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http断点续传简单实现(java)

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/* ^1Zq0  
**SiteFileFetch.java 7@y!R   
*/ )|^<woli,  
package NetFox; d>"$^${  
import java.io.*; z.9FDQLp  
import java.net.*; \,bFm,kC?  
]Y: W[p  
eGypXf%  
public class SiteFileFetch extends Thread { :-W CW);N  
o` 1V  
NF\^'W@N  
SiteInfoBean siteInfoBean = null; //文件信息Bean w4MMo  
long[] nStartPos; //开始位置 @61N[  
long[] nEndPos; //结束位置 k -DB~-L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Pc; 14M  
long nFileLength; //文件长度 =jv$ 1  
boolean bFirst = true; //是否第一次取文件 K#C56k q&  
boolean bStop = false; //停止标志 TYS\:ZdXF  
File tmpFile; //文件下载的临时信息 RJs G]`  
DataOutputStream output; //输出到文件的输出流 GxBPEIim  
8qYGlew,  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) L\?g/l+k  
public SiteFileFetch(SiteInfoBean bean) throws IOException yY-t4WeXP  
{ M^Ay,jK!  
siteInfoBean = bean; jc~*#\N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2c`=S5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (Rg!km%2T  
if(tmpFile.exists ()) ,Yprk%JT  
{ Sq8Q *  
bFirst = false; k|c0tvp  
read_nPos(); {,C8}8 a W  
} /?-p^6U  
else `1}?{ud  
{ _3G)S+ 7#  
nStartPos = new long[bean.getNSplitter()]; [W;dguh  
nEndPos = new long[bean.getNSplitter()]; BRzWZq%r3  
} {s'_zS z  
Y^m=_*1g5  
'\E{qlI  
Vyq<T(5  
} |laKntv2  
YeVc,B'  
H^1 a3L]  
public void run() D!T4k]^  
{ JG4*B|3  
//获得文件长度 vA-p} ]%  
//分割文件 :#htOsP  
//实例FileSplitterFetch bYB}A :  
//启动FileSplitterFetch线程 TY[d%rMm  
//等待子线程返回 GaqG 8% .  
try{ [ .uaO  
if(bFirst) g E+OQWu  
{ =i>F^7)U1  
nFileLength = getFileSize(); &b")`p&K  
if(nFileLength == -1) C|@k+^S  
{ m`q> _*  
System.err.println("File Length is not known!"); \.|A,G=  
}  CF92AY  
else if(nFileLength == -2) ^&/&I9z  
{ .eXA.9 |jm  
System.err.println("File is not access!"); 'J0s%m|j  
} Ngc+<  
else 0F'UFn>{  
{ rAw1g,&  
for(int i=0;i<nStartPos.length;i++) NKhR%H  
{ #$B,8LFz,$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); z n8ig/C  
} U`_vF~el~  
for(int i=0;i<nEndPos.length-1;i++) )&!@O$RS8(  
{ E!l1a5qB  
nEndPos = nStartPos[i+1]; 5GL+j%7  
} G-?9;w'@  
nEndPos[nEndPos.length-1] = nFileLength; b<78K5'  
} gO!h<1!  
} je3n'^m  
<7] Y\{+  
ioCkPj  
//启动子线程 R+hS;F nh%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q$'&RG  
for(int i=0;i<nStartPos.length;i++) oxXW`C<  
{ 0BE^qe  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ByvqwJY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), { (,vm}iFL  
nStartPos,nEndPos,i); -"K:ve(K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -\C6j  
fileSplitterFetch.start(); lA 0_I"b2Y  
} 6YGr"Kj &  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e`1s[ ^B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lS-i9U/,>  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", K"$ky,tU  
nEndPos = " + nFileLength); E9-'!I!  
// fileSplitterFetch[nPos.length-1].start(); IjAity.Xrq  
v("vUqhx2+  
*sVxjZvV  
//等待子线程结束 !$# 4D&T  
//int count = 0; XPTB,1g+f  
//是否结束while循环 ;#yz i2f  
boolean breakWhile = false; &bu`\|V  
Lb 4!N` l  
j=>G fo  
while(!bStop) @Qozud\?  
