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本文出自【DylanAndroid的博客】

玩转JDBC打造数据库操作万能工具类JDBCUtil，加入了高效的数据库连接池，利用了参数绑定有效防止SQL注入

在之前学习了MySQL和Oracle之后，那么，如和在Java种去连接这两种数据库。在这个轻量级的工具类当中，使用了数据库连接池

去提高数据库连接的高效性，并且使用了PreparedStatement来执行对SQL的预编译，能够有效防止SQL注入问题。

一.准备在配置文件配置:配置数据库连接属性文件：在项目新建config包下建立jdbc-mysql.properties并加入以下配置

jdbc.driverClassName=com.mysql.jdbc.Driverjdbc.url=jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf8jdbc.username=rootjdbc.password=root

二.准备数据库连接池对象：单例

package util;import com.mchange.boPooledDataSource;import com.mchange.v2.c3p0.DataSources;import java.beans.PropertyVetoException;import java.io.FileInputStream;import java.io.IOException;import java.sql.Connection;import java.sql.SQLException;import java.util.Properties;/*** 数据库连接对象* Created by yuandl on -12-16.*/public class DBConnectionPool {private static volatile DBConnectionPool dbConnection;private ComboPooledDataSource cpds;/*** 在构造函数初始化的时候获取数据库连接*/private DBConnectionPool() {try {/**通过属性文件获取数据库连接的参数值**/Properties properties = new Properties();FileInputStream fileInputStream = new FileInputStream("src/config/jdbc-mysql.properties");properties.load(fileInputStream);/**获取属性文件中的值**/String driverClassName = properties.getProperty("jdbc.driverClassName");String url = properties.getProperty("jdbc.url");String username = properties.getProperty("jdbc.username");String password = properties.getProperty("jdbc.password");/**数据库连接池对象**/cpds = new ComboPooledDataSource();/**设置数据库连接驱动**/cpds.setDriverClass(driverClassName);/**设置数据库连接地址**/cpds.setJdbcUrl(url);/**设置数据库连接用户名**/cpds.setUser(username);/**设置数据库连接密码**/cpds.setPassword(password);/**初始化时创建的连接数,应在minPoolSize与maxPoolSize之间取值.默认为3**/cpds.setInitialPoolSize(3);/**连接池中保留的最大连接数据.默认为15**/cpds.setMaxPoolSize(10);/**当连接池中的连接用完时，C3PO一次性创建新的连接数目;**/cpds.setAcquireIncrement(1);/**隔多少秒检查所有连接池中的空闲连接,默认为0表示不检查;**/cpds.setIdleConnectionTestPeriod(60);/**最大空闲时间,超过空闲时间的连接将被丢弃.为0或负数据则永不丢弃.默认为0;**/cpds.setMaxIdleTime(3000);/**因性能消耗大请只在需要的时候使用它。如果设为true那么在每个connection提交的时候都将校验其有效性。建议使用idleConnectionTestPeriod或automaticTestTable等方法来提升连接测试的性能。Default: false**/cpds.setTestConnectionOnCheckout(true);/**如果设为true那么在取得连接的同时将校验连接的有效性。Default: false **/cpds.setTestConnectionOnCheckin(true);/**定义在从数据库获取新的连接失败后重复尝试获取的次数，默认为30;**/cpds.setAcquireRetryAttempts(30);/**两次连接中间隔时间默认为1000毫秒**/cpds.setAcquireRetryDelay(1000);/** 获取连接失败将会引起所有等待获取连接的线程异常,但是数据源仍有效的保留,并在下次调用getConnection()的时候继续尝试获取连接.如果设为true,那么尝试获取连接失败后该数据源将申明已经断开并永久关闭.默认为false**/cpds.setBreakAfterAcquireFailure(true);} catch (IOException e) {e.printStackTrace();} catch (PropertyVetoException e) {e.printStackTrace();}}/*** 获取数据库连接对象，单例** @return*/public static DBConnectionPool getInstance() {if (dbConnection == null) {synchronized (DBConnectionPool.class) {if (dbConnection == null) {dbConnection = new DBConnectionPool();}}}return dbConnection;}/*** 获取数据库连接** @return 数据库连接*/public final synchronized Connection getConnection() throws SQLException {return cpds.getConnection();}/*** finalize()方法是在垃圾收集器删除对象之前对这个对象调用的。** @throws Throwable*/protected void finalize() throws Throwable {DataSources.destroy(cpds);super.finalize();}}

