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http断点续传简单实现(java)

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/* gK"E4{y_@  
**SiteFileFetch.java j[YO1q*  
*/ P<gr=&  
package NetFox; w^aI1M50  
import java.io.*; UkXf)  
import java.net.*; /M8&`  
]$a,/Jt  
79Si^n1\  
public class SiteFileFetch extends Thread { K9N\E"6ZP  
XnI)s^  
095Z Z20  
SiteInfoBean siteInfoBean = null; //文件信息Bean >c 5V VA8  
long[] nStartPos; //开始位置 IgU65p  
long[] nEndPos; //结束位置 xs3t~o3y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ){{]3r  
long nFileLength; //文件长度 Snf1vH  
boolean bFirst = true; //是否第一次取文件 sa>}wz<o  
boolean bStop = false; //停止标志 ZA/:\6gm  
File tmpFile; //文件下载的临时信息 xp"5L8:C  
DataOutputStream output; //输出到文件的输出流 JRl`evTS  
mg7Q~SLL{  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 4XL]~3 c  
public SiteFileFetch(SiteInfoBean bean) throws IOException )'gO?cN  
{ C'jE'B5b  
siteInfoBean = bean; Qh. : N  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a6fqtkZ x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /6@Wm? `DB  
if(tmpFile.exists ()) H- aSLc  
{ WAt| J2  
bFirst = false; /5c;,.hm1R  
read_nPos(); ]f"l4ay@M  
} x_TtS|   
else ,k5b,}tN  
{ Q:~>$5Em5  
nStartPos = new long[bean.getNSplitter()]; 9&uWj'%ia  
nEndPos = new long[bean.getNSplitter()]; (VzabO  
} }28,fb /  
ROB/#Td  
4chSo.= 4V  
KD5}Nk)t  
} }vLK-V v  
3d@$iAw1<  
O*7Gl G  
public void run() /_G^d1T1?L  
{ ,5L[M&5  
//获得文件长度 qhiO( !jK  
//分割文件 OAiip,  
//实例FileSplitterFetch g0BJj=  
//启动FileSplitterFetch线程 s&7,gWy}BE  
//等待子线程返回 =5sUpP V(  
try{ tu6Q7CjW8  
if(bFirst) Q]}aZ4L  
{ $'2yPoR  
nFileLength = getFileSize(); Gf{FFIe(  
if(nFileLength == -1) z"C+r'39d=  
{ a:(.{z?nM  
System.err.println("File Length is not known!"); aN5w  
} DxLN{g]B  
else if(nFileLength == -2) BiUOjQC#  
{ _g(4-\  
System.err.println("File is not access!"); &_EjP hZ  
} @Gj|X>0  
else phA^ kdW  
{ $m;rOKVU  
for(int i=0;i<nStartPos.length;i++) KF[P /cFI  
{ MH>CCT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >dW~o_u'QN  
} i$A0_ZJKjZ  
for(int i=0;i<nEndPos.length-1;i++) )`ZTu -|  
{ \*V`w@  
nEndPos = nStartPos[i+1]; C?3?<FDL  
} XY;cz  
nEndPos[nEndPos.length-1] = nFileLength; ?4U|6|1  
} '}D$"2I*  
} ^=nJ,-(h_  
rU /V ~;#%  
kR0d]"dr  
//启动子线程 ]~SOGAFW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; xCOC5f5*@  
for(int i=0;i<nStartPos.length;i++) CR-6}T   
{ QJaF6>m  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V+mTo^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), JZ5N Q)sX  
nStartPos,nEndPos,i); "@JSF  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X~O2!F  
fileSplitterFetch.start(); xsq+RBJi  
} F~cvob{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gt9{u"o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); luyU!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6Y|jK< n?H  
nEndPos = " + nFileLength); ",\,lqV  
// fileSplitterFetch[nPos.length-1].start(); 4$+9Wv  
FBYA d@="2  
75t\= 6#  
//等待子线程结束 M8 E8r  
//int count = 0; ?2b*F Qe  
//是否结束while循环  ;Q;u^T`  
boolean breakWhile = false; Q-X<zn  
S1<mO-  
IQFt4{aK3  
while(!bStop) j7vp@l6`L  
{ L+}q !'8S  
write_nPos(); ptS1d$  
Utility.sleep(500); .cTK\  
breakWhile = true; 6O^'J~wiI  
\@6nRs8b|N  
(Z YGfX  
for(int i=0;i<nStartPos.length;i++) H}OOkzwrA  
{ 5Mfs)a4j.  
