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http断点续传简单实现(java)

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/* BT8)t.+pv  
**SiteFileFetch.java ;.sYE/ZVi  
*/ H%Vf$1/TF  
package NetFox; vA_,TS#Bo  
import java.io.*; mm +V*L{x  
import java.net.*; 5)XUT`;'){  
,P}7e)3  
hGV_K"~I0  
public class SiteFileFetch extends Thread { +W[f>3`VQ  
K1J |\!o  
<lIm==U<-  
SiteInfoBean siteInfoBean = null; //文件信息Bean _xh)]R  
long[] nStartPos; //开始位置 [q!]Ds" _  
long[] nEndPos; //结束位置 Gn^lF7yE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @br)m](@  
long nFileLength; //文件长度 vb>F)po1}  
boolean bFirst = true; //是否第一次取文件 sS ?A<D  
boolean bStop = false; //停止标志 d)!'5Zr M  
File tmpFile; //文件下载的临时信息 p1d%&e  
DataOutputStream output; //输出到文件的输出流 SJP3mq/^K  
}hg=#*  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) myX&Z F_9  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q >[>{N&\  
{ KO8{eT9d  
siteInfoBean = bean; co8R-AB  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); P!f0&W  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SzB<PP2  
if(tmpFile.exists ()) 'J} ?'{.  
{ 0 `7y Pq*  
bFirst = false; AA^K /y  
read_nPos(); 9;6)b 0=$  
} M| Gl&   
else hR|xUp  
{ \\:%++}J  
nStartPos = new long[bean.getNSplitter()]; 5`fUR/|[  
nEndPos = new long[bean.getNSplitter()]; zo@vuB.  
} vv,<#4d  
QAxy?m,'  
%XukiA+  
e< @$(w  
} KPz0;2}  
BZ.l[LMp  
${z#{c1  
public void run() MMKN^a"GA  
{ V1M|p!  
//获得文件长度 OW};i|  
//分割文件 meV Z_f/  
//实例FileSplitterFetch <B|b'XVH2  
//启动FileSplitterFetch线程 $Q#n'#c  
//等待子线程返回 rucw{) _  
try{ >e/>@ J*  
if(bFirst) vd#)+  
{ 0/ 33Z Oc  
nFileLength = getFileSize(); 8Pd9&/Y  
if(nFileLength == -1) HRE?uBkjf  
{ dh6kj-^;Cf  
System.err.println("File Length is not known!"); &AxtSIpucP  
} SW}Rkr\e  
else if(nFileLength == -2) /_J{JGp9  
{ rWJ5C\R  
System.err.println("File is not access!"); ",aNYJR>*!  
} `]l` t"x  
else B<BS^waU  
{ 0/DO"pnL@  
for(int i=0;i<nStartPos.length;i++) Ng;?hTw  
{ 6X A(<1P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =gSc{ i|  
}  D~"a"  
for(int i=0;i<nEndPos.length-1;i++) VOr: G85*s  
{ ~tfd9,t  
nEndPos = nStartPos[i+1]; 3s%DF,  
} ef7 U7   
nEndPos[nEndPos.length-1] = nFileLength; "aKlvK:77  
} FY Flh^}  
} >%`SXB& 9  
N}nE9z5  
O&/n BHu\  
//启动子线程 BhAT@%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2 ^"j]g>mj  
for(int i=0;i<nStartPos.length;i++) ,(h -  
{ -?#iPvk6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o9| OL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z}0{FwW"4  
nStartPos,nEndPos,i); M .6BFC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qZ>_{b0f  
fileSplitterFetch.start(); -!7Z  
} HTiLA%%6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {9|*au(K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;|XX^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", MXl_{8  
nEndPos = " + nFileLength); ML|?H1m>  
// fileSplitterFetch[nPos.length-1].start(); UZFs ]z!,k  
O95gdxc  
i^:#*Q-co  
//等待子线程结束 a8)2I~j  
//int count = 0; ]Zh$9YK  
//是否结束while循环 M __S)  
boolean breakWhile = false; FsOJmWZ  
w3 vZ}1|  
1l)j(,Zd*  
while(!bStop) 7&P70DO  
{ yy/'B:g  
write_nPos(); Jjj;v2uSK  
Utility.sleep(500); Ppl :_Of  
breakWhile = true; j|[$P4w}U  
3r[F1z2B  
V[%IU'{:  
for(int i=0;i<nStartPos.length;i++) 6`'g ${U  
{ Q'^'G>MBJ  
if(!fileSplitterFetch.bDownOver) aJ=)5%$6kc  
{ q0ab]g+  
breakWhile = false; cyd&bxPgj+  
break; C=Fu1Hpb  
} k1g-%DB  
} l%Ke>9C  
if(breakWhile) R*cef  
break; W.{+0xx  
_0u=}tc  
JT<JS6vw#  
//count++; 'tkQz  
//if(count>4) MaPhG<?  