三.实现新增、修改、删除、查询操作的两个核心方法：可以实现任何复杂的SQL,而且通过数据绑定的方式不会有SQL注入问题

/*** 可以执行新增，修改，删除** @param sqlsql语句* @param bindArgs 绑定参数* @return 影响的行数* @throws SQLException SQL异常*/public static int executeUpdate(String sql, Object[] bindArgs) throws SQLException {/**影响的行数**/int affectRowCount = -1;Connection connection = null;PreparedStatement preparedStatement = null;try {/**从数据库连接池中获取数据库连接**/connection = DBConnectionPool.getInstance().getConnection();/**执行SQL预编译**/preparedStatement = connection.prepareStatement(sql.toString());/**设置不自动提交，以便于在出现异常的时候数据库回滚**/connection.setAutoCommit(false);System.out.println(getExecSQL(sql, bindArgs));if (bindArgs != null) {/**绑定参数设置sql占位符中的值**/for (int i = 0; i < bindArgs.length; i++) {preparedStatement.setObject(i + 1, bindArgs[i]);}}/**执行sql**/affectRowCount = preparedStatement.executeUpdate();mit();String operate;if (sql.toUpperCase().indexOf("DELETE FROM") != -1) {operate = "删除";} else if (sql.toUpperCase().indexOf("INSERT INTO") != -1) {operate = "新增";} else {operate = "修改";}System.out.println("成功" + operate + "了" + affectRowCount + "行");System.out.println();} catch (Exception e) {if (connection != null) {connection.rollback();}e.printStackTrace();throw e;} finally {if (preparedStatement != null) {preparedStatement.close();}if (connection != null) {connection.close();}}return affectRowCount;}/*** 执行查询** @param sql要执行的sql语句* @param bindArgs 绑定的参数* @return List<Map<String, Object>>结果集对象* @throws SQLException SQL执行异常*/public static List<Map<String, Object>> executeQuery(String sql, Object[] bindArgs) throws SQLException {List<Map<String, Object>> datas = new ArrayList<>();Connection connection = null;PreparedStatement preparedStatement = null;ResultSet resultSet = null;try {/**获取数据库连接池中的连接**/connection = DBConnectionPool.getInstance().getConnection();preparedStatement = connection.prepareStatement(sql);if (bindArgs != null) {/**设置sql占位符中的值**/for (int i = 0; i < bindArgs.length; i++) {preparedStatement.setObject(i + 1, bindArgs[i]);}}System.out.println(getExecSQL(sql, bindArgs));/**执行sql语句，获取结果集**/resultSet = preparedStatement.executeQuery();getDatas(resultSet);System.out.println();} catch (Exception e) {e.printStackTrace();throw e;} finally {if (resultSet != null) {resultSet.close();}if (preparedStatement != null) {preparedStatement.close();}if (connection != null) {connection.close();}}return datas;}

四.执行新增的简化操作

/*** 执行数据库插入操作** @param valueMap 插入数据表中key为列名和value为列对应的值的Map对象* @param tableName 要插入的数据库的表名* @return 影响的行数* @throws SQLException SQL异常*/public static int insert(String tableName, Map<String, Object> valueMap) throws SQLException {/**获取数据库插入的Map的键值对的值**/Set<String> keySet = valueMap.keySet();Iterator<String> iterator = keySet.iterator();/**要插入的字段sql，其实就是用key拼起来的**/StringBuilder columnSql = new StringBuilder();/**要插入的字段值，其实就是？**/StringBuilder unknownMarkSql = new StringBuilder();Object[] bindArgs = new Object[valueMap.size()];int i = 0;while (iterator.hasNext()) {String key = iterator.next();columnSql.append(i == 0 ? "" : ",");columnSql.append(key);unknownMarkSql.append(i == 0 ? "" : ",");unknownMarkSql.append("?");bindArgs[i] = valueMap.get(key);i++;}/**开始拼插入的sql语句**/StringBuilder sql = new StringBuilder();sql.append("INSERT INTO ");sql.append(tableName);sql.append(" (");sql.append(columnSql);sql.append(" ) VALUES (");sql.append(unknownMarkSql);sql.append(" )");return executeUpdate(sql.toString(), bindArgs);}