if(!fileSplitterFetch.bDownOver) cC_L4  
{ D2`tWRm0  
breakWhile = false; ic}M)S FD;  
break; K0#kW \4`  
} NM0[yh  
} 8#gS{   
if(breakWhile) lD;="b  
break; !H`Q^Xf}  
BTXS+mvl  
[/}y!;3iXM  
//count++; %E95R8SL  
//if(count>4) #OKzJ"g  
// siteStop(); I<q=lK  
} *RQkL'tRf  
"JLKO${ Y  
7a@%^G @!  
System.err.println("文件下载结束!"); R6ynL([xh  
} }U=|{@%  
catch(Exception e){e.printStackTrace ();}  q$$:<*Uy  
} e>-a\g  
fX,L;Se"  
X]J]7\4tF\  
//获得文件长度 7gR8Wr ^  
public long getFileSize() =(f+geA"hm  
{ 'E2\e!U/  
int nFileLength = -1; e Ir|%  
try{ !%' 1 x2?  
URL url = new URL(siteInfoBean.getSSiteURL()); }s_'q~R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1nv#Ehorg  
httpConnection.setRequestProperty("User-Agent","NetFox"); S4j`=<T,  
j +j2_\  
*t{$GBP  
int responseCode=httpConnection.getResponseCode(); !c`K zqP  
if(responseCode>=400) x/NR_~Rnk  
{ qRg^Bp'VD#  
processErrorCode(responseCode); <_HK@E<_HO  
return -2; //-2 represent access is error gO*:< B g  
} pu(a&0  
03ol!|X "9  
as1ZLfN.  
String sHeader; yub|   
D|W^PR:@h  
oT7=  
for(int i=1;;i++) SbNs#  
{  >:whNp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "HRoS#|\  
//Utility.log(in.readLine()); uqy b  
sHeader=httpConnection.getHeaderFieldKey(i); M{U{iS  
if(sHeader!=null) Ih*}1D)7  
{ ;$|[z<1RdW  
if(sHeader.equals("Content-Length")) 3PB#m.N<  
{ P@ewr}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -c-#1_X5  
break; C WJGr:}&  
} {Mc^[}9  
} bkQEfx.  
else Vy;f4;I{  
break; <MgR x9  
} 2%YtMkC5  
} > uS?Nz5/  
catch(IOException e){e.printStackTrace ();} B+G,v:)R6z  
catch(Exception e){e.printStackTrace ();} {EKzPr/  
cd36f26`"w  
0h~Iua5  
Utility.log(nFileLength); $sDvE~f0n  
N;cEf7+f  
I g/SaEF  
return nFileLength; ]Mu + DZ  
} 8r^~`rL  
pyEi@L1p  
KX e/i~AS  
//保存下载信息(文件指针位置) -aCtk$3  
private void write_nPos() d'~sy>  
{ 8}m bfu o1  
try{ <szD"p|K  
output = new DataOutputStream(new FileOutputStream(tmpFile)); nJJ9>#<g$  
output.writeInt(nStartPos.length); Nf0'>`/  
for(int i=0;i<nStartPos.length;i++) %vjLw`  
{ Mg H,"G  
// output.writeLong(nPos); \%nFCK0  
output.writeLong(fileSplitterFetch.nStartPos); `8Y& KVhu  
output.writeLong(fileSplitterFetch.nEndPos); +*2wGAT  
} o9)pOwk7;  
output.close(); Y>KRI2](<  
} -!uut7Z|  
catch(IOException e){e.printStackTrace ();} YNc] x>  
catch(Exception e){e.printStackTrace ();} }`g:) g J  
} > }#h  
&61;v@  
7Y$#* 7  
//读取保存的下载信息(文件指针位置) W2L:  
private void read_nPos() D9H(kk  
{ {R[FwB^7wJ  
try{ F|K=].  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); rn^ 7B-V  
int nCount = input.readInt(); O>)<w Ms`  
nStartPos = new long[nCount]; 2 s,[DC  
nEndPos = new long[nCount]; a []Iz8*6e  
for(int i=0;i<nStartPos.length;i++) v)|[=  
{ & 2MI(9v  
nStartPos = input.readLong(); csg:# -gE  
nEndPos = input.readLong(); K31G>k@  
} FLI\SF<  
input.close(); L,*KgLG  
} z;:c_y!f  
catch(IOException e){e.printStackTrace ();} }q1@[ aE  
catch(Exception e){e.printStackTrace ();} >C"f'!oM,j  
