如何在 Java 中编写命名参数化查询

How To Write Named Parameterized Query In Java

在java中，对于大查询，创建参数化查询并不容易，因为JAVA JDBC API接口PreparedStatement只支持通过索引传递参数。 

为了克服这个限制，我们将创建自定义类，使我们能够按名称将参数传递给查询。让我们看看手头的问题是什么，然后我们将讨论解决方案。

为什么我们需要参数化查询？

在 Java 中，要执行 sql 查询，我们必须创建语句，然后我们可以执行该语句以从数据库中选择、插入、更新或删除数据。但是，不推荐这种方法，因为 java 语句不带任何参数，因此无法防止 SQL 注入。

/*
 * Here, we inserted static values in query. In your case these values might come from user input.
 * Here, we are directly concatinating the values in the query. Hence, It's not SQL injection safe.  
 */ 
String sqlQuery = " INSERT INTO employee (id, name, designation, salary)"
                + " VALUES('1', 'Dwayne Johnson', 'Project Manager', '250000')";
Statement stmt = conn.createStatement();
stmt.executeUpdate(sqlQuery);
stmt.close();

为了防止 SQL 注入，我们必须编写参数化查询。要在 java 中创建参数化查询，我们有 PreparedStatement。它可以通过在查询中传递问号 (?) 来获取参数，然后将每个问号索引替换为所需的值。

/*
 * Here, we assigned static values in parameter. In your case these values might come from user input.
 * Here, we are not directly concatinating the values in the query. Hence, It's SQL injection safe. 
 */ 
String sqlQuery = " INSERT INTO employee (id, name, designation, salary)"
                + " VALUES(?, ?, ?, ?)";
PreparedStatement prepStmt = conn.prepareStatement(sqlQuery);
prepStmt.setLong(1, 1); 
prepStmt.setString(2, "Dwayne Jhonson");
prepStmt.setString(3, "Team Leader");
prepStmt.setDouble(4, 10000);
prepStmt.executeUpdate();
prepStmt.close();

为什么我们需要命名参数化查询？

正如您在上面的示例中看到的，PreparedStatement 使用问号的索引将参数传递给查询。需要时间，因为您必须计算索引以传递值，如果您的查询中有太多列来计算查询中每列的索引，情况会变得更糟。如果我们可以做这样的事情—— 

/*
 * This code is just to show requirement. PreparedStatement in java JDBC API does not support this syntax to set parameters
 */ 
String sqlQuery = " INSERT INTO employee (id, name, designation, salary)"
                + " VALUES(:id, :name, :designation, :salary)";
PreparedStatement prepStmt = conn.prepareStatement(sqlQuery);
prepStmt.setLong("id", 1);
prepStmt.setString("name", "Dwayne Jhonson");
prepStmt.setString("designation", "Team Leader");
prepStmt.setDouble("salary", 10000);
prepStmt.executeUpdate();
prepStmt.close();

但是，PreparedStatement 不支持按名称设置参数。因此，我们必须创建自定义的 PreparedStatement 类，该类将为我们提供按名称设置参数的功能。

在一分钟内创建您的第一个命名参数化查询

下面，我展示了我为编写参数化查询而创建的两个自定义类 - 

• NamedPreparedStatement.java
• PreparedStatementImpl.java

只需在您的项目中创建这两个类，您就可以像这样在一分钟内创建参数化查询 - 

String sqlQuery = " INSERT INTO employee (id, name, designation, salary)"
                + " VALUES(:id, :name, :designation, :salary)";
PreparedStatement prepStmt = NamedPreparedStatement.prepareStatement(connection, sqlQuery);
prepStmt.setLong("id", 1);
prepStmt.setString("name", "Dwayne Jhonson");
prepStmt.setString("designation", "Team Leader");
prepStmt.setDouble("salary", 10000);
prepStmt.executeUpdate();
prepStmt.close();