// siteStop(); @6~m&$R/  
} ;,]4A{|  
k9H}nP$F  
qB@N|Bb  
System.err.println("文件下载结束!"); $;=^|I4E  
} ktfxb <%  
catch(Exception e){e.printStackTrace ();} J3oUtu  
} Ux^ue9  
{I0!q"sF  
&.2% p  
//获得文件长度 5G'2 Wby'#  
public long getFileSize() a(fiW%eFb  
{ Vr& GsT  
int nFileLength = -1; >mvE[iXRG?  
try{ .%J<zqk-  
URL url = new URL(siteInfoBean.getSSiteURL()); v0\M$@N[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E*T6kp^b  
httpConnection.setRequestProperty("User-Agent","NetFox"); DsxNg  
|*ZM{$  
v0&DD&mp  
int responseCode=httpConnection.getResponseCode(); :0%[u(  
if(responseCode>=400) dj] O  
{ ^Ar1V!PFk  
processErrorCode(responseCode); D` cy.},L  
return -2; //-2 represent access is error 5IzCQqOPgX  
} T,/<'cl"  
;^E\zs  
l_04b];  
String sHeader; ;mD!8<~z.  
KU/QEeqbrp  
P^Og(F8;  
for(int i=1;;i++) %sZ3Gpi  
{ 8N j}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _(=g[=Mer  
//Utility.log(in.readLine()); H9BqE+  
sHeader=httpConnection.getHeaderFieldKey(i); ]o'dr r  
if(sHeader!=null) G]xN#O;  
{ p[|V7K'Z  
if(sHeader.equals("Content-Length")) >#S}J LZ  
{ 7|Wst)_~j  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]3]B$  
break; .8'uIA{_2  
} 32j#kJW  
} 9ec#'i=  
else 5xUZeLj  
break; ey<z#Q5+  
} 2Nm{.Y  
} 2C"i2/NH'  
catch(IOException e){e.printStackTrace ();} c?c"|.-<p  
catch(Exception e){e.printStackTrace ();} x)%"i)  
*<{hLf  
&Nr+- $  
Utility.log(nFileLength); 1p/_U?H:|  
d"3x11|  
$*XTX?,'  
return nFileLength; S:g6z'e1  
} L1k  
l%i*.b(  
-c0*  
//保存下载信息(文件指针位置) e&(Wn2)o  
private void write_nPos() KF#qz2S  
{ rnMi >?  
