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http断点续传简单实现(java)

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/* )oU)}asY  
**SiteFileFetch.java (\,BxvhG=  
*/ 3[IJhR[  
package NetFox; 9}P"^N  
import java.io.*; Gy"%R-j7  
import java.net.*; U BZ9A  
>#(n"RCHf  
bw4oLu?  
public class SiteFileFetch extends Thread { 7J*N_8?2  
6bO~/mpWT~  
a~ ]bD  
SiteInfoBean siteInfoBean = null; //文件信息Bean 'g)n1 {  
long[] nStartPos; //开始位置 U|@V 74  
long[] nEndPos; //结束位置 d=3'?l`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _yH`t[  
long nFileLength; //文件长度 }-DE`c  
boolean bFirst = true; //是否第一次取文件 jqnCA<G~B-  
boolean bStop = false; //停止标志 D'_Bz8H!p  
File tmpFile; //文件下载的临时信息 h|;qG)f^  
DataOutputStream output; //输出到文件的输出流 C~4PE>YtTv  
%.HJK  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) zsXpA0~3s  
public SiteFileFetch(SiteInfoBean bean) throws IOException E JK0  
{ #8h ;Bj  
siteInfoBean = bean; p(JlvJjo  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); c EnkU]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FjFMR 63  
if(tmpFile.exists ()) Di5(9]o2  
{ LT@OWH  
bFirst = false; 1X1 N tS @  
read_nPos(); ;_?MX/w|&  
} !>$4]FkV  
else {+.r5py  
{ |L6&Gf]#5  
nStartPos = new long[bean.getNSplitter()]; DcD{*t?x  
nEndPos = new long[bean.getNSplitter()]; 1Sz A3c  
} JXqr3 Np1  
l$xxrb9P!  
GqKsK r2%  
zaimGMJ ,  
} B 0ee?VC  
Wp0 Dq(  
]wVk+%e  
public void run() YT#3n  
{ aA'TD:&p1  
//获得文件长度 s5&@Cxzl  
//分割文件 #*%q'gyHT  
//实例FileSplitterFetch tY|8s]{2  
//启动FileSplitterFetch线程 Nw_@A8-r  
//等待子线程返回 G}d-(X  
try{ nY%5cJ`"  
if(bFirst) p#P~Q/;  
{ /=?x{(B>  
nFileLength = getFileSize(); q2aYEuu,  
if(nFileLength == -1) N)2f7j4C &  
{ nIk$7rGLB  
System.err.println("File Length is not known!"); V$`Gwr]|n  
} U(>4s]O6  
else if(nFileLength == -2) 6IcNZ!j98  
{ H}}$V7]^),  
System.err.println("File is not access!"); *e>]~Z,  
} 7[#yu2  
else _qwQ;!9  
{ ;,h/   
for(int i=0;i<nStartPos.length;i++) %ysZ5:X  
{ CY:d`4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~uWOdm-"[  
} &[vw 0N-  
for(int i=0;i<nEndPos.length-1;i++) (2ot5x}`j  
{ Sjj>#}U  
nEndPos = nStartPos[i+1]; =8Jfgq9E  
} M~e0lg8  
nEndPos[nEndPos.length-1] = nFileLength; :M3oUE{  
} thlY0XCq,%  
} ;|T!#@j  
N "tFP9;K  
BR`ygrfe  
//启动子线程 OR1DYHHT/1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y&~w2{a  
for(int i=0;i<nStartPos.length;i++) Vv.r8IGYm  
{ :ue:QSt(u  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *|.0Myjo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gmKGy@]  
nStartPos,nEndPos,i); =W bOwI)u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Bq\F?zk<  
fileSplitterFetch.start(); p9!"O  
} /1=4"|q>h'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Rd \.:u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); c,MOv7{x_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s9;#!7ms  