你不需要知道这些类是如何工作的。您可以创建这些类并开始使用它们，如上例所示。但是，作为一名程序员，您应该尝试了解它是如何工作的。这种方法很简单，因为您不必计算列的索引，并且您可以随时更改列的顺序。

NamedPreparedStatement.java

package com.codemeright.namedPerameterizedQuery;

import java.math.BigDecimal;
import java.sql.Connection;
import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.sql.Time;
import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.regex.Matcher;

public class NamedPreparedStatement extends PreparedStatementImpl {

    private enum FormatType {

        NULL, BOOLEAN, BYTE, SHORT, INTEGER, LONG, FLOAT, DOUBLE, BIGDECIMAL, STRING, STRINGLIST, DATE, TIME, TIMESTAMP
    }

    private String originalSQL;
    private final List<String> lstParameters;

    public static NamedPreparedStatement prepareStatement(Connection conn, String sql) throws SQLException {
        List<String> orderedParameters = new ArrayList<String>();
        int length = sql.length();
        StringBuffer parsedQuery = new StringBuffer(length);
        boolean inSingleQuote = false;
        boolean inDoubleQuote = false;
        boolean inSingleLineComment = false;
        boolean inMultiLineComment = false;

        for (int i = 0; i < length; i++) {
            char c = sql.charAt(i);
            if (inSingleQuote) {
                if (c == '\'') {
                    inSingleQuote = false;
                }
            } else if (inDoubleQuote) {
                if (c == '"') {
                    inDoubleQuote = false;
                }
            } else if (inMultiLineComment) {
                if (c == '*' && sql.charAt(i + 1) == '/') {
                    inMultiLineComment = false;
                }
            } else if (inSingleLineComment) {
                if (c == '\n') {
                    inSingleLineComment = false;
                }
            } else if (c == '\'') {
                inSingleQuote = true;
            } else if (c == '"') {
                inDoubleQuote = true;
            } else if (c == '/' && sql.charAt(i + 1) == '*') {
                inMultiLineComment = true;
            } else if (c == '-' && sql.charAt(i + 1) == '-') {
                inSingleLineComment = true;
            } else if (c == ':' && i + 1 < length && Character.isJavaIdentifierStart(sql.charAt(i + 1))) {
                int j = i + 2;
                while (j < length && Character.isJavaIdentifierPart(sql.charAt(j))) {
                    j++;
                }
                String name = sql.substring(i + 1, j);
                orderedParameters.add(name);
                c = '?';
                i += name.length();
            }
            parsedQuery.append(c);
        }

        return new NamedPreparedStatement(conn.prepareStatement(parsedQuery.toString()), sql, orderedParameters);
    }

    private NamedPreparedStatement(PreparedStatement preparedStatement, String originalSQL, List<String> orderedParameters) {
        super(preparedStatement);
        this.originalSQL = originalSQL.trim();
        this.lstParameters = orderedParameters;
    }

    private Collection<Integer> getParameterIndexes(String parameter) {
        Collection<Integer> indexes = new ArrayList<Integer>();
        for (int i = 0; i < lstParameters.size(); i++) {
            if (lstParameters.get(i).equalsIgnoreCase(parameter)) {
                indexes.add(i + 1);
            }
        }
        if (indexes.isEmpty()) {
            throw new IllegalArgumentException(String.format("SQL statement doesn't contain the parameter '%s'",
                    parameter));
        }
        return indexes;
    }

    public void setNull(String parameter, int sqlType) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setNull(i, sqlType);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((String) null, FormatType.NULL)));
        }
    }

    public void setBoolean(String parameter, boolean x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setBoolean(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((Boolean) x, FormatType.BOOLEAN)));
        }
    }

    public void setByte(String parameter, byte x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setByte(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((Byte) x, FormatType.BYTE)));
        }
    }

    public void setShort(String parameter, short x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setShort(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((Short) x, FormatType.SHORT)));
        }
    }

