代码语言：javascript复制
public class MyTest {
public static void test01() throws ClassNotFoundException, SQLException, IllegalAccessException, InstantiationException {
String driverClass = "com.mysql.jdbc.Driver";
String jdbcUrl = "jdbc:mysql://localhost:3306/myemployees?useUnicode=true&useSSL=false";
String user = "root";
String password = "abcd123456";
ResultSet resultSet = null;
Class.forName(driverClass);
Connection connection = DriverManager.getConnection(jdbcUrl,user,password);
String sql = "SELECT flow_id flowId, type, id_card idCard, "
"exam_card examCard, student_name studentName, "
"location, grade " "FROM examstudent WHERE flow_id = ?";
PreparedStatement preparedStatement = connection.prepareStatement(sql);
preparedStatement.setInt(1,3);
resultSet = preparedStatement.executeQuery();
Map<String,Object> values = new HashMap<>();
ResultSetMetaData rsmd = resultSet.getMetaData();
while (resultSet.next()){
for(int i = 0; i < rsmd.getColumnCount();i ){
String columnLabel = rsmd.getColumnLabel(i 1);
Object columnValue = resultSet.getObject(columnLabel);
values.put(columnLabel,columnValue);
}
}
Class clazz = Student.class;
Object object = clazz.newInstance();
for(Map.Entry<String,Object> entry : values.entrySet()){
String fieldName = entry.getKey();
Object fieldValue = entry.getValue();
ReflectionUtils.setFieldValue(object,fieldName,fieldValue);
}
System.out.println(object);
resultSet.close();
preparedStatement.close();
connection.close();
}
public static void main(String[] args) {
try {
test01();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
}
}
}//Student类
public class Student {
private long flowId;
private Integer type;
private String idCard;
private String examCard;
private String studentName;
private String location;
private Integer grade;
public long getFlowId() {
return flowId;
}
public int getGrade() {
return grade;
}
public int getType() {
return type;
}
public String getExamCard() {
return examCard;
}
public String getLocation() {
return location;
}
public String getIdCard() {
return idCard;
}
public String getStudentName() {
return studentName;
}
public void setExamCard(String examCard) {
this.examCard = examCard;
}
public void setFlowId(int flowId) {
this.flowId = flowId;
}
public void setIdCard(String idCard) {
this.idCard = idCard;
}
public void setGrade(int grade) {
this.grade = grade;
}
public void setLocation(String location) {
this.location = location;
}
public void setStudentName(String studentName) {
this.studentName = studentName;
}
public void setType(int type) {
this.type = type;
}
@Override
public String toString() {
return "Student{"
"flowId=" flowId
", type=" type
", idCard='" idCard '''
", examCard='" examCard '''
", studentName='" studentName '''
", location='" location '''
", grade=" grade
'}';
}
public Student(int flowId, int type, String idCard, String examCard,
String studentName, String location, int grade) {
super();
this.flowId = flowId;
this.type = type;
this.idCard = idCard;
this.examCard = examCard;
this.studentName = studentName;
this.location = location;
this.grade = grade;
}
public Student() {
}
}CREATE TABLE IF NOT EXISTS `examstudent`(`flow_id` INT UNSIGNED AUTO_INCREMENT, `type` INT NOT NULL, `id_card` VARCHAR(40) NOT NULL, `exam_card` VARCHAR(40) NOT NULL, `student_name` VARCHAR(40) NOT NULL, `location` VARCHAR(40) NOT NULL, `grade` INT NOT NULL, PRIMARY KEY ( `flow_id` ) )ENGINE=InnoDB DEFAULT CHARSET=utf8;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");
} catch (Exception e){
System.out.println(e);
}
}
/**
* 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;
}
}