五.执行更新的简化操作

/*** 执行更新操作** @param tableName 表名* @param valueMap 要更改的值* @param whereMap 条件* @return 影响的行数* @throws SQLException SQL异常*/public static int update(String tableName, Map<String, Object> valueMap, Map<String, Object> whereMap) throws SQLException {/**获取数据库插入的Map的键值对的值**/Set<String> keySet = valueMap.keySet();Iterator<String> iterator = keySet.iterator();/**开始拼插入的sql语句**/StringBuilder sql = new StringBuilder();sql.append("UPDATE ");sql.append(tableName);sql.append(" SET ");/**要更改的的字段sql，其实就是用key拼起来的**/StringBuilder columnSql = new StringBuilder();int i = 0;List<Object> objects = new ArrayList<>();while (iterator.hasNext()) {String key = iterator.next();columnSql.append(i == 0 ? "" : ",");columnSql.append(key + " = ? ");objects.add(valueMap.get(key));i++;}sql.append(columnSql);/**更新的条件:要更改的的字段sql，其实就是用key拼起来的**/StringBuilder whereSql = new StringBuilder();int j = 0;if (whereMap != null && whereMap.size() > 0) {whereSql.append(" WHERE ");iterator = whereMap.keySet().iterator();while (iterator.hasNext()) {String key = iterator.next();whereSql.append(j == 0 ? "" : " AND ");whereSql.append(key + " = ? ");objects.add(whereMap.get(key));j++;}sql.append(whereSql);}return executeUpdate(sql.toString(), objects.toArray());}

六.执行删除的简化操作

/*** 执行删除操作** @param tableName 要删除的表名* @param whereMap 删除的条件* @return 影响的行数* @throws SQLException SQL执行异常*/public static int delete(String tableName, Map<String, Object> whereMap) throws SQLException {/**准备删除的sql语句**/StringBuilder sql = new StringBuilder();sql.append("DELETE FROM ");sql.append(tableName);/**更新的条件:要更改的的字段sql，其实就是用key拼起来的**/StringBuilder whereSql = new StringBuilder();Object[] bindArgs = null;if (whereMap != null && whereMap.size() > 0) {bindArgs = new Object[whereMap.size()];whereSql.append(" WHERE ");/**获取数据库插入的Map的键值对的值**/Set<String> keySet = whereMap.keySet();Iterator<String> iterator = keySet.iterator();int i = 0;while (iterator.hasNext()) {String key = iterator.next();whereSql.append(i == 0 ? "" : " AND ");whereSql.append(key + " = ? ");bindArgs[i] = whereMap.get(key);i++;}sql.append(whereSql);}return executeUpdate(sql.toString(), bindArgs);}

七.查询的4种玩法

1.执行sql通过 Map

import util.DBUtil;import java.sql.SQLException;import java.util.Date;import java.util.HashMap;import java.util.List;import java.util.Map;/*** Created by yuandl on -12-16.*/public class DBTest {public static void main(String[] args) {System.out.println("数据库的原数据");testQuery3();testInsert();System.out.println("执行插入后的数据");testQuery3();testUpdate();System.out.println("执行修改后的数据");testQuery3();testDelete();System.out.println("执行删除后的数据");testQuery3();System.out.println("带条件的查询1");testQuery2();System.out.println("带条件的查询2");testQuery1();}/*** 测试插入*/private static void testInsert() {Map<String, Object> map = new HashMap<>();map.put("emp_id", 1013);map.put("name", "JDBCUtil测试");map.put("job", "developer");map.put("salary", 10000);map.put("hire_date", new java.sql.Date(System.currentTimeMillis()));try {int count = DBUtil.insert("emp_test", map);} catch (SQLException e) {e.printStackTrace();}}/*** 测试更新*/private static void testUpdate() {Map<String, Object> map = new HashMap<>();map.put("name", "测试更新");Map<String, Object> whereMap = new HashMap<>();whereMap.put("emp_id", "1013");try {int count = DBUtil.update("emp_test", map, whereMap);} catch (SQLException e) {e.printStackTrace();}}/*** 测试删除*/private static void testDelete() {Map<String, Object> whereMap = new HashMap<>();whereMap.put("emp_id", 1013);whereMap.put("job", "developer");try {int count = DBUtil.delete("emp_test", whereMap);} catch (SQLException e) {e.printStackTrace();}}/*** 查询方式一*/public static void testQuery1() {Map<String,Object> whereMap=new HashMap<>();whereMap.put("salary","10000");try {DBUtil.query("emp_test",whereMap);} catch (SQLException e) {e.printStackTrace();}}/*** 查询方式二*/public static void testQuery2() {String where = "job = ? AND salary = ? ";String[] whereArgs = new String[]{"clerk", "3000"};try {List<Map<String, Object>> list = DBUtil.query("emp_test", where, whereArgs);} catch (SQLException e) {e.printStackTrace();}}/*** 查询方式三*/public static void testQuery3() {try {List<Map<String, Object>> list = DBUtil.query("emp_test", false, null, null, null, null, null, null, null);} catch (SQLException e) {e.printStackTrace();}}}