    public void setInt(String parameter, int x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setInt(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((Integer) x, FormatType.INTEGER)));
        }
    }

    public void setLong(String parameter, long x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setLong(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((Long) x, FormatType.LONG)));
        }
    }

    public void setFloat(String parameter, float x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setFloat(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((Float) x, FormatType.FLOAT)));
        }
    }

    public void setDouble(String parameter, double x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setDouble(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((Double) x, FormatType.DOUBLE)));
        }
    }

    public void setBigDecimal(String parameter, BigDecimal x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setBigDecimal(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((BigDecimal) x, FormatType.BIGDECIMAL)));
        }
    }

    public void setString(String parameter, String x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setString(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((String) x, FormatType.STRING)));
        }
    }

    public void setBytes(String parameter, byte[] x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setBytes(i, x);
            String fval = "";
            for (int j = 0; j < x.length; j++) {
                fval += (char) x[j] + ",";
            }
            if (fval.endsWith(",")) {
                fval = fval.substring(0, fval.length() - 1);
            }
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((String) fval, FormatType.STRING)));
        }
    }

    public void setDate(String parameter, Date x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setDate(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((Date) x, FormatType.DATE)));
        }
    }

    public void setTime(String parameter, Time x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setTime(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((Time) x, FormatType.TIME)));
        }
    }

    public void setTimestamp(String parameter, Timestamp x) throws SQLException {
        for (Integer i : getParameterIndexes(parameter)) {
            getPreparedStatement().setTimestamp(i, x);
            this.originalSQL = this.originalSQL.replaceFirst("(?i):" + parameter, Matcher.quoteReplacement(format((Timestamp) x, FormatType.TIMESTAMP)));
        }
    }

    public String getQuery() {
        return this.originalSQL.trim();
    }

    private String format(Object o, FormatType type) {
        String returnParam = "";
        try {
            switch (type) {
                case NULL:
                    returnParam = "NULL";
                    break;
                case BIGDECIMAL:
                    returnParam = ((o == null) ? "NULL" : "'" + ((BigDecimal) o).toString() + "'");
                    break;
                case BOOLEAN:
                    returnParam = ((o == null) ? "NULL" : "'" + (((Boolean) o == Boolean.TRUE) ? "1" : "0") + "'");
                    break;
                case BYTE:
                    returnParam = ((o == null) ? "NULL" : "'" + ((Byte) o).intValue() + "'");
                    break;
                case DATE:
                    returnParam = ((o == null) ? "NULL" : "'" + new SimpleDateFormat("yyyy-MM-dd").format((Date) o) + "'");
                    break;
                case DOUBLE:
                    returnParam = ((o == null) ? "NULL" : "'" + ((Double) o).toString() + "'");
                    break;
                case FLOAT:
                    returnParam = ((o == null) ? "NULL" : "'" + ((Float) o).toString() + "'");
                    break;
                case INTEGER:
                    returnParam = ((o == null) ? "NULL" : "'" + ((Integer) o).toString() + "'");
                    break;
                case LONG:
                    returnParam = ((o == null) ? "NULL" : "'" + ((Long) o).toString() + "'");
                    break;
                case SHORT:
                    returnParam = ((o == null) ? "NULL" : "'" + ((Short) o).toString() + "'");
                    break;
                case STRING:
                    returnParam = ((o == null) ? "NULL" : "'" + o.toString() + "'");
                    break;
                case STRINGLIST:
                    returnParam = ((o == null) ? "NULL" : "'" + o.toString() + "'");
                    break;
                case TIME:
                    returnParam = ((o == null) ? "NULL" : "'" + new SimpleDateFormat("hh:mm:ss a").format(o) + "'");
                    break;
                case TIMESTAMP:
                    returnParam = ((o == null) ? "NULL" : "'" + new SimpleDateFormat("yyyy-MM-dd hh:mm:ss a").format(o) + "'");
                    break;
                default:
                    break;
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return returnParam.trim();
    }
}

