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http断点续传简单实现(java)

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/* ?*r%*CL  
**SiteFileFetch.java 84reyA  
*/ q #7Nk)<.  
package NetFox; f\Hw Y)^>  
import java.io.*; :A:7^jrhi  
import java.net.*; 4,h)<(d{  
Qp)?wny4  
{Oq8A.daJ  
public class SiteFileFetch extends Thread { Ruq>+ }4  
MU2kA&LH  
N;BuBm5K  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1>Vq<z  
long[] nStartPos; //开始位置 A-_M=\  
long[] nEndPos; //结束位置 T /IX(b'<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H"k\(SPVS  
long nFileLength; //文件长度 4g}r+!T  
boolean bFirst = true; //是否第一次取文件 92.Rjz;=9?  
boolean bStop = false; //停止标志 &y|PseH"  
File tmpFile; //文件下载的临时信息 8g-Z~~0W1  
DataOutputStream output; //输出到文件的输出流 E_[a|N"D  
U 0~BcFpD  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) {D(l#;,iX2  
public SiteFileFetch(SiteInfoBean bean) throws IOException `k8jFB C  
{ BD}%RTeWKq  
siteInfoBean = bean; x?u@ j7[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); S?a4 IK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); iC^91!<  
if(tmpFile.exists ()) w`+-xT%  
{ ?p 4iXHE  
bFirst = false; V>E7!LIn.  
read_nPos(); c93 Ok|  
} &`vThs[x  
else :[f[-F  
{ +~o f#  
nStartPos = new long[bean.getNSplitter()]; !+z^VcV  
nEndPos = new long[bean.getNSplitter()]; HkhZB^_V  
} LjW32>B  
+|8.ymvm  
,L~aa?Nb-  
8y_(Iu|:  
} c9Cc%EK  
-e_TJA  
=5fY3%^b{  
public void run() YO?o$Hv16  
{ ht>/7.p]  
//获得文件长度 x>BFK@#  
//分割文件 )b=vBs`%  
//实例FileSplitterFetch K7(k_4  
//启动FileSplitterFetch线程 >hq{:m  
//等待子线程返回 O'#;Ge/,  
try{ &b*v7c=o  
if(bFirst) ,,80nW9E  
{ LikCIO  
nFileLength = getFileSize(); "$K]+0ryG<  
if(nFileLength == -1) Z1+Ewq3m  
{ O{7#Xj :_  
System.err.println("File Length is not known!"); !TY0;is  
} *b 0z/ 6  
else if(nFileLength == -2) z j#<X  
{ S Te8*=w  
System.err.println("File is not access!");  F0zaA  
} _1Ne+"V  
else M2d&7>N  
{ qTwl\dcncC  
for(int i=0;i<nStartPos.length;i++) i[FYR;C  
{ tSoF!@6  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); y:$qX*+9e  
} \T<F#a  
for(int i=0;i<nEndPos.length-1;i++) i;]# @n|  
{ !Icznou\  
nEndPos = nStartPos[i+1]; DKem;_6OQ  
} upZc~k!1\  
nEndPos[nEndPos.length-1] = nFileLength; aUc#,t;Qd  
} <&O*' <6C  
} a|4D6yUw|  
L>E{~yh  
B^zg#x#8  
//启动子线程 Lyn{Uag  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P_  8!Gp  
for(int i=0;i<nStartPos.length;i++) Z02EE-A  
{ xw_$1 S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WJa7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F:jtzy"  
nStartPos,nEndPos,i); 9xw"NcL  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dBovcc  
fileSplitterFetch.start(); H_x} -  
} V:P]Ved  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |S@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #8M^;4N >[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }|[0FP]v  
nEndPos = " + nFileLength); hy%5LV<(  
// fileSplitterFetch[nPos.length-1].start(); Vjo[rUW  
;1nXJ{jKw  
gae=+@z  
//等待子线程结束 ZPq.|6&  
//int count = 0; gV\Y>y4v  
//是否结束while循环 ZfVY:U:o>  
boolean breakWhile = false; 6|3 X*Orn  
ohJDu{V  
M}CxCEdDB]  
while(!bStop) !Yn#3c  
{ 6w m-uu  
write_nPos(); D/4]r@M2c  
Utility.sleep(500); I!1+#0SG  
breakWhile = true; iT O Y  
$XMpC{  
l=Pw yJ  
for(int i=0;i<nStartPos.length;i++) ,2^A<IwR  
{ JTBt=u{6^  
if(!fileSplitterFetch.bDownOver) <}8G1<QZ'.  
