How to Use ParameterMetaData to Learn Parameter Information?
In the following example, it shows various methods of the ParameterMetaData object are used to display information about the type and mode of the parameters that are contained within a stored procedure.
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ParameterMetaData;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;
public class JDBCPrepareMetaData {
private static final String DBURL =
"jdbc:mysql://localhost:3306/mydb?user=usr&password=sql"
+"&useUnicode=true&characterEncoding=UTF-8";
private static final String DBDRIVER = "org.gjt.mm.mysql.Driver";
static {
try {
Class.forName(DBDRIVER).newInstance();
} catch (Exception e){
e.printStackTrace();
}
}
private static Connection getConnection()
{
Connection connection = null;
try {
connection = DriverManager.getConnection(DBURL);
}
catch (Exception e) {
e.printStackTrace();
}
return connection;
}
public static void createEmployees()
{
Connection con = getConnection();
Statement stmt =null;
String createString;
createString = "CREATE TABLE `mydb`.`employees` ("+
"`EmployeeID` int(10) unsigned NOT NULL default '0',"+
"`Name` varchar(45) collate utf8_unicode_ci NOT NULL default '',"+
"`Office` varchar(10) collate utf8_unicode_ci NOT NULL default '',"+
"`CreateTime` timestamp NOT NULL default CURRENT_TIMESTAMP,"+
"PRIMARY KEY (`EmployeeID`)"+
") ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;";
try {
stmt = con.createStatement();
stmt.executeUpdate(createString);
} catch(SQLException ex) {
System.err.println("SQLException: " + ex.getMessage());
}
finally {
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
if (con != null) {
try {
con.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
}
}
private static void dropEmployees()
{
Connection con = getConnection();
Statement stmt =null;
String createString;
createString = "DROP TABLE IF EXISTS `mydb`.`employees`;";
try {
stmt = con.createStatement();
stmt.executeUpdate(createString);
} catch(SQLException ex) {
System.err.println("SQLException: " + ex.getMessage());
}
finally {
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
if (con != null) {
try {
con.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
}
}
private static void insertEmployee()
{
Connection con = getConnection();
Statement stmt = null;
try {
stmt = con.createStatement();
stmt.addBatch("INSERT INTO employees(EmployeeID, Name, Office) "
+ "VALUES(1001, 'David Walker', 'HQ101')");
stmt.addBatch("INSERT INTO employees(EmployeeID, Name, Office) "
+ "VALUES(1002, 'Paul Walker', 'HQ202')");
stmt.addBatch("INSERT INTO employees(EmployeeID, Name, Office) "
+ "VALUES(1003, 'Scott Warner', 'HQ201')");
int [] updateCounts = stmt.executeBatch();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
finally {
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
if (con != null) {
try {
con.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
}
}
private static void dropProcedure() {
Connection con = getConnection();
Statement stmt =null;
try {
stmt = con.createStatement();
stmt.execute("DROP PROCEDURE IF EXISTS `mydb`.`WhoAreThey`");
} catch(SQLException ex) {
System.err.println("SQLException: " + ex.getMessage());
}
finally {
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
if (con != null) {
try {
con.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
}
}
private static void createProcedure() {
Connection con = getConnection();
Statement stmt =null;
try {
stmt = con.createStatement();
stmt.execute("CREATE PROCEDURE `WhoAreThey`(" +
"OUT error VARCHAR(128)," +
"IN office VARCHAR(10)) " +
"BEGIN "+
"SET error = NULL; "+
"IF office IS NULL THEN "+
"SET error = 'You need to pass in an office number'; "+
"ELSE "+
" SELECT EmployeeID, Name FROM employees " +
" WHERE office = office; "+
"END IF; "+
"END");
} catch(SQLException ex) {
System.err.println("SQLException: " + ex.getMessage());
}
finally {
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
if (con != null) {
try {
con.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
}
}
public static void getParameterMetaData() {
Connection con = getConnection();
PreparedStatement stmt = null;
try {
stmt = con.prepareStatement("INSERT INTO " +
employees(EmployeeID, Name, Office) " +
"VALUES(?,?,?)");
ParameterMetaData pmd = stmt.getParameterMetaData();
int count = pmd.getParameterCount();
for (int i = 1; i <= count; i++) {
System.out.println("Name: " + pmd.getParameterType(i));
System.out.println("TYPE: " + pmd.getParameterTypeName(i));
String mode = "";
switch(pmd.getParameterMode(i)) {
case ParameterMetaData.parameterModeIn:
mode = "IN";
break;
case ParameterMetaData.parameterModeInOut:
mode = "IN/OUT";
break;
case ParameterMetaData.parameterModeOut:
mode = "OUT";
break;
case ParameterMetaData.parameterModeUnknown:
mode = "UNKNOWN";
break;
}
System.out.println("MODE: " + mode);
}
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
finally {
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
if (con != null) {
try {
con.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
}
}
public static void getProcedureParameterMetaData() {
Connection con = getConnection();
CallableStatement cs = null;
try {
cs = con.prepareCall("{call WhoAreThey(?,?)}");
ParameterMetaData pmd = cs.getParameterMetaData();
int count = pmd.getParameterCount();
for (int i = 1; i <= count; i++) {
System.out.println("Name: " + pmd.getParameterType(i));
System.out.println("TYPE: " + pmd.getParameterTypeName(i));
String mode = "";
switch(pmd.getParameterMode(i)) {
case ParameterMetaData.parameterModeIn:
mode = "IN";
break;
case ParameterMetaData.parameterModeInOut:
mode = "IN/OUT";
break;
case ParameterMetaData.parameterModeOut:
mode = "OUT";
break;
case ParameterMetaData.parameterModeUnknown:
mode = "UNKNOWN";
break;
}
System.out.println("MODE: " + mode);
}
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
finally {
if (cs != null) {
try {
cs.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
if (con != null) {
try {
con.close();
} catch (SQLException e) {
System.err.println("SQLException: " + e.getMessage());
}
}
}
}
public static void main(String[] args) {
dropProcedure();
dropEmployees();
createEmployees();
insertEmployee();
getParameterMetaData();
System.out.println("Call Procedure.....");
createProcedure();
getProcedureParameterMetaData();
}
}
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