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http断点续传简单实现(java)

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/* Xg,0/P~  
**SiteFileFetch.java ]cn/(U`  
*/ 7U&5^s )J  
package NetFox; ~5FS|[1L  
import java.io.*; iJ,M-GHK  
import java.net.*; hyJ ded&D  
Sjw2 j#Q  
J 5Wz4`'  
public class SiteFileFetch extends Thread { &/sGh0  
P{"  WlJ  
}A^ 1q5  
SiteInfoBean siteInfoBean = null; //文件信息Bean /_ $~rW  
long[] nStartPos; //开始位置 1P(%9  
long[] nEndPos; //结束位置 #L_@s d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 17WNJ  
long nFileLength; //文件长度 4kWg>F3  
boolean bFirst = true; //是否第一次取文件 _=o1?R  
boolean bStop = false; //停止标志 - P\S>G.  
File tmpFile; //文件下载的临时信息 0q:(-z\S4  
DataOutputStream output; //输出到文件的输出流 ;%BhhmR)[  
hO^&0?  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 6W)xj6<@  
public SiteFileFetch(SiteInfoBean bean) throws IOException ` %FIgE^  
{ U(rr vNt:t  
siteInfoBean = bean;  ]# Y|   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V<7R_}^_7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =#OHxM  
if(tmpFile.exists ()) Bv2z4D4f+  
{ zWF 5m )-  
bFirst = false; B@ZqJw9J[  
read_nPos(); C>.]Bvg  
} u&1j>`~qJ  
else OT-n\sL$  
{ :*mA,2s  
nStartPos = new long[bean.getNSplitter()]; cEDDO&u  
nEndPos = new long[bean.getNSplitter()]; a9yIV5_N  
} l@,);w=_P  
X)`(nj  
Iq4Kgc  
s,eld@  
} &,W_#l{  
M[:O(  
Gl?P.BCW.&  
public void run() PWf{aHsr  
{ anHBy SI3  
//获得文件长度 PY^^^01P  
//分割文件 1_Dn?G^H  
//实例FileSplitterFetch O, bfdc[g4  
//启动FileSplitterFetch线程 Q3B'-BZe  
//等待子线程返回 (P E# Y(  
try{ qPFG+~\c  
if(bFirst) ?RgU6/2  
{ 5;3c<  
nFileLength = getFileSize(); ATYQ6E[{MV  
if(nFileLength == -1) Nw9-pQ  
{ )'BJ4[aq\  
System.err.println("File Length is not known!"); ka?IX9t\  
} pm'@2dT  
else if(nFileLength == -2) Bq$e|t)'  
{ GibggOj2Q,  
System.err.println("File is not access!"); `-72>F;T  
} :GwSs'$O  
else `nd#< w>  
{ ,<uiitOo  
for(int i=0;i<nStartPos.length;i++) %{N$1ht^  
{ < "L){$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R,d70w (_  
} L}e"nzTE6I  
for(int i=0;i<nEndPos.length-1;i++) `}k&HRn  
{ 1jUhG2y  
nEndPos = nStartPos[i+1]; E<zT  
} ~uhyROO,G"  
nEndPos[nEndPos.length-1] = nFileLength; Ckl7rpY+  
} 5UrXVdP  
} Ie^Dn!0S  
G*vpf~q?  
LH3N}J({  
//启动子线程 1WUFk?p  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %vf2||a$BS  
for(int i=0;i<nStartPos.length;i++) |"Xi%CQ2  
{ wZ]BY;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m' Ekp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), o-Q]Dk1W  
nStartPos,nEndPos,i); -CU7u=*b  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [}9XHhY1O=  
fileSplitterFetch.start(); I |<+'G  
} ctc`^#q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P xP?hk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  :kp  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", :]u}x Dv3  
nEndPos = " + nFileLength); hdsgOu  
// fileSplitterFetch[nPos.length-1].start(); AjL?Qh4  
X>6 ~{3  
MUCJ/GF*  
//等待子线程结束 ZyS;+"  
//int count = 0; aCUV[CPw  
//是否结束while循环  0'V-  
boolean breakWhile = false; SQ^^1.V&/Y  
G>q{~HE1  
O)U$Ef  
while(!bStop) `jUS{ 3^  
{ o%4&1^ Vg  
write_nPos(); (}~eD  
Utility.sleep(500); [KimY  
breakWhile = true; Kc9mI>uH  
t'=~"?T/o  
e&H<lT  
for(int i=0;i<nStartPos.length;i++) j quSR=  
{ -9H!j4]T?  
