第1个回答 2021-11-08
package test2;
import java.util.Arrays;
public class test2_test6 {
int[] i;
void setI(int[] i) {
this.i = i;
}
//两种方法
//第一种,直接打印数组
String getI_value1() {
return Arrays.toString(i);
}
//第二种,循环遍历
String getI_value2() {
StringBuilder s = new StringBuilder();
for (int i_value : i) {
s.append(i_value);
s.append(" ");
}
return s.toString();
}
public static void main(String[] args) {
int[] Array = {1, 2, 3, 4, 5};
test2_test6 t2_t6 = new test2_test6();
t2_t6.setI(Array);
System.out.println("第一种方法获取值:");
System.out.println(t2_t6.getI_value1());
System.out.println("第二种方法获取值:");
System.out.println(t2_t6.getI_value2());
}
}
第5个回答 2021-11-07
我在我的prepare语句中遇到错误java.sql.SQLFeatureNotSupportedException.我正在使用Mysql数据库.
以下是我的代码.
class tmp {
public static void main(String arg[]) {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection(
"jdbc:mysql://localhost/sample", "root", "root");
PreparedStatement pst = conn
.prepareStatement("select * from userinfo where firstname in(?)");
String[] Parameter = { "user1", "Administrator" };
Array sqlArray = conn.createArrayOf("VARCHAR", Parameter);
pst.setArray(1, sqlArray);
ResultSet rs = pst.executeQuery();
while (rs.next()) {
System.out.println(rs.getInt(1));
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
解决方法:
对于Mysql –
在Mysql中无法设置数组.
而不是你可以在循环中形成(?,?,..)的查询以及设置值的相同方式.
String[] Parameter = { "user1", "Administrator" };
String query = "select * from userinfo where firstname in (";
String temp = "";
for(i = 0; i < Parameter.length; i++) {
temp += ",?";
}
temp = temp.replaceFirst(",", "");
temp += ")";
query = query + temp;
PreparedStatement pst = conn.prepareStatement(query);
所以查询变成了
select * from userinfo where firstname in (?,?)
并使用循环传递值.
对于甲骨文 –
ArrayDescriptor arrayDescriptor = ArrayDescriptor.createDescriptor("CHAR_ARRAY", conn);
String[] Parameter = { "user1", "Administrator" };
java.sql.Array sqlArray = new oracle.sql.ARRAY(arrayDescriptor, conn, content);
.
.
pstmt.setArray(1, sqlArray);
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