{ --)[>6)I  
write_nPos(); 4 jro4B`  
Utility.sleep(500); RE$-{i  
breakWhile = true; P~Owvs/=  
0N_Da N  
b"bj|qF~E  
for(int i=0;i<nStartPos.length;i++) +t{FF!mL  
{ `"Pd$jW  
if(!fileSplitterFetch.bDownOver) z# B) b5  
{ KrH ;o)|  
breakWhile = false; CFxs`C^  
break; c7wgjQ[   
} -.{7;6:(k  
} 8, ^UQ5x  
if(breakWhile) pl&GFf o  
break; N6'Y N10  
b1!%xdy_T  
iJeT+}  
//count++; li^E$9oWC  
//if(count>4) R8*4E0\br  
// siteStop(); XWV~6"  
} i%w'Cs0y  
PeaD]  
n\U6oJN  
System.err.println("文件下载结束!"); ly+7klQ;.  
} )\^OI:E  
catch(Exception e){e.printStackTrace ();} ?zqXHv#x  
} nr;/:[F  
4r$t}t gX  
JG4I-\+H  
//获得文件长度 4esf&-gG  
public long getFileSize() %## bg<  
{ +eg$Z]Lht  
int nFileLength = -1; iZ yhj%#  
try{ -$!`8[fM  
URL url = new URL(siteInfoBean.getSSiteURL()); 1$]4g/":o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i!@L`h!rw  
httpConnection.setRequestProperty("User-Agent","NetFox"); J*IC&jH:  
9X/c%:)\=  
h/W@R_Y  
int responseCode=httpConnection.getResponseCode(); eYLeytF]Uy  
if(responseCode>=400) 2&S*> (  
{ OB FG!.)  
processErrorCode(responseCode); QK)"-y}"g  
return -2; //-2 represent access is error *"2TT})   
} M#c.(QdF  
TL lR"L5  
I@76ABu^  
String sHeader; ?aR)dQ  
|#fqHON  
$y S7u  
for(int i=1;;i++) x<W`2Du  
{ 481J=8H  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); q{?Po;\D  
//Utility.log(in.readLine()); W7r1!/ccj  
sHeader=httpConnection.getHeaderFieldKey(i); Ju4={^#  
if(sHeader!=null) Lwm2:_\_b  
{ cPZD#";f  
if(sHeader.equals("Content-Length")) A6v<+`?  
{ o[pv.:w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {p@uH<)  
break; ve;#o<  
} a/Z >-   
} fS+Ga1CsH  
else 9 &a&O Z{  
break; 8DHohhN  
} x2/L`q"M?=  
} z'OY6  
catch(IOException e){e.printStackTrace ();} (lBgW z  
catch(Exception e){e.printStackTrace ();} b.V\E Ok  
)D?\ru H  
bAS('R;4  
Utility.log(nFileLength); |>(d^<nR^v  
Q[+&n*  
1ga.%M*  
return nFileLength; SUwSZ@l^|  
} n<\ W Vi  
UZ#Yd|'PD  
F=)9z+l#  
//保存下载信息(文件指针位置) G Xx7/X  
private void write_nPos() Ct2m l  
{ Nb;xJSlox  
try{ K8xwPoRL  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gw[\7  
output.writeInt(nStartPos.length); r#ES|  
for(int i=0;i<nStartPos.length;i++) |L|)r)t  
{ g_'F(An  
// output.writeLong(nPos); {hYH4a&Hb  
output.writeLong(fileSplitterFetch.nStartPos); T 1'8<pJ^  
output.writeLong(fileSplitterFetch.nEndPos); n-iy;L^b  
} }@Rq'VPZd  
output.close(); hwgLJY?  