if(!fileSplitterFetch.bDownOver) _~w V{ yp  
{ q*RaX 4V  
breakWhile = false; =qS^Wz.  
break; 3f:1D=f  
} ];b!*Z  
} B GEJiLH  
if(breakWhile) LKf5r,C  
break; wWOT*R_  
Z z; <P  
-EkDG]my  
//count++; ,I2re G  
//if(count>4) m|ERf2-  
// siteStop(); T24#gF~  
} S)'q:`tZo  
QnP?;  
vZ nO  
System.err.println("文件下载结束!"); 8v)~J}[Bz  
} Y3MR:{}  
catch(Exception e){e.printStackTrace ();} S^Wqa:;  
} C(t6;&H  
R 6yvpH  
3 ?|; on  
//获得文件长度 S9"y@F <  
public long getFileSize() : 7DVc&0  
{ Etr8lm E  
int nFileLength = -1; E'BH7JV  
try{ 4|Gs(^nU  
URL url = new URL(siteInfoBean.getSSiteURL()); <C.$Db&9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J|2Hqd  
httpConnection.setRequestProperty("User-Agent","NetFox"); W'2-3J  
l#vw L15  
D 917[ <$  
int responseCode=httpConnection.getResponseCode(); v$Y1+Ep9  
if(responseCode>=400) lRATrp#T  
{ 8apKp?~yW  
processErrorCode(responseCode); Tk#&Ux{ZJ  
return -2; //-2 represent access is error ^a#&wW  
} K<7T}XzU$  
!qGx(D{\  
}zS&H-8K  
String sHeader; Z=t#*"J  
&CeF^   
v"('_!  
for(int i=1;;i++) zm3MOH^a  
{ z.9FDQLp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cA*X$j6  
//Utility.log(in.readLine()); soVZz3F  
sHeader=httpConnection.getHeaderFieldKey(i); qT>& v_<  
if(sHeader!=null) .' 2gJ"?,  
{ d t0E0i  
if(sHeader.equals("Content-Length")) e}O-I  
{ BM$tywC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M>H^<N}'A  
break; xE-`Bb  
} 'S D|ObBY  
} er7/BE&  
else Y./}zCT  
break; ]-Y]Q%A4  
} 4C9"Q,o%&  
} ![hhPYmV  
catch(IOException e){e.printStackTrace ();} }}bi#G:R+  
catch(Exception e){e.printStackTrace ();} H6CGc0NS+  
;s B:s9M  
f`]E]5?  
Utility.log(nFileLength); *2C79hi1  
qjEWk."  
!2M[  
return nFileLength; ,lS-;.  
} #.L0]Uqcp  
[ma#8p)  
oS|~\,p"  
//保存下载信息(文件指针位置) Q2pboZ86  
private void write_nPos() uZ?CVluP  
{ #~-&&S4a.J  
try{ ^8*SCM_A  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )Gp\_(9fc  
output.writeInt(nStartPos.length); M"l rwun^  
for(int i=0;i<nStartPos.length;i++) /(pD^D  
{ >rS<!e%  
// output.writeLong(nPos); Rpd/9x.)&  
output.writeLong(fileSplitterFetch.nStartPos); ;)pV[3[  
output.writeLong(fileSplitterFetch.nEndPos); {1U*: @j  
}  glX2L ~  
output.close(); =X5&au o  
} ^PR,TR.  
