1、利用BeanUtils的前提得要加入以下两个jar包：
commons-beanutils-1.8.0.jar
commons-logging-1.1.1.jar
package com.shellway.jdbcDAO;
import java.util.List;
import org.junit.Test;
public class TestDAO {
DAO dao = new DAO();
@Test
public void testUpdate() throws Exception {
String sql = "update examstudent set grade=? where flow_id=12345";
dao.update(sql, 88);
}
@Test
public void test() throws Exception {
String sql = "select flow_id flowID,type,id_card idCard, "
+ "exam_card examCard,student_name studentName,location,grade "
+ "from examstudent where flow_id = ? ";
Student stu = dao.get(Student.class, sql, 12345);
System.out.println(stu);
}
@Test
public void testGetSome() throws Exception {
String sql = "select flow_id flowID,type,id_card idCard, "
+ "exam_card examCard,student_name studentName,location,grade "
+ "from examstudent";
List<Student> students = dao.getForList(Student.class, sql);
System.out.println(students);
}
@Test
public void testGetForValue() throws Exception {
String sql = "select grade from examstudent where flow_id = ? ";
Object obj = dao.getforvalue(sql, 123456);
System.out.println(obj);
}
}
测试类
package com.shellway.jdbcDAO;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.PreparedStatement;
import java.sql.ResultSetMetaData;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.commons.beanutils.BeanUtils;
public class DAO {
public void update(String sql, Object... args) throws Exception {
Connection conn = null;
PreparedStatement ps = null;
try {
conn = JDBCTools.getConnection();
ps = conn.prepareStatement(sql);
for (int i = 0; i < args.length; i++) {
ps.setObject(i + 1, args[i]);
}
ps.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCTools.release(null, ps, conn);
}
}
// 获取一个对象通用的方法
public <T> T get(Class<T> clazz, String sql, Object... args)
throws Exception {
T entity = null;
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
conn = JDBCTools.getConnection();
ps = conn.prepareStatement(sql);
for (int i = 0; i < args.length; i++) {
ps.setObject(i + 1, args[i]);
}
rs = ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
Map<String, Object> map = null;
while (rs.next()) {
map = new HashMap<String, Object>();
for (int i = 0; i < rsmd.getColumnCount(); i++) {
String columnLabel = rsmd.getColumnLabel(i + 1);
Object columnValue = rs.getObject(i + 1);
map.put(columnLabel, columnValue);
}
if (map.size() > 0) {
entity = clazz.newInstance();
for (Map.Entry<String, Object> entry : map.entrySet()) {
String label = entry.getKey();
Object value = entry.getValue();
BeanUtils.setProperty(entity, label, value);
}
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCTools.release(rs, ps, conn);
}
return entity;
}
// 获取一组对象通用的方法
public <T> List<T> getForList(Class<T> clazz, String sql, Object... args)
throws Exception {
T entity = null;
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
List<T> result = new ArrayList<T>();
try {
conn = JDBCTools.getConnection();
ps = conn.prepareStatement(sql);
for (int i = 0; i < args.length; i++) {
ps.setObject(i + 1, args[i]);
}
rs = ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
Map<String, Object> map = new HashMap<String, Object>();
while (rs.next()) {
for (int i = 0; i < rsmd.getColumnCount(); i++) {
String columnLabel = rsmd.getColumnLabel(i + 1);
Object columnValue = rs.getObject(i + 1);
map.put(columnLabel, columnValue);
}
list.add(map);
if (list.size() > 0) {
entity = clazz.newInstance();
for (Map<String, Object> ll : list) {
for (Map.Entry<String, Object> entry : ll.entrySet()) {
String label = entry.getKey();
Object value = entry.getValue();
BeanUtils.setProperty(entity, label, value);
}
}
result.add(entity);
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCTools.release(rs, ps, conn);
}
return result;
}
// 获取一个对象中一列的值通用的方法
public <E> E getforvalue(String sql, Object... args) throws Exception {
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
conn = JDBCTools.getConnection();
ps = conn.prepareStatement(sql);
for (int i = 0; i < args.length; i++) {
ps.setObject(i + 1, args[i]);
}
rs = ps.executeQuery();
if (rs.next()) {