} p F\~T>  
)ndcBwQc"  
a!MhxM5  
private void processErrorCode(int nErrorCode) L8K= Q  
{ 5y7rY!]Bf  
System.err.println("Error Code : " + nErrorCode); #3@ Du(_n  
} 2j_YHv$I  
]3tg|? %B  
;SAurG$  
//停止文件下载 uU v yZ  
public void siteStop() &fJ92v?%^S  
{ ~F8M_  
bStop = true; `IQ01FuP  
for(int i=0;i<nStartPos.length;i++) -"qw5Y_oF?  
fileSplitterFetch.splitterStop(); 7;dTQ.%n  
Fj\}&H*+  
%,$Ms?,n`  
} t3ua5xw  
} uP<w rlW  
//负责部分文件的抓取 $mvcqn;  
**FileSplitterFetch.java ]]lgCac_U9  
*/ (4_7ICFI  
package NetFox; )3<|<jwcx  
EL!V\J`S_  
4`lt 4L  
import java.io.*; V{17iRflf  
import java.net.*; 8<(qN> R  
!@mV$nTA  
^UP!y!&N  
public class FileSplitterFetch extends Thread { )(~s-x^\z@  
o JC-?  
OgJd^  
String sURL; //File URL s(56aE  
long nStartPos; //File Snippet Start Position tydD~a  
long nEndPos; //File Snippet End Position GOJ*>GpS  
int nThreadID; //Thread's ID cU8Rm\?  
boolean bDownOver = false; //Downing is over }X{#=*$GQ  
boolean bStop = false; //Stop identical HRkO.230  
FileAccessI fileAccessI = null; //File Access interface ^)ouL25Z*2  
E"!I[  
yM$@*od  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &7* |rshZ  
{ USz |Rh  
this.sURL = sURL; ;h[p "  
this.nStartPos = nStart; oh+Q}Fa:  
this.nEndPos = nEnd; 32!jF}qpD  
nThreadID = id; V@gweci  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 F"2v5F@  
} nR)/k,3W  
1e`/N+6u  
x`8rR;N!  
public void run() >|%dN jf@Q  
{ RUcpdeo  
while(nStartPos < nEndPos && !bStop) 5/j7C>  
{ hwF9LD~^  
_2Sb?]Xn  
3xS+Pu\)  
try{ utIR\e#:B  
URL url = new URL(sURL); :V1ttRW}52  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eliT<sw8  
httpConnection.setRequestProperty("User-Agent","NetFox"); A/n-.ci  
String sProperty = "bytes="+nStartPos+"-"; i^j1 i  
httpConnection.setRequestProperty("RANGE",sProperty); 0$)CWah  
Utility.log(sProperty); 2e_ssBbb  
WP)r5;Hv`  
D BDHe-1[+  
InputStream input = httpConnection.getInputStream(); &YQ  
//logResponseHead(httpConnection); 40TS=evG  
KL:x!GsV5e  
:^7P. lhK  
byte[] b = new byte[1024]; e?W-vi%  
int nRead; '<N^u@tF7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4W7  
{ i#/,Q1yEn  
nStartPos += fileAccessI.write(b,0,nRead); 2NS(;tBB0  
//if(nThreadID == 1) 'n`+R~Kkh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ; MU8@?yN  
} C[f'1O7  
Xup rl2+  
w,hl<=:(FB  
Utility.log("Thread " + nThreadID + " is over!"); ^mWOQ*zi;  
bDownOver = true; ]IbX<  
//nPos = fileAccessI.write (b,0,nRead); {"X n`@Y  
} b~;gj^  
catch(Exception e){e.printStackTrace ();} [RtTi<F^  
} h2kb a6rwk  
} ovv<7`  
.FUws  
VO#x+u]/  
//打印回应的头信息 D$C>ZF  
public void logResponseHead(HttpURLConnection con) D^cv 8 8<  
{ N$1ZA)M  
for(int i=1;;i++)  lJaR,,  
{ j`JY3RDD  
String header=con.getHeaderFieldKey(i); W;~ f865  
if(header!=null) (S1c6~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); on?<3eED  
Utility.log(header+" : "+con.getHeaderField(header)); 2'O2n]{  
else E`#m0Q(8  
break; RLBeti>  
} x*}41;j}C  
} wf47Ulx  
A*d Pw.  
