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http断点续传简单实现(java)

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/* 4{U T!WIi  
**SiteFileFetch.java 9@(PWz=`?  
*/ E)5\i-n  
package NetFox; *20jz<  
import java.io.*;  EoR}Af  
import java.net.*; IqaT?+O\?r  
3 *"WG O5  
{0wIR_dGX  
public class SiteFileFetch extends Thread { t;}|tgC  
e "4 ''/  
\5:i;AE  
SiteInfoBean siteInfoBean = null; //文件信息Bean 5h=}j  
long[] nStartPos; //开始位置 %~H-)_d20  
long[] nEndPos; //结束位置 DFB@O|JL  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a`E#F] Z  
long nFileLength; //文件长度 qs6]-  
boolean bFirst = true; //是否第一次取文件 p Z|V 3  
boolean bStop = false; //停止标志 x_N'TjS^{  
File tmpFile; //文件下载的临时信息 x;P_1J%Q  
DataOutputStream output; //输出到文件的输出流 .\ULbN3Z  
2ozax)GY  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) XFHYQ2ME2  
public SiteFileFetch(SiteInfoBean bean) throws IOException yiXSYD  
{ S]e|"n~@  
siteInfoBean = bean; mP~QWx![N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WdH$JTk1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;>EM[u  
if(tmpFile.exists ()) >=I|xY,  
{ #4Rx]zW^%  
bFirst = false; TCwFPlF|  
read_nPos(); o4F2%0gJ  
} +s,=lL  
else !&y8@MD15  
{ ~*&H$6NJS  
nStartPos = new long[bean.getNSplitter()]; NqazpB*  
nEndPos = new long[bean.getNSplitter()]; w7.V6S$Ga  
} #Yj1w  
bQg:zww  
Ha0M)0Anv  
#C74z$  
} /!yU !`bY  
OhQgF  
%op**@4/t\  
public void run() Q^9_' t}X  
{ )Pa'UGY  
//获得文件长度 ah4N|zJ>v  
//分割文件 {Qf=G|Ah  
//实例FileSplitterFetch H7&8\ FNa  
//启动FileSplitterFetch线程 FF`T\&u  
//等待子线程返回  9X+V4xux  
try{ m{Wu" ;e  
if(bFirst) Y1W1=Uc uk  
{ urs,34h  
nFileLength = getFileSize(); ~tS Z%q  
if(nFileLength == -1) J9--tJ?[>o  
{ G#q@v(_b  
System.err.println("File Length is not known!"); TTX5EDCrC  
} ok"k*?Ov  
else if(nFileLength == -2) Y|F9}hj(  
{ I#Y22&G1  
System.err.println("File is not access!"); E1aHKjLQ  
} O_ muD\  
else njB;&N)I  
{ W dK #ZOR  
for(int i=0;i<nStartPos.length;i++) ?DS@e@lx  
{  c(f  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (?1y4M  
} ouvA~/5  
for(int i=0;i<nEndPos.length-1;i++) %ufN8w!p  
{ Af~$TyX  
nEndPos = nStartPos[i+1]; -e"H ^:  
} 6xx<Y2@  
nEndPos[nEndPos.length-1] = nFileLength; ~~/|dh5  
} 9IdA%RM~mH  
} \$~|ZwV{  
\g&,@'uh  
[B*x-R[FI  
//启动子线程 HTv2#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vFzRg5lH  
for(int i=0;i<nStartPos.length;i++) PfAgM1   
{ 7FP*oN?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $D~0~gn~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6m/r+?'  