打印结果

数据库的原数据SELECT * FROM emp_test成功查询到了14行数据第1行：{DEPT_TEST_ID=10, EMP_ID=1001, SALARY=10000, HIRE_DATE=-01-12, BONUS=2000, MANAGER=1005, JOB=Manager, NAME=张无忌}第2行：{DEPT_TEST_ID=10, EMP_ID=1002, SALARY=8000, HIRE_DATE=-01-12, BONUS=1000, MANAGER=1001, JOB=Analyst, NAME=刘苍松}第3行：{DEPT_TEST_ID=10, EMP_ID=1003, SALARY=9000, HIRE_DATE=-02-11, BONUS=1000, MANAGER=1001, JOB=Analyst, NAME=李翊}第4行：{DEPT_TEST_ID=10, EMP_ID=1004, SALARY=5000, HIRE_DATE=-02-11, BONUS=null, MANAGER=1001, JOB=Programmer, NAME=郭芙蓉}第5行：{DEPT_TEST_ID=20, EMP_ID=1005, SALARY=15000, HIRE_DATE=-02-15, BONUS=null, MANAGER=null, JOB=President, NAME=张三丰}第6行：{DEPT_TEST_ID=20, EMP_ID=1006, SALARY=5000, HIRE_DATE=-02-01, BONUS=400, MANAGER=1005, JOB=Manager, NAME=燕小六}第7行：{DEPT_TEST_ID=20, EMP_ID=1007, SALARY=3000, HIRE_DATE=-02-01, BONUS=500, MANAGER=1006, JOB=clerk, NAME=陆无双}第8行：{DEPT_TEST_ID=30, EMP_ID=1008, SALARY=5000, HIRE_DATE=-05-01, BONUS=500, MANAGER=1005, JOB=Manager, NAME=黄蓉}第9行：{DEPT_TEST_ID=30, EMP_ID=1009, SALARY=4000, HIRE_DATE=-02-20, BONUS=null, MANAGER=1008, JOB=salesman, NAME=韦小宝}第10行：{DEPT_TEST_ID=30, EMP_ID=1010, SALARY=4500, HIRE_DATE=-05-10, BONUS=500, MANAGER=1008, JOB=salesman, NAME=郭靖}第11行：{DEPT_TEST_ID=null, EMP_ID=1011, SALARY=null, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=于泽成}第12行：{DEPT_TEST_ID=null, EMP_ID=1012, SALARY=null, HIRE_DATE=-08-10, BONUS=null, MANAGER=null, JOB=null, NAME=amy}第13行：{DEPT_TEST_ID=null, EMP_ID=1014, SALARY=8000, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=张无忌}第14行：{DEPT_TEST_ID=20, EMP_ID=1015, SALARY=null, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=刘苍松}INSERT INTO emp_test (name,hire_date,job,salary,emp_id ) VALUES (JDBCUtil测试,-12-17,developer,10000,1013 )成功新增了1行执行插入后的数据SELECT * FROM emp_test成功查询到了15行数据第1行：{DEPT_TEST_ID=10, EMP_ID=1001, SALARY=10000, HIRE_DATE=-01-12, BONUS=2000, MANAGER=1005, JOB=Manager, NAME=张无忌}第2行：{DEPT_TEST_ID=10, EMP_ID=1002, SALARY=8000, HIRE_DATE=-01-12, BONUS=1000, MANAGER=1001, JOB=Analyst, NAME=刘苍松}第3行：{DEPT_TEST_ID=10, EMP_ID=1003, SALARY=9000, HIRE_DATE=-02-11, BONUS=1000, MANAGER=1001, JOB=Analyst, NAME=李翊}第4行：{DEPT_TEST_ID=10, EMP_ID=1004, SALARY=5000, HIRE_DATE=-02-11, BONUS=null, MANAGER=1001, JOB=Programmer, NAME=郭芙蓉}第5行：{DEPT_TEST_ID=20, EMP_ID=1005, SALARY=15000, HIRE_DATE=-02-15, BONUS=null, MANAGER=null, JOB=President, NAME=张三丰}第6行：{DEPT_TEST_ID=20, EMP_ID=1006, SALARY=5000, HIRE_DATE=-02-01, BONUS=400, MANAGER=1005, JOB=Manager, NAME=燕小六}第