引用自mattjames

语句在JDBC中的使用应该100%本地化为正在使用 对于DDL (ALTER, CREATE, GRANT等)，因为这些是唯一的语句 不能接受BIND变量的类型。preparedstatement或 CallableStatements应该用于所有其他类型的语句 (DML、查询)。因为这些是接受bind的语句类型 变量。 这是一个事实，一条规则，一条法律——在任何地方都使用事先准备好的陈述。 几乎不使用语句。

They are pre-compiled (once), so faster for repeated execution of dynamic SQL (where parameters change) Database statement caching boosts DB execution performance Databases store caches of execution plans for previously executed statements. This allows the database engine to reuse the plans for statements that have been executed previously. Because PreparedStatement uses parameters, each time it is executed it appears as the same SQL, the database can reuse the previous access plan, reducing processing. Statements "inline" the parameters into the SQL string and so do not appear as the same SQL to the DB, preventing cache usage. Binary communications protocol means less bandwidth and faster comms calls to DB server Prepared statements are normally executed through a non-SQL binary protocol. This means that there is less data in the packets, so communications to the server is faster. As a rule of thumb network operations are an order of magnitude slower than disk operations which are an order of magnitude slower than in-memory CPU operations. Hence, any reduction in amount of data sent over the network will have a good effect on overall performance. They protect against SQL injection, by escaping text for all the parameter values provided. They provide stronger separation between the query code and the parameter values (compared to concatenated SQL strings), boosting readability and helping code maintainers quickly understand inputs and outputs of the query. In java, can call getMetadata() and getParameterMetadata() to reflect on the result set fields and the parameter fields, respectively In java, intelligently accepts java objects as parameter types via setObject, setBoolean, setByte, setDate, setDouble, setDouble, setFloat, setInt, setLong, setShort, setTime, setTimestamp - it converts into JDBC type format that is comprehendible to DB (not just toString() format). In java, accepts SQL ARRAYs, as parameter type via setArray method In java, accepts CLOBs, BLOBs, OutputStreams and Readers as parameter "feeds" via setClob/setNClob, setBlob, setBinaryStream, setCharacterStream/setAsciiStream/setNCharacterStream methods, respectively In java, allows DB-specific values to be set for SQL DATALINK, SQL ROWID, SQL XML, and NULL via setURL, setRowId, setSQLXML ans setNull methods In java, inherits all methods from Statement. It inherits the addBatch method, and additionally allows a set of parameter values to be added to match the set of batched SQL commands via addBatch method. In java, a special type of PreparedStatement (the subclass CallableStatement) allows stored procedures to be executed - supporting high performance, encapsulation, procedural programming and SQL, DB administration/maintenance/tweaking of logic, and use of proprietary DB logic & features

不能在语句中使用clob。

And: (OraclePreparedStatement) ps

我遵循了这个问题的所有答案，使用- Statement(但有SQL注入)将工作的遗留代码更改为使用PreparedStatement的解决方案，由于对Statement周围的语义理解不佳，代码要慢得多。addBatch(String sql) & PreparedStatement.addBatch()。

所以我在这里列出了我的情况，这样其他人就不会犯同样的错误。

我的设想是

Statement statement = connection.createStatement();

for (Object object : objectList) {
    //Create a query which would be different for each object 
    // Add this query to statement for batch using - statement.addBatch(query);
}
statement.executeBatch();

所以在上面的代码中，我有数千个不同的查询，都添加到相同的语句中，这段代码工作得更快，因为语句没有被缓存是好的&这段代码很少在应用程序中执行。

现在修复SQL注入，我把这段代码改为，

List<PreparedStatement> pStatements = new ArrayList<>();    
for (Object object : objectList) {
    //Create a query which would be different for each object 
    PreparedStatement pStatement =connection.prepareStatement(query);
    // This query can't be added to batch because its a different query so I used list. 
    //Set parameter to pStatement using object 
    pStatements.add(pStatement);
}// Object loop
// In place of statement.executeBatch(); , I had to loop around the list & execute each update separately          
for (PreparedStatement ps : pStatements) {
    ps.executeUpdate();
}

所以你看，我开始创建数千个PreparedStatement对象，然后最终不能利用批处理，因为我的场景要求-有数千个UPDATE或INSERT查询，所有这些查询碰巧是不同的。

在不降低性能的情况下修复SQL注入是强制性的，我认为在这种情况下使用PreparedStatement是不可能的。

另外，当你使用内置的批处理工具时，你必须担心只关闭一个语句，但使用这个List方法，你需要在重用之前关闭语句，重用一个PreparedStatement

PreparedStatement的优点:

Precompilation and DB-side caching of the SQL statement leads to overall faster execution and the ability to reuse the same SQL statement in batches. Automatic prevention of SQL injection attacks by builtin escaping of quotes and other special characters. Note that this requires that you use any of the PreparedStatement setXxx() methods to set the values preparedStatement = connection.prepareStatement("INSERT INTO Person (name, email, birthdate, photo) VALUES (?, ?, ?, ?)"); preparedStatement.setString(1, person.getName()); preparedStatement.setString(2, person.getEmail()); preparedStatement.setTimestamp(3, new Timestamp(person.getBirthdate().getTime())); preparedStatement.setBinaryStream(4, person.getPhoto()); preparedStatement.executeUpdate(); and thus don't inline the values in the SQL string by string-concatenating. preparedStatement = connection.prepareStatement("INSERT INTO Person (name, email) VALUES ('" + person.getName() + "', '" + person.getEmail() + "'"); preparedStatement.executeUpdate(); Eases setting of non-standard Java objects in a SQL string, e.g. Date, Time, Timestamp, BigDecimal, InputStream (Blob) and Reader (Clob). On most of those types you can't "just" do a toString() as you would do in a simple Statement. You could even refactor it all to using PreparedStatement#setObject() inside a loop as demonstrated in the utility method below: public static void setValues(PreparedStatement preparedStatement, Object... values) throws SQLException { for (int i = 0; i < values.length; i++) { preparedStatement.setObject(i + 1, values[i]); } } Which can be used as below: preparedStatement = connection.prepareStatement("INSERT INTO Person (name, email, birthdate, photo) VALUES (?, ?, ?, ?)"); setValues(preparedStatement, person.getName(), person.getEmail(), new Timestamp(person.getBirthdate().getTime()), person.getPhoto()); preparedStatement.executeUpdate();

语句是静态的，准备语句是动态的。

Statement适用于DDL, prepared Statement适用于DML。

语句较慢，而准备语句较快。

更多差异(存档)