nEndPos = " + nFileLength); 'NjzgZ~]P  
// fileSplitterFetch[nPos.length-1].start(); 7,qYV}  
E51dV:l  
}_/Hdmmx  
//等待子线程结束 O|IG_RL]  
//int count = 0; BF*kb2"GZ6  
//是否结束while循环 $ i)bq6  
boolean breakWhile = false; @}p2aV59  
H(c72]@Vg  
lf{e[!ML'  
while(!bStop) ~)LH='|h\}  
{ E907fX[R~  
write_nPos(); Ix@&$!'k  
Utility.sleep(500); e1(Q(3  
breakWhile = true; /-_=nf}w  
x5`br.b  
|:[tNs*,O  
for(int i=0;i<nStartPos.length;i++) +CH},@j  
{ K;?,FlH  
if(!fileSplitterFetch.bDownOver) <~ad:[  
{ 6fH@wQ"wN  
breakWhile = false; q\Q{sv_  
break; (/!r(#K0,'  
} #4MBoN(3  
} <9E0iz+j  
if(breakWhile) ptatzp]c#  
break; 5Wyz=+?m|  
qf@q]wtar  
LZJA4?C  
//count++; Ee)[\Qjn  
//if(count>4) Ds #/  
// siteStop(); k Iw`P[  
} E#J';tUQ  
Wt)Drv{@ {  
'w>_+jLT  
System.err.println("文件下载结束!"); #/"8F O%~p  
} mpAR7AG6  
catch(Exception e){e.printStackTrace ();} W>r#RXmh  
} >EL)X #e  
hT$~ygQ  
qPB8O1fyU  
//获得文件长度 H9h@sSg  
public long getFileSize() IEKU-k7}Z  
{ #_lt~^ 6  
int nFileLength = -1; C{sLz9  
try{ U~h'*nV&  
URL url = new URL(siteInfoBean.getSSiteURL()); xq-17HKs  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7^wc)E^H  
httpConnection.setRequestProperty("User-Agent","NetFox"); :tIC~GG]_)  
IDkWGh  
*n]7  
int responseCode=httpConnection.getResponseCode(); 2LrJ>Mi  
if(responseCode>=400) ~$' \L  
{ \!(  
processErrorCode(responseCode); 'O5'i\uz  
return -2; //-2 represent access is error RZM"~ 0  
} D3|oOOoG  
QM3,'?ekRH  
0TfS=scT  
String sHeader;  tz#gClo  
4h@Z/G!T3  
/9o!*K  
for(int i=1;;i++) JnHo9K2.  
{ !d<"nx[2`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k(zsm"<q  
//Utility.log(in.readLine()); V .os  
sHeader=httpConnection.getHeaderFieldKey(i); O: @}lK+H  
if(sHeader!=null) NCxqh<  
{ RoCfJ65  
if(sHeader.equals("Content-Length")) hN['7:bQ  
{ V"p!B f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M?=;JJ:  
break; da1]mb=4 5  
} GN KF&M  
} OB[o2G<0  
else 'n<iU st  
break; SyAvKd`g  
} /C/id)h>  
} )p!7 #v/@f  
catch(IOException e){e.printStackTrace ();} jiF?fX@  
catch(Exception e){e.printStackTrace ();} U4 13?Pe  
D:Q 21Ch  
IbcZ@'RSw  
Utility.log(nFileLength); >^Se'SE]  
-n'F v@U  
)c l5B{1P  
return nFileLength; aM7uBx\8 5  
} >A0k 8T  
RI68%ZoL  
sXd8rj:o  
//保存下载信息(文件指针位置) rr#K"SP  
private void write_nPos()  ;raN  
{ B||;'  
try{ -P&6L\V  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9f\/\L  
output.writeInt(nStartPos.length); W8lx~:v  
for(int i=0;i<nStartPos.length;i++) 5,)Q w  
{ p7:{^  
// output.writeLong(nPos); AfG/JWSo}  
output.writeLong(fileSplitterFetch.nStartPos); WK="J6K5  
output.writeLong(fileSplitterFetch.nEndPos); w.& 1%X(k  
} '#(v=|J  
output.close(); )K'N(w  
} aZEn6*0B  
catch(IOException e){e.printStackTrace ();} <C9 XX~  
catch(Exception e){e.printStackTrace ();} [F5h   
} ""s]zNF}  
0rGSH*(  
' B  
//读取保存的下载信息(文件指针位置) ICAH G7,  
private void read_nPos() Me6+~"am/  
{ .S(,o.  