PreparedStatementImpl.java

package com.codemeright.namedPerameterizedQuery;

import java.io.InputStream;
import java.io.Reader;
import java.math.BigDecimal;
import java.net.URL;
import java.sql.Array;
import java.sql.Blob;
import java.sql.Clob;
import java.sql.Connection;
import java.sql.Date;
import java.sql.NClob;
import java.sql.ParameterMetaData;
import java.sql.PreparedStatement;
import java.sql.Ref;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.RowId;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.SQLXML;
import java.sql.Time;
import java.sql.Timestamp;
import java.util.Calendar;

class PreparedStatementImpl implements PreparedStatement {

    private final PreparedStatement preparedStatement;

    protected PreparedStatement getPreparedStatement() {
        return preparedStatement;
    }

    public PreparedStatementImpl(PreparedStatement preparedStatement) {
        this.preparedStatement = preparedStatement;
    }

    @Override
    public <T> T unwrap(Class<T> iface) throws SQLException {
        return preparedStatement.unwrap(iface);
    }

    @Override
    public ResultSet executeQuery(String sql) throws SQLException {
        return preparedStatement.executeQuery(sql);
    }

    @Override
    public ResultSet executeQuery() throws SQLException {
        return preparedStatement.executeQuery();
    }

    @Override
    public boolean isWrapperFor(Class<?> iface) throws SQLException {
        return preparedStatement.isWrapperFor(iface);
    }

    @Override
    public int executeUpdate(String sql) throws SQLException {
        return preparedStatement.executeUpdate(sql);
    }

    @Override
    public int executeUpdate() throws SQLException {
        return preparedStatement.executeUpdate();
    }

    @Override
    public void setNull(int parameterIndex, int sqlType) throws SQLException {
        preparedStatement.setNull(parameterIndex, sqlType);
    }

    @Override
    public void close() throws SQLException {
        preparedStatement.close();
    }

    @Override
    public int getMaxFieldSize() throws SQLException {
        return preparedStatement.getMaxFieldSize();
    }

    @Override
    public void setBoolean(int parameterIndex, boolean x) throws SQLException {
        preparedStatement.setBoolean(parameterIndex, x);
    }

    @Override
    public void setByte(int parameterIndex, byte x) throws SQLException {
        preparedStatement.setByte(parameterIndex, x);
    }

    @Override
    public void setMaxFieldSize(int max) throws SQLException {
        preparedStatement.setMaxFieldSize(max);
    }

    @Override
    public void setShort(int parameterIndex, short x) throws SQLException {
        preparedStatement.setShort(parameterIndex, x);
    }

    @Override
    public int getMaxRows() throws SQLException {
        return preparedStatement.getMaxRows();
    }

    @Override
    public void setInt(int parameterIndex, int x) throws SQLException {
        preparedStatement.setInt(parameterIndex, x);
    }

    @Override
    public void setMaxRows(int max) throws SQLException {
        preparedStatement.setMaxRows(max);
    }

    @Override
    public void setLong(int parameterIndex, long x) throws SQLException {
        preparedStatement.setLong(parameterIndex, x);
    }

    @Override
    public void setEscapeProcessing(boolean enable) throws SQLException {
        preparedStatement.setEscapeProcessing(enable);
    }

    @Override
    public void setFloat(int parameterIndex, float x) throws SQLException {
        preparedStatement.setFloat(parameterIndex, x);
    }

    @Override
    public void setDouble(int parameterIndex, double x) throws SQLException {
        preparedStatement.setDouble(parameterIndex, x);
    }

    @Override
    public int getQueryTimeout() throws SQLException {
        return preparedStatement.getQueryTimeout();
    }

    @Override
    public void setQueryTimeout(int seconds) throws SQLException {
        preparedStatement.setQueryTimeout(seconds);
    }