nStartPos,nEndPos,i); U/66L+1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [x=s(:qy  
fileSplitterFetch.start(); :(U ,x<>  
} I;,77PxD  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eH'av}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3)t.p>VgO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Fj8z  
nEndPos = " + nFileLength); v|_K/|  
// fileSplitterFetch[nPos.length-1].start(); q"CVcLi9  
\"w"$9o6  
T$)^gHS  
//等待子线程结束 r..iko]T  
//int count = 0; *2>&"B09`  
//是否结束while循环 ;>U2|>5V  
boolean breakWhile = false; '2A)}uR  
3V+] 9;  
L~(j3D* 3  
while(!bStop) !]A  
{ 0I-9nuw,^;  
write_nPos(); ^&9zw\x;z  
Utility.sleep(500); Hs;4lSyUO  
breakWhile = true; ^  glri$m  
%vn"{3y>rF  
T#T*Zw"+  
for(int i=0;i<nStartPos.length;i++) j1Y~_  
{ L Tm2G4+]  
if(!fileSplitterFetch.bDownOver) R"/GQ`^AqA  
{ 59 T 8r  
breakWhile = false; {Y(zd[  
break; yM6pd U]i  
} nK1Slg#U  
} >mbHy<<  
if(breakWhile) a Yg6H2Un  
break; 1sy[ @Q2b  
G{As,`{  
ih-#5M@  
//count++; gMi0FO'  
//if(count>4) ]\-A;}\e  
// siteStop(); ch*8B(:  
} &@X<zWg  
p%up)]?0  
Pa>AWOG'  
System.err.println("文件下载结束!"); h"B+hu  
} \Gef \   
catch(Exception e){e.printStackTrace ();} hk;5w{t}}  
} f=+mIZ  
; }I:\P  
WMDl=6  
//获得文件长度 c8 )DuJ#U  
public long getFileSize() @W.S6;GA\  
{ F>Ah0U0  
int nFileLength = -1; z#9aP&8Q  
try{  h},IF  
URL url = new URL(siteInfoBean.getSSiteURL());  Po+.&7F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X;+sUj8  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~Py`P'+  
;DQ ZT  
A7 {\</Z  
int responseCode=httpConnection.getResponseCode(); P_^ +A  
if(responseCode>=400) L?b~k=  
{ w?PkO p  
processErrorCode(responseCode); Qab>|eSm  
return -2; //-2 represent access is error Ve$o}h-  
} J'6PmPzY|  
Xz 6<lLb  
df8k7D;~e  
String sHeader; l ~"^7H?4e  
3GYw+%Z]  
nAAs{  
for(int i=1;;i++) ;$,U~0  
{ 7DogM".}~Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5+4IN5o]=  
//Utility.log(in.readLine()); >a<.mU|#  
sHeader=httpConnection.getHeaderFieldKey(i); Pjf"CW+A  
if(sHeader!=null) wq`s-qZu  
{ }^WdJd]P  
if(sHeader.equals("Content-Length")) RF$eQzW  
{ d UE,U=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .<0ye_S'y  
break; 98c(<  
} =`oCLsz=  
} )b L'[h  
else l+K'beP  
break; wQl ,  
} tPWLg),  
} & GO}|W  
catch(IOException e){e.printStackTrace ();} /|m2WxK)  
catch(Exception e){e.printStackTrace ();} <Xhm`rH  
];$L &5^  
s*KhF'fN  
Utility.log(nFileLength); XAKs0*J>  
h]&GLb&<?  
wD}l$ & +  
return nFileLength; .&iawz  
} a#(?P.6  
#<"~~2?  