{ S0:Oep   
breakWhile = false; k&f/f  
break; ]F>#0Rdc  
} CAom4 Sp'  
} {TJBB/B1  
if(breakWhile) `D=`xSEYl  
break; sN?Rx}  
?YV#  K  
`T7TWv"M  
//count++; /4;A.r`;  
//if(count>4) I2SH j6 -  
// siteStop(); hDZyFRg  
} Ef ?|0Gm  
Lz-|M?(  
8d Fqwpw8  
System.err.println("文件下载结束!"); Y hmveV  
} WDV=]D/OE  
catch(Exception e){e.printStackTrace ();} ; 8eGf'  
} gV h&c 4  
pBv,,d`  
^>Z7."uGY  
//获得文件长度 N$C+le  
public long getFileSize() Eaxsg  
{ jAy2C&aP  
int nFileLength = -1; Q{'4,J-w  
try{ *vIP\NL?H  
URL url = new URL(siteInfoBean.getSSiteURL()); 2*#i/SE_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); PN<Vqt W  
httpConnection.setRequestProperty("User-Agent","NetFox"); EfpMzD7/(  
Y}t)!}p$r  
XIZN9/;  
int responseCode=httpConnection.getResponseCode(); *o:J 4'  
if(responseCode>=400) +_bxza(ma{  
{ JEWc{)4QD  
processErrorCode(responseCode); aot2F60J,  
return -2; //-2 represent access is error @V5i  
} @H~oOf  
`"yxmo*0  
Iu`S0#+  
String sHeader; L Yd:S  
5jwv!L<n  
bqA`oRb\  
for(int i=1;;i++) V mQ'  
{ mEi(DW)(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Qy[S~D_  
//Utility.log(in.readLine()); =&9c5"V&  
sHeader=httpConnection.getHeaderFieldKey(i); |pG0 .p4  
if(sHeader!=null) BOcD?rrZ0  
{ -KfK~P3PF  
if(sHeader.equals("Content-Length")) 4e AMb  
{ >b=."i  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ONDO xXs  
break; G%>[7]H  
} Wq5}LO)  
} oJ3(7Sz  
else +r;t]  
break; tCGx]\  
} &k)v/  
} FPF$~ sX  
catch(IOException e){e.printStackTrace ();} /3SEu(d!  
catch(Exception e){e.printStackTrace ();} N!wuBRWR  
_`^AgRE  
d6JW"  
Utility.log(nFileLength); qz3 Z'  
chKEGosbF  
"p|.[d  
return nFileLength; 8-k`"QI=  
} EQd<!)HZ  
1y wdcg  
19y,O0# _  
//保存下载信息(文件指针位置) 3#dz6+  
private void write_nPos() C#yRop_d]o  
{ FBB<1({A  
try{ G}+@C]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {I $iD  
output.writeInt(nStartPos.length); hwL`9.w  
for(int i=0;i<nStartPos.length;i++) Z2})n -  
{ [XDV-6KCE.  
// output.writeLong(nPos); ">3t+A  
output.writeLong(fileSplitterFetch.nStartPos); 1i~q~ O,  
output.writeLong(fileSplitterFetch.nEndPos); Z}>F V~4  
} _(8#  
output.close(); Yk?q\1  
} B&B:P  
catch(IOException e){e.printStackTrace ();} DQP!e6Of  
catch(Exception e){e.printStackTrace ();} W SxoGly  
} srAWet  
~TS!5Wiv  
8]b;l; W5  
//读取保存的下载信息(文件指针位置) \9` ~9#P  
private void read_nPos() ?a% F3B  
{ cHT\sJo`l  
try{ y {Bajil  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  +PADy8  
int nCount = input.readInt(); %Y=r5'6l  
nStartPos = new long[nCount]; |?Edk7`  
nEndPos = new long[nCount]; 8OV =;aM?{  
for(int i=0;i<nStartPos.length;i++) G6W|l2P!  