catch(IOException e){e.printStackTrace ();} f4y;K>u7p  
catch(Exception e){e.printStackTrace ();} 3udIe$.Q  
} >N1]h'q>  
m7eIhmP  
N4DDH^h  
//读取保存的下载信息(文件指针位置) $$f$$  
private void read_nPos() KXfW&d(Pk  
{ A.x}%v,E  
try{ Zt0%E <C{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 207oE O]  
int nCount = input.readInt(); iT9Ex9RL  
nStartPos = new long[nCount]; EAXU{dRV  
nEndPos = new long[nCount]; B(Q.a&w45t  
for(int i=0;i<nStartPos.length;i++) &u\z T P  
{  `e=n( D  
nStartPos = input.readLong(); UKQ&TV}0  
nEndPos = input.readLong(); TZyQOjUu  
}  n(xlad  
input.close(); SWd[iD  
} LVl0:!>~  
catch(IOException e){e.printStackTrace ();} &B0&183  
catch(Exception e){e.printStackTrace ();} Y]Vc}-a(h  
} J15T!_AW<  
>Io7h#[u  
Y8{1?LO  
private void processErrorCode(int nErrorCode) #LgoKiP!Y  
{ gH)B` @  
System.err.println("Error Code : " + nErrorCode); j6(IF5MqP  
} B2WX#/lgd  
% peb{i  
<OfzE5  
//停止文件下载 { (,vm}iFL  
public void siteStop() A0u:Fm{E  
{ IqKXFORiNI  
bStop = true; gc[J.[  
for(int i=0;i<nStartPos.length;i++) ;]x5;b9`  
fileSplitterFetch.splitterStop(); pAmI ](  
V46[whL%r  
DC7}Xly(  
} "FvlZRfXj  
} >*xzSd? \  
//负责部分文件的抓取 q\Kdu5x{  
**FileSplitterFetch.java =PM#eu  
*/ F|{?GV%hF  
package NetFox; IOqyqt'  
Jo+C!kc  
l #z`4<  
import java.io.*; }"H900WE|  
import java.net.*; Lb 4!N` l  
1M+!cX  
Bd[Gsns  
public class FileSplitterFetch extends Thread { jhM|gV&  
8}T3Fig,q  
R)Fl@ Tn  
String sURL; //File URL L-gF$it\*b  
long nStartPos; //File Snippet Start Position ^- Ji]5~  
long nEndPos; //File Snippet End Position ^IkMRlJh%  
int nThreadID; //Thread's ID qrYeh`Mv  
boolean bDownOver = false; //Downing is over wuQkeWxJ  
boolean bStop = false; //Stop identical \Da$bJ  
FileAccessI fileAccessI = null; //File Access interface 2GS2,  
tRCd(Z,WY  
_lqAxWH  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException x%&V!L  
{ K\Q 1/})  
this.sURL = sURL; T/5U lW|\  
this.nStartPos = nStart; a9-;8`fCR  
this.nEndPos = nEnd; a9Rh  
nThreadID = id; p?nVPTh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 kk#d-! $[  
} wX;NU4)n  
TA7w:<  
iJeT+}  
public void run() oGJI3Oh  
{ &>{L"{  
while(nStartPos < nEndPos && !bStop) e~dU "  
{ 2&#iHv  
'9XwUQx  
`#F>?g$2  
try{ 4R6 .GO  
URL url = new URL(sURL); |lY8u~%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ccAEN  
httpConnection.setRequestProperty("User-Agent","NetFox"); k2;yl _7  
String sProperty = "bytes="+nStartPos+"-"; u}_q'=<\  
httpConnection.setRequestProperty("RANGE",sProperty); P6rL;_~e  
Utility.log(sProperty); Jo]g{GX[  
p9J(,}  
\W!<xE  
InputStream input = httpConnection.getInputStream(); d[de5Xra  
//logResponseHead(httpConnection); ;d:7\  
mi?Fy0\  
&#.&xc2sRZ  
byte[] b = new byte[1024]; uIBV1Qz  
int nRead; o? =u#=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5Jp>2d  
{ #=rI[KI  
nStartPos += fileAccessI.write(b,0,nRead); WObfHAp.  