7行：{DEPT_TEST_ID=20, EMP_ID=1007, SALARY=3000, HIRE_DATE=-02-01, BONUS=500, MANAGER=1006, JOB=clerk, NAME=陆无双}第8行：{DEPT_TEST_ID=30, EMP_ID=1008, SALARY=5000, HIRE_DATE=-05-01, BONUS=500, MANAGER=1005, JOB=Manager, NAME=黄蓉}第9行：{DEPT_TEST_ID=30, EMP_ID=1009, SALARY=4000, HIRE_DATE=-02-20, BONUS=null, MANAGER=1008, JOB=salesman, NAME=韦小宝}第10行：{DEPT_TEST_ID=30, EMP_ID=1010, SALARY=4500, HIRE_DATE=-05-10, BONUS=500, MANAGER=1008, JOB=salesman, NAME=郭靖}第11行：{DEPT_TEST_ID=null, EMP_ID=1011, SALARY=null, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=于泽成}第12行：{DEPT_TEST_ID=null, EMP_ID=1012, SALARY=null, HIRE_DATE=-08-10, BONUS=null, MANAGER=null, JOB=null, NAME=amy}第13行：{DEPT_TEST_ID=null, EMP_ID=1014, SALARY=8000, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=张无忌}第14行：{DEPT_TEST_ID=20, EMP_ID=1015, SALARY=null, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=刘苍松}第15行：{DEPT_TEST_ID=null, EMP_ID=1013, SALARY=10000, HIRE_DATE=-12-17, BONUS=null, MANAGER=null, JOB=developer, NAME=JDBCUtil测试}UPDATE emp_test SET name = 测试更新 WHERE emp_id = 1013 成功修改了1行执行修改后的数据SELECT * FROM emp_test成功查询到了15行数据第1行：{DEPT_TEST_ID=10, EMP_ID=1001, SALARY=10000, HIRE_DATE=-01-12, BONUS=2000, MANAGER=1005, JOB=Manager, NAME=张无忌}第2行：{DEPT_TEST_ID=10, EMP_ID=1002, SALARY=8000, HIRE_DATE=-01-12, BONUS=1000, MANAGER=1001, JOB=Analyst, NAME=刘苍松}第3行：{DEPT_TEST_ID=10, EMP_ID=1003, SALARY=9000, HIRE_DATE=-02-11, BONUS=1000, MANAGER=1001, JOB=Analyst, NAME=李翊}第4行：{DEPT_TEST_ID=10, EMP_ID=1004, SALARY=5000, HIRE_DATE=-02-11, BONUS=null, MANAGER=1001, JOB=Programmer, NAME=郭芙蓉}第5行：{DEPT_TEST_ID=20, EMP_ID=1005, SALARY=15000, HIRE_DATE=-02-15, BONUS=null, MANAGER=null, JOB=President, NAME=张三丰}第6行：{DEPT_TEST_ID=20, EMP_ID=1006, SALARY=5000, HIRE_DATE=-02-01, BONUS=400, MANAGER=1005, JOB=Manager, NAME=燕小六}第7行：{DEPT_TEST_ID=20, EMP_ID=1007, SALARY=3000, HIRE_DATE=-02-01, BONUS=500, MANAGER=1006, JOB=clerk, NAME=陆无双}第8行：{DEPT_TEST_ID=30, EMP_ID=1008, SALARY=5000, HIRE_DATE=-05-01, BONUS=500, MANAGER=1005, JOB=Manager, NAME=黄蓉}第9行：{DEPT_TEST_ID=30, EMP_ID=1009, SALARY=4000, HIRE_DATE=-02-20, BONUS=null, MANAGER=1008, JOB=salesman, NAME=韦小宝}第10行：{DEPT_TEST_ID=30, EMP_ID=1010, SALARY=4500, HIRE_DATE=-05-10, BONUS=500, MANAGER=1008, JOB=salesman, NAME=郭靖}第11行：{DEPT_TEST_ID=null, EMP_ID=1011, SALARY=null, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=于泽成}第12行：{DEPT_TEST_ID=null, EMP_ID=1012, SALARY=null, HIRE_DATE=-08-10, BONUS=null, MANAGER=null, JOB=null, NAME=amy}第13行：{DEPT_TEST_ID=null, EMP_ID=1014, SALARY=8000, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=张无忌}第14行：{DEPT_TEST_ID=20, EMP_ID=1015, SALARY=null, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=刘苍松}第15行：{DEPT_TEST_ID=null, EMP_ID=1013, SALARY=10000, HIRE_DATE=-12-17, BONUS=null, MANAGER=null, JOB=developer, NAME=测试更新}DELETE