try{ +WR'\15u   
output = new DataOutputStream(new FileOutputStream(tmpFile)); :zfMRg  
output.writeInt(nStartPos.length); RcR-sbR  
for(int i=0;i<nStartPos.length;i++) D&N3LH  
{ vgNrHq&2q  
// output.writeLong(nPos); h^WMv *2  
output.writeLong(fileSplitterFetch.nStartPos); ]w-W  
output.writeLong(fileSplitterFetch.nEndPos); +-V4:@  
} mMu+MXTk<  
output.close(); IK4(r /  
} F2n4#b  
catch(IOException e){e.printStackTrace ();} 6khm@}}  
catch(Exception e){e.printStackTrace ();} W8]?dL}|  
} Qe9}%k6@E  
7<8'7<X  
j\B taC  
//读取保存的下载信息(文件指针位置) `X&d:!}F  
private void read_nPos() -@'RYY=  
{ %vG;'_gM B  
try{ YD~(l-?"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &d!ASa  
int nCount = input.readInt(); >N~jlr|  
nStartPos = new long[nCount]; pZc`!f"  
nEndPos = new long[nCount]; PCBV6Y7r  
for(int i=0;i<nStartPos.length;i++) m60hTJ?N)  
{ ^6CPC@B1  
nStartPos = input.readLong(); axXR-5c  
nEndPos = input.readLong(); ;'!h(H  
} I[ 06R  
input.close(); kMa|V0  
} ^}z:FI   
catch(IOException e){e.printStackTrace ();} /Vv)00  
catch(Exception e){e.printStackTrace ();} ~( rZ)  
} {@" F/G+  
g'-hSV/@}@  
tM:$H6m/(  
private void processErrorCode(int nErrorCode) S =sL:FC  
{ ZM=eiJZ  
System.err.println("Error Code : " + nErrorCode); v,3 }YDu  
} oO;< $wx2t  
pBu}c<  
~dsx|G?p  
//停止文件下载 [H`5mY@  
public void siteStop() ${t$:0R,h  
{ ]jmZ5h#[  
bStop = true; ,mD$h?g  
for(int i=0;i<nStartPos.length;i++) PDh!B _+  
fileSplitterFetch.splitterStop(); [S.zWPX9{  
p5nrPL  
tKi ^0vE8  
} <V8=*n"mR  
} qV$0 ";d  
//负责部分文件的抓取 %we! J%'Y]  
**FileSplitterFetch.java ;O .;i,#Z  
*/ =NRiro  
package NetFox; Tkh?F5l  
dTU`@!f  
(b.Mtd  
import java.io.*; lqoVfj'6M  
import java.net.*; w-wJhc|  
(Y?}'?  
w/fiNY5FZ  
public class FileSplitterFetch extends Thread { LA,G>#?H  
Q#4OgNt  
qyBo|AQ5  
String sURL; //File URL * ^\u%Ir"  
long nStartPos; //File Snippet Start Position Vgj[m4l  
long nEndPos; //File Snippet End Position 1!ijRr  
int nThreadID; //Thread's ID aU] nh. a  
boolean bDownOver = false; //Downing is over c 8|&Q  
boolean bStop = false; //Stop identical 0gKSjTqo  
FileAccessI fileAccessI = null; //File Access interface ~Z97L  
R"71)ob4  
vrsOA@ee3H  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException pD6a+B\;k  
{ '&y+,2?;Y[  
this.sURL = sURL; rAu@`H?  
this.nStartPos = nStart; \#'m([<e  
this.nEndPos = nEnd; hl+ T  
nThreadID = id; 1~*JenV-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wA%,_s/U  
} dM5N1$1,  
QnH~' k  
I9cZZ`vs  
public void run() ~0{F,R.$  
{ vqwSOh|P9  
while(nStartPos < nEndPos && !bStop) #X<s_.7DJ  
{ )-LS n  
ZV:0:k.x  
(ZK(ODn)i  
try{ Biy$p6  
URL url = new URL(sURL); `lE8dwL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L?hWH0^3  
httpConnection.setRequestProperty("User-Agent","NetFox"); }RkD7  
String sProperty = "bytes="+nStartPos+"-"; x#tP)5n?s*  
httpConnection.setRequestProperty("RANGE",sProperty); &PEw8: TX  
Utility.log(sProperty); eJZt&|7N  
)G$0:-J-  
M7AUY#)  
InputStream input = httpConnection.getInputStream(); ::k/hP9.^  
//logResponseHead(httpConnection); sHMZ'9b  
H|B4.z  
-<n]Sv;V  
byte[] b = new byte[1024]; '.tg\]|  
int nRead; H?'t>JX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) U\tujK1  
{ )u5+<OG}=  
nStartPos += fileAccessI.write(b,0,nRead); PPj0LFA  
//if(nThreadID == 1) f.u+({"ql  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^ Hv4t   
} m[?gN&%nc  
Vg? 1&8>  
8Jf4" ;  
Utility.log("Thread " + nThreadID + " is over!"); -$kA WP8P4  
bDownOver = true; Hz3KoO &  
//nPos = fileAccessI.write (b,0,nRead); *8xMe  
} 1"} u51  
catch(Exception e){e.printStackTrace ();} 8|\?imOp\[  
} t9m08K:Y  
} H5p&dNO  
g=n /w  
=xsTVT;sj  
//打印回应的头信息 8u#2M8.5E  
public void logResponseHead(HttpURLConnection con) [e`6gGO  
{ THDyb9_g  
for(int i=1;;i++) EEO)b_(  
{ U>kL|X3 V  
String header=con.getHeaderFieldKey(i); *`wgqin  
if(header!=null) A;C)#Q/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); G8!* &vR/  
Utility.log(header+" : "+con.getHeaderField(header)); c7(Lk"G8  
else YST{ h{  
break; yixAG^<  
} G![JRJxQ  
} yj C@  
:/'oh]T|  
+HNM$yp  
public void splitterStop() $/;;}|hqi  
{ InR/g@n+D1  
bStop = true; "E )0)A3=  
} !%%(o%bi~  
K-drN)o  
+OC~y:  
} Q !G^CG  
6'1m3<G_  
XhG3Of-6  
/* B1Cu?k);.  