    @Override
    public void setBigDecimal(int parameterIndex, BigDecimal x)
            throws SQLException {
        preparedStatement.setBigDecimal(parameterIndex, x);
    }

    @Override
    public void setString(int parameterIndex, String x) throws SQLException {
        preparedStatement.setString(parameterIndex, x);
    }

    @Override
    public void setBytes(int parameterIndex, byte[] x) throws SQLException {
        preparedStatement.setBytes(parameterIndex, x);
    }

    @Override
    public void cancel() throws SQLException {
        preparedStatement.cancel();
    }

    @Override
    public SQLWarning getWarnings() throws SQLException {
        return preparedStatement.getWarnings();
    }

    @Override
    public void setDate(int parameterIndex, Date x) throws SQLException {
        preparedStatement.setDate(parameterIndex, x);
    }

    @Override
    public void setTime(int parameterIndex, Time x) throws SQLException {
        preparedStatement.setTime(parameterIndex, x);
    }

    @Override
    public void clearWarnings() throws SQLException {
        preparedStatement.clearWarnings();
    }

    @Override
    public void setCursorName(String name) throws SQLException {
        preparedStatement.setCursorName(name);
    }

    @Override
    public void setTimestamp(int parameterIndex, Timestamp x)
            throws SQLException {
        preparedStatement.setTimestamp(parameterIndex, x);
    }

    @Override
    public void setAsciiStream(int parameterIndex, InputStream x, int length)
            throws SQLException {
        preparedStatement.setAsciiStream(parameterIndex, x, length);
    }

    @Override
    public boolean execute(String sql) throws SQLException {
        return preparedStatement.execute(sql);
    }

    @Deprecated
    @Override
    public void setUnicodeStream(int parameterIndex, InputStream x, int length)
            throws SQLException {
        preparedStatement.setUnicodeStream(parameterIndex, x, length);
    }

    @Override
    public ResultSet getResultSet() throws SQLException {
        return preparedStatement.getResultSet();
    }

    @Override
    public void setBinaryStream(int parameterIndex, InputStream x, int length)
            throws SQLException {
        preparedStatement.setBinaryStream(parameterIndex, x, length);
    }

    @Override
    public int getUpdateCount() throws SQLException {
        return preparedStatement.getUpdateCount();
    }

    @Override
    public boolean getMoreResults() throws SQLException {
        return preparedStatement.getMoreResults();
    }

    @Override
    public void clearParameters() throws SQLException {
        preparedStatement.clearParameters();
    }

    @Override
    public void setObject(int parameterIndex, Object x, int targetSqlType)
            throws SQLException {
        preparedStatement.setObject(parameterIndex, x, targetSqlType);
    }

    @Override
    public void setFetchDirection(int direction) throws SQLException {
        preparedStatement.setFetchDirection(direction);
    }

    @Override
    public int getFetchDirection() throws SQLException {
        return preparedStatement.getFetchDirection();
    }

    @Override
    public void setObject(int parameterIndex, Object x) throws SQLException {
        preparedStatement.setObject(parameterIndex, x);
    }

    @Override
    public void setFetchSize(int rows) throws SQLException {
        preparedStatement.setFetchSize(rows);
    }

    @Override
    public int getFetchSize() throws SQLException {
        return preparedStatement.getFetchSize();
    }

    @Override
    public int getResultSetConcurrency() throws SQLException {
        return preparedStatement.getResultSetConcurrency();
    }

    @Override
    public boolean execute() throws SQLException {
        return preparedStatement.execute();
    }

    @Override
    public int getResultSetType() throws SQLException {
        return preparedStatement.getResultSetType();
    }

    @Override
    public void addBatch(String sql) throws SQLException {
        preparedStatement.addBatch(sql);
    }

    @Override
    public void clearBatch() throws SQLException {
        preparedStatement.clearBatch();
    }

    @Override
    public void addBatch() throws SQLException {
        preparedStatement.addBatch();
    }