} "A\.`*6  
catch(IOException e){e.printStackTrace ();} #lDf8G|ST~  
catch(Exception e){e.printStackTrace ();} Ucnj7>+"  
} A0Z<1|6r*  
?S&pq?   
i=67  
//读取保存的下载信息(文件指针位置) l-|hvv5g  
private void read_nPos() t [gz#'  
{ ` @.  
try{ I{>U7i 5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S-)mv'Al'F  
int nCount = input.readInt(); R1.No_`PHq  
nStartPos = new long[nCount]; :5 XNV6^|  
nEndPos = new long[nCount]; O7r<6(q(  
for(int i=0;i<nStartPos.length;i++) 7+^9"k7  
{ nT UKA  
nStartPos = input.readLong(); Ph[P$: 9  
nEndPos = input.readLong(); v.Fq.  
} H"v3?g`S%  
input.close(); mDJF5I  
} GJlkEWs  
catch(IOException e){e.printStackTrace ();} NyHHK8>  
catch(Exception e){e.printStackTrace ();} QP+zGXd}(  
} UuDT=_1Sh  
Twscc"mK  
NpS*]vSO  
private void processErrorCode(int nErrorCode) w[g(8 #*  
{ ~lB im$o  
System.err.println("Error Code : " + nErrorCode); pUs:r0B  
} &S\q*H=}i  
V=#L@ws  
|Ld/{&Qr  
//停止文件下载 ^a9v5hu  
public void siteStop() zk)9tm;i{  
{ I'"b3]DXG  
bStop = true; H)XHlO^  
for(int i=0;i<nStartPos.length;i++) 8<cD+Jtj  
fileSplitterFetch.splitterStop(); K@Z K@++  
1.+w&Y5   
WJH)>4M#  
} REd"}zDI  
} We^! (G  
//负责部分文件的抓取 j 8lWra\y  
**FileSplitterFetch.java O0`k6$=6r  
*/ k_A.aYe  
package NetFox; yc|j]?  
C[cNwvz  
&r0b~RwUv  
import java.io.*; $s]c'D)  
import java.net.*; WU}?8\?U%  
wd4wYk\  
-C9 _gZ  
public class FileSplitterFetch extends Thread { P%Fkd3e+  
\k6Ho?PL  
.(!> *ka|  
String sURL; //File URL m @K5eh  
long nStartPos; //File Snippet Start Position k!/"J ;  
long nEndPos; //File Snippet End Position p h[ ^ve  
int nThreadID; //Thread's ID d',OQ,~{  
boolean bDownOver = false; //Downing is over } Qjp,(ye  
boolean bStop = false; //Stop identical e}qG_*  
FileAccessI fileAccessI = null; //File Access interface >BC?% |l  
^X$k<nA;  
"^A4!.  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B1]5%B  
{ ?y( D_NtL  
this.sURL = sURL; ,3^gB,ka  
this.nStartPos = nStart; _c}@Fi+E  
this.nEndPos = nEnd; ,X Zo0 !  
nThreadID = id; u!in>]^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _I;+p eq  
} dQfVdqg  
}{Y)[w#R  
d/>owCwQ  
public void run() RhM]OJd'  
{ #BQ7rF7CNE  
while(nStartPos < nEndPos && !bStop) voRr9E*n  
{ y~)rZ-eSB  
R:+2}kS5e{  
x\qS|q\N  
try{ }]w/`TF  
URL url = new URL(sURL); 6< x0e;>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); # 4E@y<l$  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2ye^mJ17  
String sProperty = "bytes="+nStartPos+"-"; J[ 9yQ  
httpConnection.setRequestProperty("RANGE",sProperty); %JBFG.+  
Utility.log(sProperty); ZA@QP1  
HJpkR<h  
h>v;1Q O9D  
InputStream input = httpConnection.getInputStream(); K5U=%z  
//logResponseHead(httpConnection); $YvT* T$_  
O!+LM{> F  
(fON\)l  
byte[] b = new byte[1024]; ^p#f B4z  
int nRead; 6 W/S?F~{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) O_8ERxj g]  
{ 'Z LGt#  
nStartPos += fileAccessI.write(b,0,nRead); @MIBW)P<  
//if(nThreadID == 1) a' "4:(L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SX)giQLU  
} l1^/Q~u  
l,}{Y4\G  
82F q}N <  
Utility.log("Thread " + nThreadID + " is over!"); V6l*!R  
bDownOver = true; }5gAxR,  
//nPos = fileAccessI.write (b,0,nRead); X%W_cb2  
} O/\L0\T  
catch(Exception e){e.printStackTrace ();} [.DSY[!8U  
} WjZJQK  
} o)'u%m  
zI/)#^SQ  
Q!/<=95E  
//打印回应的头信息 q;3,}emg  
public void logResponseHead(HttpURLConnection con) G)\s{qk  
{ $Gb] K{e  
for(int i=1;;i++) "'H$YhY]  
{ w)-@?jN  
String header=con.getHeaderFieldKey(i); (g,lDU[=  
if(header!=null) ^,zE Nqg7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Mw!?2G[|  
Utility.log(header+" : "+con.getHeaderField(header)); fLK*rK^{"  
else \3dM A_5  
break; A0.) =q  
} ul~>eZ  
} hGi"=Oud2  
 mfOr+   
H=]$9ZH!  