}j=UO*|  
public void splitterStop() &)UZ9r`z  
{ oNW.-gNT  
bStop = true; y %R-Oc  
} O@*7O~eO  
V_b"^911r  
5`su^  
} ,;3#}OGg  
}yQ&[Mt  
P2y`d9,Q  
/* l=EnK"aU  
**FileAccess.java =T_E]>FF9  
*//文件访问(定位,写) UQq ,Xq  
package NetFox; YU=Q`y[k  
import java.io.*; >R9Q|   
0,~f"Dyqy  
iuxI$  
public class FileAccessI implements Serializable{ *nb `DR  
<2b&AF{En  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r6 k/QZT  
RandomAccessFile oSavedFile; m]C|8b7Y  
long nPos; OIi8x? .~]  
bv %Bo4s  
yVF1*#"  
public FileAccessI() throws IOException ~Mk{2;x  
{ B4tC3r  
this("",0); F"p7&e\W|l  
} JQ5E;8J>  
&BF97%E2  
yT[CC>]l  
public FileAccessI(String sName,long nPos) throws IOException 9W^sq<tR  
{ b02V#m;Z  
oSavedFile = new RandomAccessFile(sName,"rw"); D~~"wos  
this.nPos = nPos; I,[njlO:  
oSavedFile.seek(nPos); Jo%`N#jG   
} g.L~Z1-  
^\<nOzU?  
\X3Q,\H @  
public synchronized int write(byte[] b,int nStart,int nLen) JONfNb+  
{ X#;n Gq)5  
int n = -1; 4XL$I*;4  
try{ zL8Z8eh">  
oSavedFile.write(b,nStart,nLen); "LwLTPC2  
n = nLen; i}&&rr  
} P{T\zT  
catch(IOException e) }kJfTsFS  
{ n ~c<[  
e.printStackTrace (); E[Xqyp!<  
} 0.pZlv  
SB1j$6]OR7  
DIsK+1  
return n; -DVoO2|Dv  
} u{| Q[hf[  
EC9bCd-z  
#@pgB:~lB  
} b#uNdq3  
=*0KH##%$  
"0*yD[2  
/* _#\e5bE=Z  
**SiteInfoBean.java H1bHQB  
*/ ni2GZ<1j  
package NetFox; (-}:'5|Yj  
GtuA94=!V&  
_sp, ,gz  
public class SiteInfoBean { x3>ZO.Q  
IOfxx>=3  
 W8blHw"  
private String sSiteURL; //Site's URL lF*}l  
private String sFilePath; //Saved File's Path LiG!xs  
private String sFileName; //Saved File's Name Sb4^* $uz  
private int nSplitter; //Count of Splited Downloading File /EIQMZuYp  
0Cg}yyOz  
`p!&>,lrk  
public SiteInfoBean() "*U0xnI  
{//nSplitter的缺省值为5 g 2LY~  
//default value of nSplitter is 5 qw?Wi%t(x8  
this("","","",5); M2kvj'WWq  
} @:dn\{Zsea  
PFKl6_(  
^ABt g#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |D% O`[k+  
{ @=7[KMb  
sSiteURL= sURL; "L0Q"t:  
sFilePath = sPath; *5QN:  
sFileName = sName; /3`yaYkSh  
this.nSplitter = nSpiltter; +TZVx(Z&A  
aZ,j1j0p  
~hZr1hT6L  
} 1^ijKn@6  
&lCOhP#  
/Hs\`Kg"!  
public String getSSiteURL() !V'~<&  
{ I!?)}d  
return sSiteURL; tP:ER  
} <(!~s><.  