//if(nThreadID == 1) gnt[l0m  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U*t `hn-xs  
} GS@ wG  
?(N(8)G1  
^z1WPI  
Utility.log("Thread " + nThreadID + " is over!"); 3? "GH1e  
bDownOver = true; m`t7-kiZ  
//nPos = fileAccessI.write (b,0,nRead); ;(A'XA4 6N  
} .KV?;{~q@  
catch(Exception e){e.printStackTrace ();} KT}}=st%  
} 'tc$#f^:  
} 1'=brc YR  
~ lS3+H  
<W1!n$V ]  
//打印回应的头信息 71eD~fNdx  
public void logResponseHead(HttpURLConnection con) EC7o 3LoND  
{ g.'4uqU  
for(int i=1;;i++) /D~:Ufw  
{ VrDvd  
String header=con.getHeaderFieldKey(i); U i;o/Z3  
if(header!=null) Q"\[ICu!,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'RhMzPmY>  
Utility.log(header+" : "+con.getHeaderField(header)); v^pE= f*/  
else /3fo=7G6  
break; $W)FpN;CW/  
} [}Nfs3IlBw  
} vwg\qKqSM  
;2$^=:8  
FD8aO?wvg  
public void splitterStop() @|M10r9E  
{ -?ip?[Z  
bStop = true; t+pI<c^]y  
} E: %%Dm  
5s0H4?S  
I6UZ_H'E  
} St?vd+(>  
Pai{?<zGi  
,ihTEw,t(  
/*  ,}bC  
**FileAccess.java 4Hu.o7  
*//文件访问(定位,写) +Q{jV^IT9  
package NetFox; yjr!8L:m  
import java.io.*; F3?v&  
";Lpf]<  
Eh JYdO[e  
public class FileAccessI implements Serializable{ Ly3^zF W  
t4nAy)I)P  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6$IAm#  
RandomAccessFile oSavedFile; \wM r[_LW  
long nPos; =oSv=xY  
G.9?ApG9  
d6_ CsqV  
public FileAccessI() throws IOException #T+%$q [:  
{ *@/! h2  
this("",0); ?g!py[CrE  
} m'Wz0b^BO  
G|.>p<q   
o-R;EbL  
public FileAccessI(String sName,long nPos) throws IOException ,Xao{o(  
{ T*z >A  
oSavedFile = new RandomAccessFile(sName,"rw"); '9-8_;  
this.nPos = nPos; NoV2<m$  
oSavedFile.seek(nPos); IGVNX2  
} 2 rne=L  
T-eeYw?Yf  
]^"*Fdn  
public synchronized int write(byte[] b,int nStart,int nLen) gVk_<;s  
{ m"NZ;*d'  
int n = -1; &c0U\G|j  
try{ 8hGp?Ihu  
oSavedFile.write(b,nStart,nLen); /9;)zI  
n = nLen; ? %F*{3IP  
} ?~;G)5  
catch(IOException e) rj<r6  
{ GKSfr8US4  
e.printStackTrace (); N^B YNqr  
} 4$@)yZ  
AW1691Q  
Zn|vT&:Hg  
return n; hQvSh\p  
} 7$k[cL1  
?u"MsnCXYn  
sd xl@  
} V07e29w  
fHdPav f,S  
L@XhgQ  
/* r1]shb%J?  
