在Java中尝试使用多个资源
我是在Java中尝试使用多个资源,java,try-with-resources,autocloseable,Java,Try With Resources,Autocloseable,我是Java8新手,我想知道,对于AutoCloseable资源,我是否必须为每个资源添加try,否则它将与上面的代码一起工作 try (Connection conn = getConnection();) { Statement stmt = conn.createStatement(); ResultSet rset = stmt.executeQuery(sql); while (rset.next()) {
Java8
新手,我想知道,对于AutoCloseable
资源,我是否必须为每个资源添加try
,否则它将与上面的代码一起工作
try (Connection conn = getConnection();) {
Statement stmt = conn.createStatement();
ResultSet rset = stmt.executeQuery(sql);
while (rset.next()) {
TelefonicaDataVO vo = new TelefonicaDataVO();
vo.setTelefonicaDataId(rset.getString("Telefonica_PSD_ID"));
vo.setReceptionDate(nvl(rset.getTimestamp("CREATION_DATE")));
vo.setMessage(nvl(rset.getString("MESSAGE")));
ret.add(vo);
}
}
Try with resources可以与多个资源一起使用,方法是在Try
块中声明所有资源,而java 7中引入的此功能不在java 8中,如果您有多个资源,则可以给出如下所示
try (
java.util.zip.ZipFile zf =
new java.util.zip.ZipFile(zipFileName);
java.io.BufferedWriter writer =
java.nio.file.Files.newBufferedWriter(outputFilePath, charset)
) {
// Enumerate each entry
for (java.util.Enumeration entries =
zf.entries(); entries.hasMoreElements();) {
// Get the entry name and write it to the output file
String newLine = System.getProperty("line.separator");
String zipEntryName =
((java.util.zip.ZipEntry)entries.nextElement()).getName() +
newLine;
writer.write(zipEntryName, 0, zipEntryName.length());
}
}
在本例中,try with resources
语句包含两个用分号分隔的声明:ZipFile和BufferedWriter。当直接跟随它的代码块终止时,无论是正常终止还是由于异常终止,BufferedWriter和ZipFile对象的close方法都会按此顺序自动调用请注意,资源的close方法的调用顺序与其创建顺序相反。
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