FROM emp_test WHERE job = developer AND emp_id = 1013 成功删除了1行执行删除后的数据SELECT * FROM emp_test成功查询到了14行数据第1行：{DEPT_TEST_ID=10, EMP_ID=1001, SALARY=10000, HIRE_DATE=-01-12, BONUS=2000, MANAGER=1005, JOB=Manager, NAME=张无忌}第2行：{DEPT_TEST_ID=10, EMP_ID=1002, SALARY=8000, HIRE_DATE=-01-12, BONUS=1000, MANAGER=1001, JOB=Analyst, NAME=刘苍松}第3行：{DEPT_TEST_ID=10, EMP_ID=1003, SALARY=9000, HIRE_DATE=-02-11, BONUS=1000, MANAGER=1001, JOB=Analyst, NAME=李翊}第4行：{DEPT_TEST_ID=10, EMP_ID=1004, SALARY=5000, HIRE_DATE=-02-11, BONUS=null, MANAGER=1001, JOB=Programmer, NAME=郭芙蓉}第5行：{DEPT_TEST_ID=20, EMP_ID=1005, SALARY=15000, HIRE_DATE=-02-15, BONUS=null, MANAGER=null, JOB=President, NAME=张三丰}第6行：{DEPT_TEST_ID=20, EMP_ID=1006, SALARY=5000, HIRE_DATE=-02-01, BONUS=400, MANAGER=1005, JOB=Manager, NAME=燕小六}第7行：{DEPT_TEST_ID=20, EMP_ID=1007, SALARY=3000, HIRE_DATE=-02-01, BONUS=500, MANAGER=1006, JOB=clerk, NAME=陆无双}第8行：{DEPT_TEST_ID=30, EMP_ID=1008, SALARY=5000, HIRE_DATE=-05-01, BONUS=500, MANAGER=1005, JOB=Manager, NAME=黄蓉}第9行：{DEPT_TEST_ID=30, EMP_ID=1009, SALARY=4000, HIRE_DATE=-02-20, BONUS=null, MANAGER=1008, JOB=salesman, NAME=韦小宝}第10行：{DEPT_TEST_ID=30, EMP_ID=1010, SALARY=4500, HIRE_DATE=-05-10, BONUS=500, MANAGER=1008, JOB=salesman, NAME=郭靖}第11行：{DEPT_TEST_ID=null, EMP_ID=1011, SALARY=null, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=于泽成}第12行：{DEPT_TEST_ID=null, EMP_ID=1012, SALARY=null, HIRE_DATE=-08-10, BONUS=null, MANAGER=null, JOB=null, NAME=amy}第13行：{DEPT_TEST_ID=null, EMP_ID=1014, SALARY=8000, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=张无忌}第14行：{DEPT_TEST_ID=20, EMP_ID=1015, SALARY=null, HIRE_DATE=null, BONUS=null, MANAGER=null, JOB=null, NAME=刘苍松}带条件的查询1SELECT * FROM emp_test WHERE job = clerk AND salary = 3000 成功查询到了1行数据第1行：{DEPT_TEST_ID=20, EMP_ID=1007, SALARY=3000, HIRE_DATE=-02-01, BONUS=500, MANAGER=1006, JOB=clerk, NAME=陆无双}带条件的查询2SELECT * FROM emp_test WHERE salary = 10000 成功查询到了1行数据第1行：{DEPT_TEST_ID=10, EMP_ID=1001, SALARY=10000, HIRE_DATE=-01-12, BONUS=2000, MANAGER=1005, JOB=Manager, NAME=张无忌}

十.GitHub

玩转JDBC打造数据库操作万能工具类JDBCUtil 加入了高效的数据库连接池 利用了参数绑定有效防止SQL注入