m#Jmdb_  
//保存下载信息(文件指针位置) |)DGkOtd  
private void write_nPos() HXC ;Np  
{ ITXa&5D  
try{ fSj5ZsO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 7vKK%H_P  
output.writeInt(nStartPos.length); F@jZ ho  
for(int i=0;i<nStartPos.length;i++) VR8-&N  
{ V*;(kEqj  
// output.writeLong(nPos); GT.,  
output.writeLong(fileSplitterFetch.nStartPos); np^N8$i:n  
output.writeLong(fileSplitterFetch.nEndPos); dm0R[[7  
} yx8z4*]kH  
output.close(); wo{gG?B  
} `:fZ)$sY  
catch(IOException e){e.printStackTrace ();}  :A_@,Q  
catch(Exception e){e.printStackTrace ();} ,Ks8*;#r  
} WM$ MPs  
LKB$,pR~1l  
Y=?3 js?O  
//读取保存的下载信息(文件指针位置) ;u ({\K  
private void read_nPos() Zd%k*BC  
{ =%K;X\NB  
try{ zV37$Hb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :gibfk]C  
int nCount = input.readInt(); /)>3Nq4Zx  
nStartPos = new long[nCount]; Y;M|D'y+  
nEndPos = new long[nCount]; 1z4OI6$Af  
for(int i=0;i<nStartPos.length;i++) BsDn5\ q  
{ [ -K&R  
nStartPos = input.readLong(); ^ig' bw+WS  
nEndPos = input.readLong(); h 0Q5-EA  
} 9d659i C  
input.close(); e\l7Iu  
} UYJZYP%r  
catch(IOException e){e.printStackTrace ();} 13=AW  
catch(Exception e){e.printStackTrace ();} kd(8I_i@  
} `wEb<H  
20h, ^  
.f2bNnB~pP  
private void processErrorCode(int nErrorCode) g}{aZ$sta  
{ RWZSQ~  
System.err.println("Error Code : " + nErrorCode); ;7V%#-  
} L|7R9+ZG  
]y '>=a|T  
^A/k)x6  
//停止文件下载 g3/W=~r  
public void siteStop() 83\pZ1>)_  
{ } 9Eg=%0v  
bStop = true; B%b4v  
for(int i=0;i<nStartPos.length;i++) u'DRN,h+  
fileSplitterFetch.splitterStop(); xGg )Y#  
F^BS/Yag  
Qbn"=n2  
} J/aC}}5D  
} CYP q#rd  
//负责部分文件的抓取 .@U@xRu7|  
**FileSplitterFetch.java _7 L-<  
*/ ?Ep [M:,q  
package NetFox; K=k"a  
"?xHlYj@+  
}2.`N%[  
import java.io.*; /nNN,hz  
import java.net.*; J=I:CD%  
Y"aJur=`  
nRS}}6Q  
public class FileSplitterFetch extends Thread { ?P`K7  
a~}OZ&PG  
1};Stai'  
String sURL; //File URL \&3+D8H>n  
long nStartPos; //File Snippet Start Position zP8lN(LA  
long nEndPos; //File Snippet End Position 5x4yyb'  
int nThreadID; //Thread's ID Id .nu/  
boolean bDownOver = false; //Downing is over pJ"qu,w  
boolean bStop = false; //Stop identical IueFx u  
FileAccessI fileAccessI = null; //File Access interface )23H1  
Ckuh:bs  
cf20.F{<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7' V@+5  
{ />pI8 g<  
this.sURL = sURL; _op}1   
this.nStartPos = nStart; 6iE<T&$3P  
this.nEndPos = nEnd; 9IfmW^0  
nThreadID = id; ~KX/ Ai  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 q ^N7 I@Y  
} l4YJ c  
{@{']Y  
Vaw+.sG`AP  
public void run() m nX2a  
{ :KP @RZm  
while(nStartPos < nEndPos && !bStop) giw &&l=_  
{ hRCJv#]HC  
k(G^z   
"_NN3lD)X  
try{ _9Te!gJ4_#  
URL url = new URL(sURL); WO>nIo5Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D8?Vn"  
httpConnection.setRequestProperty("User-Agent","NetFox"); s$`0yGmQ  
String sProperty = "bytes="+nStartPos+"-"; D'PI1 0t  
httpConnection.setRequestProperty("RANGE",sProperty); c]o'xd,T8\  
Utility.log(sProperty); {]@= ijjf  
YZ8>OwQz2  
0-Ku7<a  
InputStream input = httpConnection.getInputStream(); V5>B])yQ  
//logResponseHead(httpConnection); )' cMYC  
yjJ5>cg  
@:vwb\azVD  