{ PLz+%L;{  
nStartPos = input.readLong(); K\fD';  
nEndPos = input.readLong(); Ay 4P_>^  
} ")vtS}Ekt  
input.close(); /!?Tv8TPp  
} ;|?_C8  
catch(IOException e){e.printStackTrace ();} @{_X@Wv4iV  
catch(Exception e){e.printStackTrace ();} 4;AQ12<[1  
} (?^F }]  
^p9V5o  
Tsb}\  
private void processErrorCode(int nErrorCode) N wNxO  
{ \7*|u  
System.err.println("Error Code : " + nErrorCode); UF-'(  
} ]a&riPh"  
zx2`0%Q  
K\;4;6 g  
//停止文件下载 7.ein:M|CB  
public void siteStop() V59!}kel1%  
{ Db*b"/]  
bStop = true; Y,}h{*9Kd  
for(int i=0;i<nStartPos.length;i++) cNmAr8^}  
fileSplitterFetch.splitterStop(); d-e/0F!  
U YJ>L  
+}?%w|8||s  
} Al8Dw)uG{  
} $ ~%Y}Xt*  
//负责部分文件的抓取 F {L#  
**FileSplitterFetch.java ocK4Nxs  
*/ s[h;9 I1w  
package NetFox; ftPhE)i  
^lZ7%6  
pKj:)6t"  
import java.io.*; " j?xgV  
import java.net.*; !> +Lre@  
%5KK#w "  
v@yqTZ  
public class FileSplitterFetch extends Thread { c!wRq4  
JBJ?|}5k4c  
u?MhK# Mr  
String sURL; //File URL Hf_ pe  
long nStartPos; //File Snippet Start Position sn^ 3xAF  
long nEndPos; //File Snippet End Position .|07IH/Di{  
int nThreadID; //Thread's ID VWK/(>TP  
boolean bDownOver = false; //Downing is over CL7 /J[TS  
boolean bStop = false; //Stop identical : fYfXm  
FileAccessI fileAccessI = null; //File Access interface &1^~G0 Rh\  
OGJrwl  
+MaEet  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException GeB&S!F  
{  ?f'`b<o  
this.sURL = sURL; \_R<Q?D+  
this.nStartPos = nStart; zZRLFfz<9  
this.nEndPos = nEnd; t B`"gC~  
nThreadID = id;  f-[.^/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ps\4k#aOv  
} R_GA`U\ {  
-X%t wy=  
U"Bge\6x=  
public void run() 8,vP']4r%  
{ fSVM[  
while(nStartPos < nEndPos && !bStop) UukY9n];]  
{ noa+h<vGb  
7SYe:^Dx  
2h*aWBLk  
try{ %P<fz1  
URL url = new URL(sURL); h,BPf5\S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $t"QLsk0  
httpConnection.setRequestProperty("User-Agent","NetFox"); +N+117m  
String sProperty = "bytes="+nStartPos+"-"; mr#.uhd.z  
httpConnection.setRequestProperty("RANGE",sProperty); Fec4#}|  
Utility.log(sProperty); ^z, B}Nz  
S["r @<  
ip{ b*@K  
InputStream input = httpConnection.getInputStream(); XfMUodV-OZ  
//logResponseHead(httpConnection); <'sm($.2  
%_p]6doF  
h]z8.k2n  
byte[] b = new byte[1024]; ZTfW_0   
int nRead; gYGoJH1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z4(\yx  
{ Yqo@ g2g  
nStartPos += fileAccessI.write(b,0,nRead); +cmi?~KS*  
//if(nThreadID == 1) _]Ob)RUVH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qyKR]%yzi  
} =+DhLH}8  
P2s\f;Dwr  
mA,{E-T  
Utility.log("Thread " + nThreadID + " is over!"); )*uotV  
bDownOver = true; ;WYz U`<g  
//nPos = fileAccessI.write (b,0,nRead); #sjGju"#_  
} $kmY[FWu?  