try{ ~+Z{Q25R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :VF<9@t  
int nCount = input.readInt(); lg047K   
nStartPos = new long[nCount]; OgF+O S  
nEndPos = new long[nCount]; jE#O>3+.  
for(int i=0;i<nStartPos.length;i++) gKOOHUCb  
{ ,;M4jc {  
nStartPos = input.readLong(); !"+'A)Nve  
nEndPos = input.readLong(); iS5W>1]  
} O5H9Y}i]  
input.close(); hDV20&hq  
} F@R1:M9*  
catch(IOException e){e.printStackTrace ();} 3s"0SLS4  
catch(Exception e){e.printStackTrace ();} PvGDTYcKp  
} 31EyDU,W  
RZ1 /#;  
Fu^ ^i&  
private void processErrorCode(int nErrorCode) &K/FyY5  
{ \^#~@9  
System.err.println("Error Code : " + nErrorCode); W+*5"h  
} *m2=/Sh  
gIA@l `"  
sBV 4)xM  
//停止文件下载 1Z{ZV.!  
public void siteStop() O$IjN x  
{ m^x6>9,  
bStop = true; D~o$GW%  
for(int i=0;i<nStartPos.length;i++) N41R  
fileSplitterFetch.splitterStop(); /O ]t R  
D5~n/.B"  
pH`44KAuM  
} p _d:eZ  
} KRjV}\}  
//负责部分文件的抓取 4e;QiTj  
**FileSplitterFetch.java =}PdH`S  
*/ BcD&sQ2F  
package NetFox; )]#aauC+  
]0L&v7[  
xV%6k{_:G  
import java.io.*; * !^<m0  
import java.net.*; 8BvonY t=8  
jNeI2-9c}  
h5yzwj:C?  
public class FileSplitterFetch extends Thread { :UJa&$)  
m~uOXb  
y*MF&mQ[  
String sURL; //File URL ':R,53tjl  
long nStartPos; //File Snippet Start Position 7mm1P9Z  
long nEndPos; //File Snippet End Position `gKf#f  
int nThreadID; //Thread's ID .k[o$z\EkF  
boolean bDownOver = false; //Downing is over x1 1U@jd+1  
boolean bStop = false; //Stop identical  ["}rk  
FileAccessI fileAccessI = null; //File Access interface T)\"Xj  
k? Xc  
![f ![l  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /t-fjB{=G  
{ vd6l7"0/  
this.sURL = sURL; H~ u[3LQz  
this.nStartPos = nStart; 6=N`wi  
this.nEndPos = nEnd; :rP#I#,7w  
nThreadID = id; >[6{LAe~hp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?bw4~  
} <'G~8tA%v  
`-3o+ID\  
-X+H2G  
public void run() wb Iq&>p  
{ c)0amM  
while(nStartPos < nEndPos && !bStop) \ u_ui  
{ z#F.xVg'  
DS|KkTy3  
sKyPosnP  
try{ fg#x7v4O  
URL url = new URL(sURL); ](F#`zUQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -+t]15  
httpConnection.setRequestProperty("User-Agent","NetFox"); *%vwM7  
String sProperty = "bytes="+nStartPos+"-"; `>o?CIdp  
httpConnection.setRequestProperty("RANGE",sProperty); {,OS-g  
Utility.log(sProperty); TE )gVE]  
`mT$s,:h  
9C t`  
InputStream input = httpConnection.getInputStream(); ud fe  
//logResponseHead(httpConnection); ddVa.0Z!<  
G^"Vo x4  
KN"S?i]X  
byte[] b = new byte[1024]; T;L>P[hNn  
int nRead; hm<}p&!J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) N8`?t5  
{ Z0De!?ALV\  
nStartPos += fileAccessI.write(b,0,nRead); XlI!{qj|  
//if(nThreadID == 1) R}mn*h6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z/rTVAs@r  
} #yI.nzA*  
PR|R`.QSs  
,#W  
Utility.log("Thread " + nThreadID + " is over!"); 5<L_|d)0"  
bDownOver = true; |y20Hi':  
//nPos = fileAccessI.write (b,0,nRead); tRpEF2  
} %zU`XVNN+  
catch(Exception e){e.printStackTrace ();} =uDgzdDyE  
} <}6{{&mT4  
} Jgu94.;5  
-CH`>  
n41@iK2l  
//打印回应的头信息 wW?,;B'74  
public void logResponseHead(HttpURLConnection con) L !4t[hhe=  
{ Q!,<@b)  
for(int i=1;;i++) $;G{Pyp  
{ /=uMk]h  
String header=con.getHeaderFieldKey(i); Vx_rc%'  
if(header!=null) f.GETw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a{Esw`  
Utility.log(header+" : "+con.getHeaderField(header)); ;IK[Y{W/  
else Jx#k,Z4  
break; v+"rZ  
} '&;yT[  
} aQ j*KMc  
)EyI0R]5  
+jC*'7p@  
public void splitterStop() OdI\B   
{ ^w~23g.  