**FileAccess.java %.VFj7J  
*//文件访问(定位,写) ?mJ&zf|B8  
package NetFox; h1.<\GO  
import java.io.*; ORP-@-dap  
^26}j uQ  
dw]jF=u  
public class FileAccessI implements Serializable{ 1=Nh<FuQ  
s+OXT4>+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 VgyY7INx9  
RandomAccessFile oSavedFile; x l4A<  
long nPos; M|xs>+r*  
bL]NSD  
wPrqFpf  
public FileAccessI() throws IOException XPQY*.l&.  
{ o6T'U#7P  
this("",0); ;o-c.-!F  
} Th>ff)~ e  
]XhX aoqL  
@UCr`>  
public FileAccessI(String sName,long nPos) throws IOException .bvEE  
{ /@QPJ~%8Ud  
oSavedFile = new RandomAccessFile(sName,"rw"); @m+2e C77  
this.nPos = nPos; >#~>!cv6D  
oSavedFile.seek(nPos); JOFQyhY0>m  
} s2*~n_B  
)LDBvpJyQ  
#4BwYj(Sl  
public synchronized int write(byte[] b,int nStart,int nLen) AMf{E  
{ qe<aJn  
int n = -1; j;SK{Oq  
try{ ykat0iqo  
oSavedFile.write(b,nStart,nLen); _-5|"oJ  
n = nLen; 5~GH*!h%;  
} BOdd~f%&tn  
catch(IOException e) Z b}U 4  
{ !THa?U;  
e.printStackTrace (); ~ NZC0&  
} :^H2D=z@  
(utk)  
<kOdd)X  
return n; 7*\Cf qrU  
} 5/YGu=,  
!hWS%m@  
h h7unHt-  
} *!m(oP  
7 tQ?av  
dwJnPJ=z  
/* n4InZ!)  
**SiteInfoBean.java / ?Hq  
*/ Aa4 DJ  
package NetFox; Xb2.t^ ]f  
>0E3Em<(}l  
R@~=z5X( Q  
public class SiteInfoBean { s((c@)M  
B]u!BBjC  
+; / s0  
private String sSiteURL; //Site's URL _qa9wK/  
private String sFilePath; //Saved File's Path 7Fzj&!>ti  
private String sFileName; //Saved File's Name `G:I|=#w  
private int nSplitter; //Count of Splited Downloading File [P*zm8b  
{4eI} p<  
~@mNR^W-W  
public SiteInfoBean() EslHml#  
{//nSplitter的缺省值为5 "</A) y&  
//default value of nSplitter is 5 @Nn'G{8OG  
this("","","",5); *I.eCMDa  
} EGVS8YP>h  
%l[]n;*$  
>S>B tR l  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) lk.Mc6)  
{ moRo>bvN~  
sSiteURL= sURL; MO%+rf0~w  
sFilePath = sPath; \+j:d9?  