catch(Exception e){e.printStackTrace ();} l"X,[  
} &c&TQkx  
} y,n.(?!*  
xpuTh"ED  
eA?|X|  
//打印回应的头信息 T7/DH  
public void logResponseHead(HttpURLConnection con) Zj ^e8u=T  
{ \j wxW6>  
for(int i=1;;i++) p*YV*Arv  
{ DyZ6&*s$  
String header=con.getHeaderFieldKey(i); 0 .T5% _ /  
if(header!=null) 9X33{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ow5 VBw(  
Utility.log(header+" : "+con.getHeaderField(header)); UMD\n<+cG,  
else x 00'wY|  
break; FdEUZ[IT`{  
} %Q]thv:  
} ,g"JgX  
2dJE` XL  
Rx&.,gzj[  
public void splitterStop() A8S9HXL  
{ 3syA$0TZt  
bStop = true; a;~< iB;3"  
} OuWRLcJ!  
ScVbo3{m*T  
j!k$SDA-  
} Nqd9)WQ  
N,VI55J:y>  
!a!4^zqp  
/* {dE(.Z?]!#  
**FileAccess.java PGYx] r  
*//文件访问(定位,写) +tg${3ti_  
package NetFox; Rm$(X5x>o  
import java.io.*; >nvK{6xR:  
!>Q\Y`a,*  
^4\0, >  
public class FileAccessI implements Serializable{ e(b$LUV  
r6aIW8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2* T Ir  
RandomAccessFile oSavedFile; ('dbMH\O  
long nPos; Tl]yl$  
w6Mv%ZO_  
TMs Cl6dB  
public FileAccessI() throws IOException tBl (E  
{ f;,*P,K  
this("",0); 0blbf@XA  
} 9}fez)m:g0  
TA:#K  
gCVOm-*:  
public FileAccessI(String sName,long nPos) throws IOException $cm 9xW&  
{ F1M:"-bda  
oSavedFile = new RandomAccessFile(sName,"rw"); pbWjTI$  
this.nPos = nPos; jt*B0'Sa  
oSavedFile.seek(nPos); Q6 m.yds  
} m$pRA0s2`  
7<B-2g  
d:_;  
public synchronized int write(byte[] b,int nStart,int nLen) #@1(  
{ 4HGS  
int n = -1; ST g} Z  
try{ H5UF r,t  
oSavedFile.write(b,nStart,nLen); ^/x\HGrw  
n = nLen; Z^_zcH'  
} ,]n~j-X  
catch(IOException e) &Ll&A@yU  
{ G)Y,*.,  
e.printStackTrace (); uAoZ&8D6  
} n:1Ijh 1  
e VQ-?DK  
}*qj,8-9  
return n; pDvznpQ  
} AA=eWg  
pW>{7pXn  
PQh s^D  
} !<~cjgdx  
%@TC- xx  
P6'Se'f8  
/* qTMY]=(  
**SiteInfoBean.java ^7=7V0>,:  
*/ '^$+G0jv  
package NetFox; @^ m0>H  
fd>&RbUp  
P46Q3EE  
public class SiteInfoBean { ?gjx7TQ?  
v#X#F9C  
.`v%9-5v  
private String sSiteURL; //Site's URL M#m;jJqON  
private String sFilePath; //Saved File's Path N0NFgW;  
private String sFileName; //Saved File's Name YB2gxZ  
private int nSplitter; //Count of Splited Downloading File x#R6Ez7  
L2~'Z'q  
T"gk^.  
public SiteInfoBean() a1_o  
{//nSplitter的缺省值为5 6Q_A-X3hk  
//default value of nSplitter is 5 /Bh*MH  
this("","","",5); R*S:/s  
} $p$p C/:%  
iJmzVR+  
x.] tGS  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) HSAr6h  
{ %:;g|PC  
sSiteURL= sURL; K(d+t\ca  
sFilePath = sPath; zZ<*  
sFileName = sName; -%^'x&e  
this.nSplitter = nSpiltter; uhp.Yv@c  
MOnTp8   
mo(>SnS<  
} K' <[kh:cl  
_5x]BH6f  
3T4HX|rC  
public String getSSiteURL() n&?)gKL0g  
{ Dh?I   
return sSiteURL; Z,Us<du  
} S9r+Nsn  
v_WQ<G?  