bStop = true; 9;%CHb&  
} *c[2C  
t?nX=i*~]  
|lH;Fq{\  
} j'i0*"x  
ZtVAEIZ)  
y$hp@m'@C  
/* midsnG+jnf  
**FileAccess.java TO,rxf  
*//文件访问(定位,写) `IINq{Zk  
package NetFox; FI8Oz,  
import java.io.*; A$g+K,.l  
G1 o70  
~8|t*@D  
public class FileAccessI implements Serializable{ gqib:q ;r  
W\f9jfD  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 avp; *G }  
RandomAccessFile oSavedFile; <ktzT&A  
long nPos; )x#5Il H  
]<DNo&fw  
9]$8MY   
public FileAccessI() throws IOException ,D6v4<jh  
{ m\ /(w_/?  
this("",0); \bCX=E-  
} 8 6QE /M  
@+U,Nzd  
H(0q6~|  
public FileAccessI(String sName,long nPos) throws IOException UkCnqNvx  
{ /\mKY%kyh  
oSavedFile = new RandomAccessFile(sName,"rw"); zT~B 6  
this.nPos = nPos; (wRBd  
oSavedFile.seek(nPos); =\)IaZ  
} /W#O +  
3>z[PPw  
;evCW$G=  
public synchronized int write(byte[] b,int nStart,int nLen) 0e["]Tlnm  
{ l6[lJ0Y  
int n = -1; \F,DA"K_  
try{ }W)=@t  
oSavedFile.write(b,nStart,nLen); iNCX:Y  
n = nLen; v}J;ZIb  
} )_zlrX  
catch(IOException e) RANPi\]  
{ #y]3LC#)^G  
e.printStackTrace (); yj@tV2  
} [-*F"}D,  
~#:e*:ro  
k6IG+:s  
return n;  V[pvJ(  
} C-P06Q]  
c.H?4j7ga  
PBks` |+  
} RK9>dkW  
O}Ui`eWU  
VS?@y/\In  
/* `29TY&p+"  
**SiteInfoBean.java '!v c/Hw  
*/ LU!1s@  
package NetFox; -'rj&x{Q)U  
")s!L"x  
d_}a`H  
public class SiteInfoBean { HW=xvA+  
"C%!8`K{a*  
;Hm'6TR!  