    @Override
    public int[] executeBatch() throws SQLException {
        return preparedStatement.executeBatch();
    }

    @Override
    public void setCharacterStream(int parameterIndex, Reader reader, int length)
            throws SQLException {
        preparedStatement.setCharacterStream(parameterIndex, reader, length);
    }

    @Override
    public void setRef(int parameterIndex, Ref x) throws SQLException {
        preparedStatement.setRef(parameterIndex, x);
    }

    @Override
    public void setBlob(int parameterIndex, Blob x) throws SQLException {
        preparedStatement.setBlob(parameterIndex, x);
    }

    @Override
    public void setClob(int parameterIndex, Clob x) throws SQLException {
        preparedStatement.setClob(parameterIndex, x);
    }

    @Override
    public Connection getConnection() throws SQLException {
        return preparedStatement.getConnection();
    }

    @Override
    public void setArray(int parameterIndex, Array x) throws SQLException {
        preparedStatement.setArray(parameterIndex, x);
    }

    @Override
    public ResultSetMetaData getMetaData() throws SQLException {
        return preparedStatement.getMetaData();
    }

    @Override
    public boolean getMoreResults(int current) throws SQLException {
        return preparedStatement.getMoreResults(current);
    }

    @Override
    public void setDate(int parameterIndex, Date x, Calendar cal)
            throws SQLException {
        preparedStatement.setDate(parameterIndex, x, cal);
    }

    @Override
    public ResultSet getGeneratedKeys() throws SQLException {
        return preparedStatement.getGeneratedKeys();
    }

    @Override
    public void setTime(int parameterIndex, Time x, Calendar cal)
            throws SQLException {
        preparedStatement.setTime(parameterIndex, x, cal);
    }

    @Override
    public int executeUpdate(String sql, int autoGeneratedKeys)
            throws SQLException {
        return preparedStatement.executeUpdate(sql, autoGeneratedKeys);
    }

    @Override
    public void setTimestamp(int parameterIndex, Timestamp x, Calendar cal)
            throws SQLException {
        preparedStatement.setTimestamp(parameterIndex, x, cal);
    }

    @Override
    public void setNull(int parameterIndex, int sqlType, String typeName)
            throws SQLException {
        preparedStatement.setNull(parameterIndex, sqlType, typeName);
    }

    @Override
    public int executeUpdate(String sql, int[] columnIndexes)
            throws SQLException {
        return preparedStatement.executeUpdate(sql, columnIndexes);
    }

    @Override
    public void setURL(int parameterIndex, URL x) throws SQLException {
        preparedStatement.setURL(parameterIndex, x);
    }

    @Override
    public int executeUpdate(String sql, String[] columnNames)
            throws SQLException {
        return preparedStatement.executeUpdate(sql, columnNames);
    }

    @Override
    public ParameterMetaData getParameterMetaData() throws SQLException {
        return preparedStatement.getParameterMetaData();
    }

    @Override
    public void setRowId(int parameterIndex, RowId x) throws SQLException {
        preparedStatement.setRowId(parameterIndex, x);
    }

    @Override
    public void setNString(int parameterIndex, String value)
            throws SQLException {
        preparedStatement.setNString(parameterIndex, value);
    }

    @Override
    public boolean execute(String sql, int autoGeneratedKeys)
            throws SQLException {
        return preparedStatement.execute(sql, autoGeneratedKeys);
    }

    @Override
    public void setNCharacterStream(int parameterIndex, Reader value,
            long length) throws SQLException {
        preparedStatement.setNCharacterStream(parameterIndex, value, length);
    }

    @Override
    public void setNClob(int parameterIndex, NClob value) throws SQLException {
        preparedStatement.setNClob(parameterIndex, value);
    }

    @Override
    public void setClob(int parameterIndex, Reader reader, long length)
            throws SQLException {
        preparedStatement.setClob(parameterIndex, reader, length);
    }