byte[] b = new byte[1024]; `kXs;T6&  
int nRead; y/7\?qfTk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xdt- ;w|  
{ Q\7h`d%)  
nStartPos += fileAccessI.write(b,0,nRead); Ie#Bkw'*  
//if(nThreadID == 1) vr6w^&[c^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A]oV"`f  
} p]+Pkxz]'  
>@_^fw)  
uZKr  
Utility.log("Thread " + nThreadID + " is over!"); 6 V=9M:  
bDownOver = true; I-(zaqp@  
//nPos = fileAccessI.write (b,0,nRead); SZ'R59Ee<  
} flbd0NB  
catch(Exception e){e.printStackTrace ();} ;$wVu|&  
} !?h;wR  
} ^k">A:E2  
:OT0yA=U  
d^ 8ZeC#  
//打印回应的头信息 u `6:5k  
public void logResponseHead(HttpURLConnection con) !z3jTv  
{ })Vi  
for(int i=1;;i++) %l[( Iw  
{ >} i  E(  
String header=con.getHeaderFieldKey(i); :':s@gqr  
if(header!=null) n;Vs_u/Nx  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p}~JgEE  
Utility.log(header+" : "+con.getHeaderField(header)); SoK iE  
else VjZ|$k  
break; "@0]G<H  
} 7;wd(8  
} yN(%-u"  
-x`@6  
o]oum,Q  
public void splitterStop() &d^m 1  
{ S;#'M![8  
bStop = true; /@TF5]Ri  
} je=a/Y=%U{  
yYA$I'Bm\  
z<XtS[ki  
} ,w4V?>l  
aj{Y\ 3L  
m~0/&RA  
/* $B5aje}i  
**FileAccess.java r52gn(,  
*//文件访问(定位,写) 6mxfLlZ  
package NetFox; 00~mOK;1  
import java.io.*; ~V1E0qdAE  
}N6.Uu 5zI  
VTY 5]|;  
public class FileAccessI implements Serializable{ e=m42vIB-  
RQ" ,3.R==  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?J~_R1Z  
RandomAccessFile oSavedFile; ^o&. fQ*  
long nPos; Z o(rTCZX  
z5*'{t)  
u <v7;dF|s  
public FileAccessI() throws IOException ?J >  
{ 7?w*]  
this("",0); 6q.Uhe_B  
} d S V8q ,D  
E""bTz@  
F0Yd@Lk$_  
public FileAccessI(String sName,long nPos) throws IOException *#+An<iT ;  
{ z[qDkL  
oSavedFile = new RandomAccessFile(sName,"rw"); 3 {sVVq5Y  
this.nPos = nPos; T'Dv.h  
oSavedFile.seek(nPos); [2 M'PT3  
} T%*D~=fQ'  
]2qo+yB  
ee76L&:  
public synchronized int write(byte[] b,int nStart,int nLen) \d`h/tHk  
{ |[b{)s?x  
int n = -1; t!7-DF|N  
try{ ZyFjFHe+  
oSavedFile.write(b,nStart,nLen); z1X`o  
n = nLen; <*cikXS  
} LG#t<5y~  
catch(IOException e) {9.|2%a  
{ A#YrWW  
e.printStackTrace (); (V2fRv  
} 8XE7]&)];  
iSs:oH3l  
[FR`Z=%  
return n; oE]QF.n#  
} -]M5wb2,  
G2: agqL/  
hv>\gBe i  
} NU2;X (z[  
tf`^v6m%]  
sdw(R#GE  
/* IyG}H}  
**SiteInfoBean.java c(s.5p ^  
*/ /aZ`[m2  
package NetFox; M[,@{u/  
s|r3Gv|G  
h>m"GpF x  
public class SiteInfoBean { k~1?VQ+?M  
>}6%#CAf  
draN0v f  
private String sSiteURL; //Site's URL &6nWzF  
private String sFilePath; //Saved File's Path ~oY^;/ j  
private String sFileName; //Saved File's Name \z(gqkc 6  
private int nSplitter; //Count of Splited Downloading File q^<?]8  
II{&{S'HU  
Qd3 j%(  
public SiteInfoBean() Wg]Qlw`\|  
{//nSplitter的缺省值为5 5VU2[ \  
//default value of nSplitter is 5 Y`a3tO=Pd  
this("","","",5); {F.[&/A  
} nZYBE030  
/f;~X"!  
t;\Y{`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XU(eEnmo m  
{ 4@ai6,<  
sSiteURL= sURL; o0KL5].  
sFilePath = sPath; ##"HF  
sFileName = sName; Oxd]y1  
this.nSplitter = nSpiltter; ]~3V}z,T*  
-6B4sZpzD  
r mg}N  
} +TDw+  
QhJiB%M  
8 v%o,"  
public String getSSiteURL() &^Q/,H~S  
{ c\AfaK^KF  
return sSiteURL; ;u)I\3`*!  