private String sSiteURL; //Site's URL rqCa 2  
private String sFilePath; //Saved File's Path wCZO9sU:6=  
private String sFileName; //Saved File's Name QL"gWr`R  
private int nSplitter; //Count of Splited Downloading File D_|B2gdZY  
hQJWKAf,/  
a! Yb1[  
public SiteInfoBean() nN`"z3o  
{//nSplitter的缺省值为5 w#PZu+  
//default value of nSplitter is 5 ZofHi c  
this("","","",5); U2*6}c<  
} `0BdMKjA  
a ib}`l  
^[h2%c$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2xmk,&s  
{ HOYq?40.R  
sSiteURL= sURL; 5!fSW2N  
sFilePath = sPath; #G _/.h@  
sFileName = sName; x;$|#]+  
this.nSplitter = nSpiltter; D#sf i,O  
].DY"  
'\p;y7N  
} SqB/4P   
m>Ux`Gp+  
UFZ"C,  
public String getSSiteURL() 24@^{ }  
{ 1czG55 |  
return sSiteURL; d5xxb _oE  
} y[HQBv  
*)VAaGUX>  
7{BnXN[  
public void setSSiteURL(String value) hd^x}iK"  
{ vrcE]5(:s  
sSiteURL = value; fDuwgY0  
} q G ;-o)h  
\v`#|lT$  
^/KfH &E  
public String getSFilePath()  ';lfS  
{ |n P_<9[  
return sFilePath; P!\hnm)%4  
} lC9S\s  
N2~$r pU3  
cIw eBDl  
public void setSFilePath(String value) ;bHfn-X  
{ oXc/#{NC  
sFilePath = value; j8 H Oc(  
} [%.18FWI  
G j6. Iv  
2:J,2=%  
public String getSFileName() KVijs1q  
{ hYvNcOSks  
return sFileName; BF|*"#s  
} 4: sl(r  
{ vfq  
(L#%!bd  
public void setSFileName(String value) 1k>naf~O  
{ gg8c7d:Q  
sFileName = value; GJak.,0t  
} AUAI3K?  
d7~j^v)=^  
9y+[o  
public int getNSplitter() NiTJ}1 l  
{ )1_(>|@oi  
return nSplitter; :GL7J6  
} UD*+"~  
]V<"(?,K  
:o\5K2]:  
public void setNSplitter(int nCount) B T7Id  
{ "|4jP za  
nSplitter = nCount; E/"SU*Co  
} `` -k{C#F  
} ^g]xU1] *  
=x4a~=HX  
9-- dRTG  
/* =h\E<dw  
**Utility.java } J;~P 9Y  
*/ iBHw[X,b  
package NetFox; t{ H 1u  
STlPT5e.}  
.YiaXP  
public class Utility { 5+FLSk  
oWD)+5. ]  
7)PJ:4IqS  
public Utility() DyX0 xx^  
{ @ KJV1t`  
?>)yKa#U  
/| f[us-w  
} uo 4xnzc  
"UpOY  
//线程睡眠 ,eK2I Ao  
public static void sleep(int nSecond) q2Rf@nt  
{ $`Rxn*}V4#  
try{ #7C6yXb%  
Thread.sleep(nSecond); V2QW\2@$  
} JX&~y.F  
catch(Exception e) ;Xh5oB\)W  
{ [0(mFMC`  
e.printStackTrace (); cyb(\ fsC  
} \>;%Ji  
} &E]"c]i+  
<{ # <5 8  
//日志 |` v^d|  
public static void log(String sMsg) ]Da4.s*mW  
{ @SQceQfB  
System.err.println(sMsg); R_9 o!s TZ  
} =SL^>HS.fo  
S| "TP\o  
PHl4 vh#E!  
public static void log(int sMsg) R25-/6_V>  
{ XC}1_VWs  
System.err.println(sMsg); :3gFHBFDj  
} (k#t }B[  
} * 2%oZX F  
[U']kt  
bQpoXs0w;  
/* #8&#E?^d  
**TestMethod.java Hi7G/2t@`  
*/ 8'% +G  
package NetFox; "Y(%oJS]D  
]]3Q*bq4  
q!@c_o  
public class TestMethod { D zE E:&*=  
U-ULQ|6U  
|QMT A5  
public TestMethod() Y}ky/?q  
{ ///xx/weblogic60b2_win.exe @QX4 \  
try{ 5 Af?Yxv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8ur_/h7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); r.Lx%LZ\^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sHF%=Vu  
fileFetch.start(); tB !|p6  
} gvK"*aIj  
catch(Exception e){e.printStackTrace ();} ^:U;rHY  
g.=!3e&z%  
s1v{~xP  
} %27G2^1  
H'']J9O  
Mi;Tn;3er  
public static void main(String[] args) o=@ UXi  
{ Hj1k-Bs&'w  
new TestMethod(); W >Kp\tD  
} s7AI:Zv  
} nT)~w s  
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