    @Override
    public boolean execute(String sql, int[] columnIndexes) throws SQLException {
        return preparedStatement.execute(sql, columnIndexes);
    }

    @Override
    public void setBlob(int parameterIndex, InputStream inputStream, long length)
            throws SQLException {
        preparedStatement.setBlob(parameterIndex, inputStream, length);
    }

    @Override
    public void setNClob(int parameterIndex, Reader reader, long length)
            throws SQLException {
        preparedStatement.setNClob(parameterIndex, reader, length);
    }

    @Override
    public boolean execute(String sql, String[] columnNames)
            throws SQLException {
        return preparedStatement.execute(sql, columnNames);
    }

    @Override
    public void setSQLXML(int parameterIndex, SQLXML xmlObject)
            throws SQLException {
        preparedStatement.setSQLXML(parameterIndex, xmlObject);
    }

    @Override
    public void setObject(int parameterIndex, Object x, int targetSqlType,
            int scaleOrLength) throws SQLException {
        preparedStatement.setObject(parameterIndex, x, targetSqlType, scaleOrLength);
    }

    @Override
    public int getResultSetHoldability() throws SQLException {
        return preparedStatement.getResultSetHoldability();
    }

    @Override
    public boolean isClosed() throws SQLException {
        return preparedStatement.isClosed();
    }

    @Override
    public void setPoolable(boolean poolable) throws SQLException {
        preparedStatement.setPoolable(poolable);
    }

    @Override
    public boolean isPoolable() throws SQLException {
        return preparedStatement.isPoolable();
    }

    @Override
    public void closeOnCompletion() throws SQLException {
        preparedStatement.closeOnCompletion();
    }

    @Override
    public void setAsciiStream(int parameterIndex, InputStream x, long length)
            throws SQLException {
        preparedStatement.setAsciiStream(parameterIndex, x, length);
    }

    @Override
    public boolean isCloseOnCompletion() throws SQLException {
        return preparedStatement.isCloseOnCompletion();
    }

    @Override
    public void setBinaryStream(int parameterIndex, InputStream x, long length)
            throws SQLException {
        preparedStatement.setBinaryStream(parameterIndex, x, length);
    }

    @Override
    public void setCharacterStream(int parameterIndex, Reader reader,
            long length) throws SQLException {
        preparedStatement.setCharacterStream(parameterIndex, reader, length);
    }

    @Override
    public void setAsciiStream(int parameterIndex, InputStream x)
            throws SQLException {
        preparedStatement.setAsciiStream(parameterIndex, x);
    }

    @Override
    public void setBinaryStream(int parameterIndex, InputStream x)
            throws SQLException {
        preparedStatement.setBinaryStream(parameterIndex, x);
    }

    @Override
    public void setCharacterStream(int parameterIndex, Reader reader)
            throws SQLException {
        preparedStatement.setCharacterStream(parameterIndex, reader);
    }

    @Override
    public void setNCharacterStream(int parameterIndex, Reader value)
            throws SQLException {
        preparedStatement.setNCharacterStream(parameterIndex, value);
    }

    @Override
    public void setClob(int parameterIndex, Reader reader) throws SQLException {
        preparedStatement.setClob(parameterIndex, reader);
    }

    @Override
    public void setBlob(int parameterIndex, InputStream inputStream)
            throws SQLException {
        preparedStatement.setBlob(parameterIndex, inputStream);
    }

    @Override
    public void setNClob(int parameterIndex, Reader reader) throws SQLException {
        preparedStatement.setNClob(parameterIndex, reader);
    }

}

所以，现在您已经看到了自定义类NamedParameterizedQuery.java 和 ParameterizedQueryImpl.java。 此外，您还知道如何使用上述示例中的这些类创建命名参数化查询。如果你好奇这些类是如何工作的，你可以在 debud 模式下测试它们以了解它的功能。