} $*fMR,~t&  
|@4' <4t  
g]0_5?i  
public void setSSiteURL(String value) P-"y3 ZE=  
{ 7zG_(83)K  
sSiteURL = value; [.wYdv35  
} xU`p|(SS-  
vy I!]p  
T9   
public String getSFilePath() B tcy)LRk  
{ /IMFO:c  
return sFilePath; 0n{=%Q  
} h~zT ydnH  
Ig>(m49d  
E r?&Y,o  
public void setSFilePath(String value) %1+4_g9  
{ (SAs-  
sFilePath = value; Rnq7LGy  
} )+9Uoe~6  
$~T4hv :  
9XB8VKu8  
public String getSFileName() {I't]Qj_e  
{ nAdf=D'P  
return sFileName; |&i<bqLw:  
} {"KMs[M  
`<d }V2rdz  
}@d@3  
public void setSFileName(String value) \,0oX!<YY  
{ 2<}%kQ`  
sFileName = value; L ~N460  
} h <<v^+m  
?4T-@~~*`=  
ysY*k`5  
public int getNSplitter() /N.U/MPL_  
{ 5`p.#  
return nSplitter; ;;/{xvQ.1  
} ;9QEK]@  
p9-K_dw3X@  
AFwdJte9e  
public void setNSplitter(int nCount) uQKT  
{ 63IM]J  
nSplitter = nCount; a9Zq{Ysj  
} [(7S.5I  
} ] Zh%DQ  
SOA,kwHRe  
5\VWCI  
/* c@L< Z`u  
**Utility.java U|R_OLWAg  
*/ S{T >}'y  
package NetFox; ]3Sp W{=^(  
q'Pf]  
7;@]t^d=$  
public class Utility { /Lr.e%  
 o-B$J?  
X|]A T9W  
public Utility() >Cq<@$I2EB  
{ mj7#&r,1l  
5*u+q2\F  
=>~:<X.,  
} E|shs=I  
8P\Zo8}v  
//线程睡眠 ) ;Y;Q  
public static void sleep(int nSecond) iuul7VR-%  
{ Dk51z@  
try{ 'i|YlMFIg  
Thread.sleep(nSecond); >Y@H4LF;1x  
} M x" \5i  
catch(Exception e) z},# ~L6$q  
{ jq0O22 -R  
e.printStackTrace (); W: z;|FF  
} Q\sK"~@3  
} ]JQULE)  
m+z& Q  
//日志 =~LJ3sIX  
public static void log(String sMsg) Z*6IW7#  
{ ":N9(}9  
System.err.println(sMsg); 9 QJyZ  
} 4Ftu  
l,aay-E  
V0a3<6@4  
public static void log(int sMsg) w7&A0M  
{ k$:|-_(w  
System.err.println(sMsg); t4-[Z$ n5  
} TIg3` Fon  
} B^ }yo65I  
{R{=+2K!|k  
[0("Q;Ec[j  
/* XW92gI<O  
**TestMethod.java 9H1rO8k  
*/ +:/%3}`  
package NetFox; < I``&>  
as =fCuJ  
%^6F_F_jS  
public class TestMethod { {?7Uj  
w_VP J  
0JujesUw(  
public TestMethod() Zx>=tx}  
{ ///xx/weblogic60b2_win.exe Q22 GIr  
try{ +&H4m=D-#a  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); E' uZA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;}p  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ab;.5O$y  
fileFetch.start(); t sRdvFFq  
} A^SgI-y|  
catch(Exception e){e.printStackTrace ();} E92-^YY  
|u p  
?+8\.a!  
} uCB=u[]y4  
;722\y(Y  
z\4.Gm-  
public static void main(String[] args) `uTmw^pZX  
{ 1G`Pmh@  
new TestMethod(); X2"/%!65{  
} >/6 _ ^  
} {id4:^u&;  
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