sFileName = sName; 5Nl?Km~  
this.nSplitter = nSpiltter; '*D>/hn|:]  
Q zp!)i  
$Y M(NC  
} ipyc(u6Z5  
xnxNc5$oE  
e$7KMH=  
public String getSSiteURL() Je4hQJ<h  
{ +GncQs y  
return sSiteURL; -"rANP-UI  
} .d6b ?t  
&v#pS!UOj  
Va[t'%~&zR  
public void setSSiteURL(String value) Y`."=8R~  
{ ^l<!:SS  
sSiteURL = value; T: SqENV  
} DMOP*;Uk  
3$S~!fh  
.03Rp5+v  
public String getSFilePath() C3'?E<F  
{ a$\ Bt_  
return sFilePath; 1Tr%lO5?6  
} "'C5B>qO  
>pp#>{}  
c dWg_WBC  
public void setSFilePath(String value) s bd$.6 |&  
{ qeb}~FL"o  
sFilePath = value; G[6i\Et   
} T;]Ob3(BpW  
eV~"T2!Sb  
(\'$$  
public String getSFileName() n5z|@I`S_  
{ 6AoKuT;  
return sFileName; \}~71y}  
} [ . }Uzx  
K>C@oE[W  
m2P&DdN[  
public void setSFileName(String value) @1xIph<z  
{ L6#4A3yh  
sFileName = value; &;~?\>?I  
} 3.1%L"r[)  
fz A Fn$[  
_z J /z  
public int getNSplitter() e)N< r  
{ :K5?&kT  
return nSplitter; +prUau*  
} ns *:mGh  
MkhD*\D /  
)+DDIq  
public void setNSplitter(int nCount) w!z* ?k=Da  
{ X%iJPJLza  
nSplitter = nCount; K7@|2;e  
} JPHM+3v  
} =z]rZSq*o  
&H P g>  
|sY  
/* )0DgFA6k_  
**Utility.java q#SEtyJL  
*/ 3=^)=yOd  
package NetFox; bWSc&/ 9y  
BzS\p3&  
(> _Lb  
public class Utility { !dUdz7  
#C~ </R%  
K&zW+C b  
public Utility() KVr9kcs  
{ ijUu{PG`X  
SM%/pu;  
,RM8D)m\  
} ~( 0bqt3c  
4w#2m>.  
//线程睡眠 P3n#s2o6y  
public static void sleep(int nSecond) ij! ],  
{ Jm#p!G+  
try{ LokH4A17U  
Thread.sleep(nSecond); ?qi~8.<w  
} vm{8x o  
catch(Exception e) wu><a!3`=o  
{ 4c95G^dZ  
e.printStackTrace (); KO%$  
} .@%L8_sMR  
} 1G.?Y3DC<  
09 trFj$L  
//日志 [z ]P5  
public static void log(String sMsg) lS#: u-k  
{ sW'_K.z  
System.err.println(sMsg); x,]x>Up  
} rMHh!)^#W  
CLk,]kA'r  
L\UGC%]9  
public static void log(int sMsg) HfgTc h  
{ ZSW@,Ti  
System.err.println(sMsg); xr]bH.>  
} 6W{Nw<  
} n|6G\99l+M  
\#LDX,=  
rks"y&&Nc  
/* s~2o<#  
**TestMethod.java _z8"r&  
*/ +])<}S!M  
package NetFox; 8<mloM-4  
H#D:'B j29  
IN<nZ?D#  
public class TestMethod { S{N4[U?V>  
\8!CKnfs  
2uN3:_w  
public TestMethod() y6tqemz  
{ ///xx/weblogic60b2_win.exe m$^5{qpg  
try{ >r7PK45.K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f S/:OnH  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O/FI>RT\H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `h'l"3l  
fileFetch.start(); `^[Tu 1  
} /;+\6(+X  
catch(Exception e){e.printStackTrace ();} pZopdEFDK|  
gC(S(osF  
}T(=tfv@  
} iKV|~7nwO  
;$zvm`|:  
{l!{b1KJ  
public static void main(String[] args) H`fJ< So?  
{ ;22?-F^  
new TestMethod(); hZ452W  
} bRyxP2  
} _b&26!gl  
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