return (E) rs.getObject(1);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCTools.release(rs, ps, conn);
}
return null;
}
}
通用的DAO.java
package com.shellway.jdbcDAO;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.sql.PreparedStatement;
public class JDBCTools {
public static <T> T get(Class<T> clazz, String sql, Object... args)
throws Exception {
T entity = null;
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
try {
conn = JDBCTools.getConnection();
ps = conn.prepareStatement(sql);
for (int i = 0; i < args.length; i++) {
ps.setObject(i + 1, args[i]);
}
rs = ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
Map<String, Object> map = new HashMap<String, Object>();
while (rs.next()) {
for (int i = 0; i < rsmd.getColumnCount(); i++) {
String columnLabel = rsmd.getColumnLabel(i + 1);
Object columnValue = rs.getObject(i + 1);
// Object columnValue = rs.getObject(columnLabel);
map.put(columnLabel, columnValue);
}
}
if (map.size() > 0) {
entity = clazz.newInstance();
for (Map.Entry<String, Object> values : map.entrySet()) {
String key = values.getKey();
Object value = values.getValue();
ReflectionUtils.setFieldValue(entity, key, value);
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCTools.release(rs, ps, conn);
}
return entity;
}
public static void update(String sql, Object... args) throws Exception {
Connection conn = null;
PreparedStatement ps = null;
try {
conn = JDBCTools.getConnection();
ps = conn.prepareStatement(sql);
for (int i = 0; i < args.length; i++) {
ps.setObject(i + 1, args[i]);
}
System.out.println(sql);
ps.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCTools.release(null, ps, conn);
}
}
public static Connection getConnection() throws Exception {
Properties proper = new Properties();
InputStream in = JDBCTools.class.getClassLoader().getResourceAsStream(
"jdbc.properties");
proper.load(in);
String driverClass = proper.getProperty("driver");
String jdbcUrl = proper.getProperty("jdbcUrl");
String user = proper.getProperty("user");
String password = proper.getProperty("password");
Class.forName(driverClass);
Connection connection = DriverManager.getConnection(jdbcUrl, user,
password);
return connection;
}
public static void release(ResultSet rs, Statement state, Connection conn)
throws Exception {
if (rs != null) {
try {
rs.close();
} catch (Exception e) {
e.printStackTrace();
}
}
if (state != null) {
try {
state.close();
} catch (Exception e) {
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
JDBCTools工具类
driver=com.mysql.jdbc.Driver jdbcUrl=jdbc:mysql://localhost:3306/test user=root password=123
配置文件jdbc.properties
package com.shellway.jdbc;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
/**
* 反射的 Utils 函数集合 提供访问私有变量, 获取泛型类型 Class, 提取集合中元素属性等 Utils 函数
*
* @author Administrator
*
*/
public class ReflectionUtils {
/**
* 通过反射, 获得定义 Class 时声明的父类的泛型参数的类型 如: public EmployeeDao extends
* BaseDao<Employee, String>
*
* @param clazz
* @param index
* @return
*/
@SuppressWarnings("unchecked")
public static Class getSuperClassGenricType(Class clazz, int index) {
Type genType = clazz.getGenericSuperclass();
if (!(genType instanceof ParameterizedType)) {
return Object.class;
}
Type[] params = ((ParameterizedType) genType).getActualTypeArguments();
if (index >= params.length || index < 0) {
return Object.class;
}
if (!(params[index] instanceof Class)) {
return Object.class;
}
return (Class) params[index];
}
/**
* 通过反射, 获得 Class 定义中声明的父类的泛型参数类型 如: public EmployeeDao extends
* BaseDao<Employee, String>
*
* @param <T>
* @param clazz
* @return
*/
@SuppressWarnings("unchecked")
public static <T> Class<T> getSuperGenericType(Class clazz) {
return getSuperClassGenricType(clazz, 0);
}
/**
* 循环向上转型, 获取对象的 DeclaredMethod
*
* @param object
* @param methodName
* @param parameterTypes
* @return
*/
public static Method getDeclaredMethod(Object object, String methodName,
Class<?>[] parameterTypes) {
for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass
.getSuperclass()) {
try {
// superClass.getMethod(methodName, parameterTypes);
return superClass.getDeclaredMethod(methodName, parameterTypes);
} catch (NoSuchMethodException e) {
// Method 不在当前类定义, 继续向上转型
}
// ..