**SiteInfoBean.java 6MqJy6  
*/ Rcfh*"k  
package NetFox; E$T)N U\  
?dY}xE  
}hv>LL  
public class SiteInfoBean { PSNfh7g  
aHvTbpJ  
g`k_o<'JC  
private String sSiteURL; //Site's URL I MpEp}7  
private String sFilePath; //Saved File's Path +h.$ <=  
private String sFileName; //Saved File's Name G$<FQDvs  
private int nSplitter; //Count of Splited Downloading File LcI,Dy|P  
=rFgOdj  
17 Hdj  
public SiteInfoBean() i!@L`h!rw  
{//nSplitter的缺省值为5 icOh/G=N;  
//default value of nSplitter is 5 ;Z\jX[H  
this("","","",5); WgF Xv@Jjt  
} >LRt,.hy6  
$fR[zBxA  
2&S*> (  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) CXwDG_e  
{ QK)"-y}"g  
sSiteURL= sURL; Pfj{TT.#L  
sFilePath = sPath; v,#*%Gn`%  
sFileName = sName; -}_-#L!Q  
this.nSplitter = nSpiltter;  A M8bem~  
hosw :%  
GSj04-T"  
} ]{;=<t6  
C(qqGK{  
qc;9{$?xV  
public String getSSiteURL() 481J=8H  
{ n@r'b{2;l  
return sSiteURL; #Y6'Q8g f  
} B/hL  
:yO.Te F  
zcnp?%  
public void setSSiteURL(String value) {L^b['h@  
{ \x\_I1|  
sSiteURL = value; H}5zKv.T  
} _7Z|=)  
xrd@GTaI  
]"Z*Hq z  
public String getSFilePath() G41 gil6k  
{ ;dgxeP;mp  
return sFilePath; \} [{q  
} 7)aitDD  
Yz4)Q1  
+c$]Q-(  
public void setSFilePath(String value) L>VZ-j  
{ huVw+vAA  
sFilePath = value; Y?G\@ 6  
} GZXBzZ}  
 &0! f_  
t-7^deG'/n  
public String getSFileName() KKpO<TO  
{ /3`#ldb%}  
return sFileName; Nb;xJSlox  
} U"\$k&  
A<-Prvryt  
`D)ay  
public void setSFileName(String value) V8AF;1c?-'  
{ "#Ov!t  
sFileName = value; qOOF]L9r%u  
} 1haNca_6,  
1UG5Q-  
n-iy;L^b  
public int getNSplitter() Ws2SD6!4`  
{ ti6\~SY  
return nSplitter; sDNV_} h  
} @ n<y[WA  
)c~1s  
TTB1}j+V6  
public void setNSplitter(int nCount) %@JNX}Y'  
{ zzmZ`Ya  
nSplitter = nCount; 5cLq6[uO  
} 2p'ujAK  
} ACQbw)tiv}  
' *hy!f]  
Mle@.IIT  
/* qbu>YTj  
**Utility.java %tx~CD  
*/ $@]tTz;b  
package NetFox; N$u;Q(^  
d:KUJ Y.  
2BTFK"=U  
public class Utility { F<SCW+>z2a  
g-B~" tp  
+%yVW f  
public Utility() m|mY_t  
{ cH$zDm1  
HzADz%~  
)C>4? )  
} 'EF\=o)^Y  
l+# l\q%l  
//线程睡眠 rKZ1 c,y  
public static void sleep(int nSecond) |a!AgvNF  
{ FFE IsB"9  
try{ +<cvyg5U  
Thread.sleep(nSecond); h4@v. GI  
} N^,@s"g  
catch(Exception e) 9Z! j  
{ jpND"`Q  
e.printStackTrace (); <PBrW#:'  
} bcgh}D  
} HK~uu5j  
?$ rSbw  
//日志 >:5^4/fo*  
public static void log(String sMsg) I'"b3]DXG  
{ +(>!nsf  
System.err.println(sMsg); f-at@C1L%L  
} *e E&ptx1  
S;0,UgB1  
*Q= 3v  
public static void log(int sMsg) !'-K>.B  
{ UzLe#3MU  
System.err.println(sMsg); 8;'fWV? U  
} Y yI4T/0s_  
} -b1VY4m-  
}%j@%Ep[  
u_0&`zq  
/* %lL^[`AR  
**TestMethod.java 7|~j=,HU+Z  
*/ FcR(uv<  
package NetFox; >s\j/yM  
FScE3~R  
l=jfgsjc  
public class TestMethod { d,"?tip/SX  
_)4YxmK%  
etY/K0  
public TestMethod() /.leY$  
{ ///xx/weblogic60b2_win.exe 4AI\'M"d  
try{ C^uH]WO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7C7eX J9q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z,'#=K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ],rtSUO  
fileFetch.start(); W/dl`UDY  
} *G{%]\s?  
catch(Exception e){e.printStackTrace ();} e}qG_*  
5w:   
@=KuoIV  
} !P*1^8b`f  
8= jl]q$<  
+J`EBoIo  
public static void main(String[] args) uo`O$k<;  
{ @^Tof5?F?  
new TestMethod(); "tu BfA+f  
} w#v8a$tT  
} hr%O4&sa  
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