public void splitterStop() "~x\bSY  
{ RWmQP%A}aw  
bStop = true; h.c<A{[I6c  
} :T3I"  
vPEL'mw/3#  
{snLiCl  
} 7uJy<O  
GutH}Kz"&  
XNwY\y  
/* Z"Z&X0O j  
**FileAccess.java 6}mbj=E`  
*//文件访问(定位,写) P8!Vcy938  
package NetFox; rb%P30qc4  
import java.io.*; !o~% F5|t  
o:#l r{  
Vnuz! 6.  
public class FileAccessI implements Serializable{ d.tjLeY  
2D`@$)KL  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )c5 M;/s  
RandomAccessFile oSavedFile; aWek<Y~+  
long nPos; t/WauY2JUC  
a*hOT_;#  
/Ik_U?$*  
public FileAccessI() throws IOException `kIzT!HX  
{ o!L1Qrh  
this("",0); Zoj.F  
} s`xp6\$  
> C{^{?~u  
o%X_V!B{V  
public FileAccessI(String sName,long nPos) throws IOException >x@]w sj  
{ <ro0}%-z>M  
oSavedFile = new RandomAccessFile(sName,"rw"); 8#'<SB  
this.nPos = nPos; ~\4l*$3(^  
oSavedFile.seek(nPos); AuUT 'E@E  
} E4[ |=<  
1;3oGuHj8  
"C.'_H!Ex  
public synchronized int write(byte[] b,int nStart,int nLen) wx -NUTRim  
{ }$#e&&)n  
int n = -1; J}EQ_FC"$  
try{ QE84l  
oSavedFile.write(b,nStart,nLen); A?|KA<&m#u  
n = nLen; LP_d}ve  
} 9_ JK.  
catch(IOException e) !1+L0,I6  
{ #9O *@  
e.printStackTrace (); hJ.XG<?]$  
} YNc%[S[u^1  
2/=CrK  
K6~N{:.s  
return n; ^~-i>gTD  
} ]8ua>1XS  
kLMg|48fdI  
[Av87!kJ!X  
} MHVqRYz  
0z&3jWWY@  
Y oNg3  
/* iU9de  
**SiteInfoBean.java jC ,foqL  
*/ . l RW  
package NetFox; pA='(G  
|@]J*Kh  
T9KzVxHp5  
public class SiteInfoBean { vrm[sP  
LT!B]y  
oc?,8I[P5  
private String sSiteURL; //Site's URL t9&)9,my  
private String sFilePath; //Saved File's Path ! 1C3{  
private String sFileName; //Saved File's Name zBay 3a  
private int nSplitter; //Count of Splited Downloading File b=:AFs{  
F)j-D(c4  
e{:P!r aM  
public SiteInfoBean() 6/hY[a!  
{//nSplitter的缺省值为5 24Z7;'  
//default value of nSplitter is 5 ,IA0n79  
this("","","",5); _xI'p6C  
} yX$I<L<Suz  
+Q If7=  
apa~Is1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) T.<er iv  
{ (u@[}!  
sSiteURL= sURL; GbwcbfH  
sFilePath = sPath; <_uLf9j a  
sFileName = sName; S h=E.!  
this.nSplitter = nSpiltter; Ym(^i h  
jRm:9`.Q  
O}MY:6Pe  
} Z%D*2wm4  
.S`Ue,H  
r7c(/P^$G  
public String getSSiteURL() =#&K\  
{ Ht5 %fcD  
return sSiteURL; j.uN`cU!  