}
return null;
}
/**
* 使 filed 变为可访问
*
* @param field
*/
public static void makeAccessible(Field field) {
if (!Modifier.isPublic(field.getModifiers())) {
field.setAccessible(true);
}
}
/**
* 循环向上转型, 获取对象的 DeclaredField
*
* @param object
* @param filedName
* @return
*/
public static Field getDeclaredField(Object object, String filedName) {
for (Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass
.getSuperclass()) {
try {
return superClass.getDeclaredField(filedName);
} catch (NoSuchFieldException e) {
// Field 不在当前类定义, 继续向上转型
}
}
return null;
}
/**
* 直接调用对象方法, 而忽略修饰符(private, protected)
*
* @param object
* @param methodName
* @param parameterTypes
* @param parameters
* @return
* @throws InvocationTargetException
* @throws IllegalArgumentException
*/
public static Object invokeMethod(Object object, String methodName,
Class<?>[] parameterTypes, Object[] parameters)
throws InvocationTargetException {
Method method = getDeclaredMethod(object, methodName, parameterTypes);
if (method == null) {
throw new IllegalArgumentException("Could not find method ["
+ methodName + "] on target [" + object + "]");
}
method.setAccessible(true);
try {
return method.invoke(object, parameters);
} catch (IllegalAccessException e) {
System.out.println("不可能抛出的异常");
}
return null;
}
/**
* 直接设置对象属性值, 忽略 private/protected 修饰符, 也不经过 setter
*
* @param object
* @param fieldName
* @param value
*/
public static void setFieldValue(Object object, String fieldName,
Object value) {
Field field = getDeclaredField(object, fieldName);
if (field == null)
throw new IllegalArgumentException("Could not find field ["
+ fieldName + "] on target [" + object + "]");
makeAccessible(field);
try {
field.set(object, value);
} catch (IllegalAccessException e) {
System.out.println("不可能抛出的异常");
}
}
/**
* 直接读取对象的属性值, 忽略 private/protected 修饰符, 也不经过 getter
*
* @param object
* @param fieldName
* @return
*/
public static Object getFieldValue(Object object, String fieldName) {
Field field = getDeclaredField(object, fieldName);
if (field == null)
throw new IllegalArgumentException("Could not find field ["
+ fieldName + "] on target [" + object + "]");
makeAccessible(field);
Object result = null;
try {
result = field.get(object);
} catch (IllegalAccessException e) {
System.out.println("不可能抛出的异常");
}
return result;
}
}
反射工具类：ReflectionUtils.java 也可通过它代替BeanUtils的setProperty()给对象赋值然后返回该对象
2、获取数据库中的一些元数据：
@Test
public void testDatebaseMetaData() throws Exception {
Connection conn = null;
ResultSet rs = null;
try {
conn = JDBCTools.getConnection();
DatabaseMetaData dbmd = conn.getMetaData();
// 得到数据库的一些基本信息
int version = dbmd.getDatabaseMajorVersion();
System.out.println(version);
String user = dbmd.getUserName();
System.out.println(user);
rs = dbmd.getCatalogs();
while (rs.next()) {
String str = rs.getString(1);
System.out.println(str);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCTools.release(rs, null, conn);
}
}
通过DatabaseMetaData dbmd = conn.getMetaData();获取
3、获取插入记录的主键值，在加入购物车时用到
@Test
public void testPrimeryKey() throws Exception {
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
String sql = "insert into customer(name,email,birth) values(?,?,?) ";
try {
conn = JDBCTools.getConnection();
ps = conn.prepareStatement(sql, ps.RETURN_GENERATED_KEYS);
ps.setString(1, "BBBB");
ps.setString(2, "[email protected]");
ps.setDate(3, new Date(new java.util.Date().getTime()));
ps.executeUpdate();
rs = ps.getGeneratedKeys();
if (rs.next()) {
Object obj = rs.getObject(1);
System.out.println(obj);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCTools.release(null, ps, conn);
}
}
获取最新插入记录的主键值
时间： 2024-10-03 04:04:01