
OBAi2Vw  
&8 x-o,  
public static void log(int sMsg) yvYad  
{ K96<M);:g  
System.err.println(sMsg); (!N|Kl  
} JO< wU  
} ?I@W:#>o  
bY0|N[ g  
o0vUj  
/* _ORvo{[:  
**TestMethod.java ;d9QAN&0}  
*/ '08=yqy4N  
package NetFox; I 2|Bg,e  
^v`\x5"Vp  
W{gb:^;zb  
public class TestMethod { 6i~WcAs  
Ez=Olbk  
# 4PVVu<  
public TestMethod() &pp|U}  
{ ///xx/weblogic60b2_win.exe :[!j?)%>  
try{ ]P?vdgEM&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C 6AUNRpl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z/;aT -N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Nu7 !8[?r*  
fileFetch.start(); w*JGUk  
} 9p2&) kb6  
catch(Exception e){e.printStackTrace ();} cjIh}:| '  
{,~3.5u   
6f*CvW  
} & 9 ?\b7  
w)Qp?k d  
j^2wb+`  
public static void main(String[] args) /RC7"QzL  
{ qeZ? 7#Gf  
new TestMethod(); 46&/gehr  
} NPe%F+X  
} 4Wm@W E  
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