} *SzP7]1m  
A5!j rSyv  
SGZOfTcY  
public void setSSiteURL(String value) Z 7t0=U  
{ pL]C]HGv  
sSiteURL = value; R,C)|*ef  
} 0AY23/  
7B_;YT  
0L $v7, 5  
public String getSFilePath() ' jZ2^  
{ S5@/;T  
return sFilePath; d;|e7$F'  
} .6 !IO^`[  
$yIcut7  
df nmUE  
public void setSFilePath(String value) =$}P'[V  
{ @/lLL GrZ"  
sFilePath = value; n&i WYECz  
} *DLv$/(0  
'&W`x5`t  
CM>/b3nOW  
public String getSFileName() 'X_iiR8n@p  
{ U`,&Q ]  
return sFileName; i)1E[jc{p!  
} u'd+:uH  
z:^Kr"=n  
>a%NC'~rc  
public void setSFileName(String value) LbJ tU !  
{ +e)So+.W  
sFileName = value; /&$'v:VB  
} R$K.;  
i 6kW"5t  
yrdJX  
public int getNSplitter() Fla[YWS  
{ N;F1Z-9  
return nSplitter; _0)#-L>xKF  
} H.7gSB1  
{v+i!a'+  
wHBkaPO!  
public void setNSplitter(int nCount)  uw LT$  
{ //JF$o=)D  
nSplitter = nCount; *wwLhweQ5W  
} (i|`PA  
} R# 8D}5[&  
doFp53NhV  
3LG}x/l  
/* @?aNvWeavH  
**Utility.java 8!TbJVR  
*/  )"&-vg<  
package NetFox; .'lc[iI9)d  
GLwL'C'591  
N Rcg~Nu  
public class Utility { 9'3bzhT$  
!#rZ eDmw  
<.l5>mgkCw  
public Utility() 56G5JSB=\  
{ MQQiQ 2  
W$EX6jTGI  
u7^Z7; J  
} q .tVNKy%  
VDPqI+z  
//线程睡眠 Fy`VQ\%7t  
public static void sleep(int nSecond) zO2<Igb  
{ bsr  
try{ U> e@m?  
Thread.sleep(nSecond); Wxjk}&+pVa  
} vD:.1,72  
catch(Exception e) n-Dr/c4  
{ y3 LWh}~E  
e.printStackTrace (); cC"7Vt9b  
} j+_g37$:  
} :7W5R  
eP &K]#  
//日志 tK g%5;v  
public static void log(String sMsg) xtpD/,2  
{ twf;{lZ(  
System.err.println(sMsg); xdYjl.f  
} 2J9eeN  
6@H& S  
,m3AVHa*G  
public static void log(int sMsg) I #1_  
{ }9Y='+.%^  
System.err.println(sMsg); U!3nn#!yE  
} +(PtOo.  
} GZI[qKDfB  
YX^{lD1Jj  
5kC#uk  
/* "D3JdyO_S  
**TestMethod.java A.35WGu&:  
*/ qpp:h_E  
package NetFox; YV! !bI  
oJ6 d:  
"Hg n2o.;5  
public class TestMethod { y,Dfqt  
6TfXz2D'J  
s Uj#:X  
public TestMethod() yQou8P=%  
{ ///xx/weblogic60b2_win.exe JN|<R%hy  
try{ B-@f.NO/s  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #GWQ]r?  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >4h4t/G  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;R 2(Gb  
fileFetch.start(); ;GH(A=}/Y  
} V#3VRh  
catch(Exception e){e.printStackTrace ();} 2cy{d|c  
;uba  
)>TA|W]@  
} K =7(=Y{  
jg%D G2  
~PoGuj2wA  
public static void main(String[] args) Dt r'X@U  
{ ve K  
new TestMethod(); 9^c_^-8n<}  
} V!ajD!00  
} fl)Oto7  
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