&ggOm  
s/l>P~3=  
public void setSSiteURL(String value) <.Dg3RH  
{ q)l1tC72  
sSiteURL = value; c W1`[b  
} %{|67h  
b$eN]L   
@CtnV|  
public String getSFilePath() ]@I>OcH  
{ Z,~PW#8<&  
return sFilePath; Ez/>3:;  
} d4m@u$^1B  
#AR$'TE#  
DO 0  
public void setSFilePath(String value) R0#'t+7^  
{ \>\_OfY1W  
sFilePath = value; Pil_zQ4  
} !DM GAt\  
${5E  
aKFY&zN?  
public String getSFileName() uhm3}mWv  
{ h:AB`E1  
return sFileName; (Fj"<  
} ~c=F$M^"c  
<^w4+5sT/  
;d .gVR_V  
public void setSFileName(String value) V2S HF  
{ Q-?6o  
sFileName = value; `qV*R 2  
} FN<S agj  
l`A e&nc6  
8Sk$o.Gy  
public int getNSplitter() 0m,q3  
{ `< 82"cAT{  
return nSplitter; hK UK#xx  
} ?sW}<8\  
[VE>{4]W  
T<%%f.x[s  
public void setNSplitter(int nCount) )&$mFwf  
{ rhDiIO_  
nSplitter = nCount; [;Jq=G8&t  
} z?t75#u9.  
} goOw.~dZ'  
zGwM# -  
oh7tE$"c  
/* iOtf7.@  
**Utility.java wzF%R {;  
*/ P& h]uNu  
package NetFox; Q0%s|8Jc  
HPX JRQBE  
I uC7Hx`z  
public class Utility { cR=o!2O  
tZY6{,K%4  
;YZ'd"0v  
public Utility() C^fn[plL  
{ d[YG&.}+8j  
P @~)9W  
]2c0?f*Y7  
} AqT}^fS  
 Khh}flRy  
//线程睡眠 KJv[z   
public static void sleep(int nSecond) F+]cFx,/  
{ Ri>ZupQ6  
try{ Dqc2;>  
Thread.sleep(nSecond); U Z1Au;(|  
} -' =?Hs.  
catch(Exception e) >uxAti\  
{ 3i#'osq  
e.printStackTrace (); 2;x+#D8  
} tHEZuoi  
} (W.G&VSn)  
4N5\sdi  
//日志 /@1pm/>ZaN  
public static void log(String sMsg) Fd#Zu.Np  
{ AYAbq}'Yt  
System.err.println(sMsg); " H]R\xp  
} mRy0zN>?  
,hWuAu6.L  
{mB!mbr  
public static void log(int sMsg) }S;A%gYm  
{ w3&L 6|,  
System.err.println(sMsg); K,,'{j2#f  
} qFI19`?8E  
} &YBZuq2?  
kz G W/  
`i!fg\qnK  
/* V ONC<wC  
**TestMethod.java V@nZ_.  
*/ L9]d$ r"  
package NetFox; Fw8b^ew  
DUwms"I,%  
(o^?i2)g  
public class TestMethod { !gcea?I  
@SI,V8i  
rl x6a@MiD  
public TestMethod() QZ+G2$  
{ ///xx/weblogic60b2_win.exe /I:&P Pff  
try{ YRCOh:W*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RN$>!b/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6m@B.+1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ed+jSO0  
fileFetch.start();  6),!sO?  
} g""Ep  
catch(Exception e){e.printStackTrace ();} B}J0 d  
J06 D_'{  
yG;@S8zC  
} I]%Kd('  
0es\ j6c  
EeGTBVms  
public static void main(String[] args) _j*a5fsPU  
{ tns4e\  
new TestMethod(); i0Rj;E=:]  
} ZSr!L@S  
} xUTTRJ(\  
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