U/|JAg #  
public void setSSiteURL(String value) $ &KkZ  
{ uKvdL "  
sSiteURL = value; X;l/D},.  
} kLU-4W5t  
DrC"M*$!  
['sNk[-C  
public String getSFilePath() yTZ o4c "  
{ cF8X  
return sFilePath; Q[K)Yd  
} K :~tZ  
Q>rr?L`  
cY kb3(  
public void setSFilePath(String value) >!a- "  
{ d%-/U!z?  
sFilePath = value; %d(= >  
} 8"ZS|^#  
/wt7KL- I  
\x]\W#C  
public String getSFileName()  P Je_qP  
{ L G5_\sY!  
return sFileName; .kPNWNrw  
} gt02Csdt  
;+6><O!G  
&);P|v`8  
public void setSFileName(String value) }*xjO/Ey  
{ "d0=uHd5\  
sFileName = value; ?# _{h  
} pi/0~ke4"  
-57~7 <N  
9:-7.^`P  
public int getNSplitter() }f?[m&<  
{ E]GbLU;TH  
return nSplitter; A~<!@`NjB  
} UXJblo#  
[wnp]'+!  
#9!7-!4pW  
public void setNSplitter(int nCount) : MjDcI~  
{ ov;^ev,(  
nSplitter = nCount; xy"'8uRi  
} $/;K<*O$  
} Yv@n$W`:  
WQ% O/  
vgD+Y   
/* GQ7uxdqWBQ  
**Utility.java ~?HK,`0h>  
*/ Y68A+ B.  
package NetFox; qIsf!1I?  
6L$KMYHE  
2b^Fz0 w4  
public class Utility {  -D'XxOI  
3]mprX'  
T]-MrnO  
public Utility() [xr^t1  
{ L/C~l3  
AD?XJ3  
M\{\WyeX  
} e(|Z<6  
-bHlFNRm  
//线程睡眠 /(51\RYkir  
public static void sleep(int nSecond) [X!w@d= i  
{ PS+~JwDUc  
try{ NLG\*mQ  
Thread.sleep(nSecond); Q!V:=d  
} tzIP4CR~F&  
catch(Exception e) 111A e *U  
{ 5:f!EMb  
e.printStackTrace (); L6{gwoZf3  
} F=1 #qo<?  
} 1(IZ,*i  
P@vUQ  
//日志 L-D4>+  
public static void log(String sMsg) PDuBf&/e  
{ % _E?3  
System.err.println(sMsg); ~o"=4q`>  
} 8{2  
~h;   
4dPTrBQ?  
public static void log(int sMsg) d9;&Y?fp  
{ &|#[.ti1  
System.err.println(sMsg); B#jnM~fJz  
} nk%v|ZxoFv  
} 52tc|j6~#  
O=RS</01!  
!uW*~u  
/* VYkh@j  
**TestMethod.java Z,E$4Z  
*/ <;PKec  
package NetFox; Z}uY%]  
)-Hs]D:  
}" vxYB!h3  
public class TestMethod { Qa )+Tv  
k !0O[U  
g}D)MlXRq  
public TestMethod() nco.j:  
{ ///xx/weblogic60b2_win.exe hoqZb<:  
try{ 4i)5=H  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Jp]?tlT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A%W]XEa<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )PP yJ@M  
fileFetch.start(); :QGo -,6-  
} tSJ#  
catch(Exception e){e.printStackTrace ();} W?.469yy  
7UMZs7L$  
0HoHu*+FX  
} S7f.^8  
e>Z&0lV:  
nWIZ0Nde'  
public static void main(String[] args) D`a6D  
{ }]o8}$&(  
new TestMethod(); Nbd4>M<  
} <lf692.3  
} $e7%>*?m  
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