简单实现Spring IOC （单例模式）（解析XML方式）

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.spring.xml</groupId>
  <artifactId>ioc</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>ioc</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
    <!--定义Spring版本号-->
    <org.springframework.version>4.3.7.RELEASE</org.springframework.version>
  </properties>

  <dependencies>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>dom4j</groupId>
      <artifactId>dom4j</artifactId>
      <version>1.6.1</version>
    </dependency>

    <!-- spring start -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aspects</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context-support</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-expression</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-instrument</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-instrument-tomcat</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jms</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-messaging</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-orm</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-oxm</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc-portlet</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-websocket</artifactId>
      <version>${org.springframework.version}</version>
    </dependency>
    <!-- spring end -->
  </dependencies>

  <build>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.0.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.7.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.20.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-jar-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
package com.spring.xml.bean;

public class Car {
    private String name;
    private int price;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getPrice() {
        return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    @Override
    public String toString() {
        return "Car{" +
                "name='" + name + ''' +
                ", price=" + price +
                '}';
    }
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="car" class="com.spring.xml.bean.Car">
        <property name="name" value="BMW"/>
        <property name="price" value="100"/>
    </bean>

    <bean id="car1" class="com.spring.xml.bean.Car">
        <property name="name" value="ChangCheng"/>
        <property name="price" value="101"/>
    </bean>
</beans>

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
package com.spring.xml.utils;

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.springframework.util.ResourceUtils;

import java.io.File;
import java.io.FileNotFoundException;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.*;

/**
 * 1、解析xml文件
 * 2、获取xml文件所有的节点内容
 * 3、根据类路径反射类
 * 4、注入属性信息
 */
public class XmlApplicationContext {
    // xml路径
    private String xmlPath;
    // 存放bean
    private Map<String, Object> map = null;
    // 存放从xml解析出来的类的需要注入的属性名和属性值
    private List<String> propertyName = new ArrayList<>();
    private List<Object> propertyData = new ArrayList<>();

    public XmlApplicationContext(String xmlPath) {
        this.xmlPath = xmlPath;
        try {
            getAllElements();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    // 1、读取xml文件,返回根节点
    public Iterator readXML() throws DocumentException, FileNotFoundException {
        SAXReader reader = new SAXReader();
        File file = ResourceUtils.getFile("classpath:" + xmlPath);
        Document document = reader.read(file);
        Element rootElement = document.getRootElement();
        Iterator iterator = rootElement.elementIterator();
        return iterator;
    }

    // 2、获取xml文件所有的节点内容
    public void getAllElements() throws Exception {
        Iterator iterator = readXML();
        List<Class> classList = new ArrayList<>();
        List<String> idList = new ArrayList<>();
        Class clazz = null;

        while (iterator.hasNext()) {
            Element bean = (Element) iterator.next();
            //System.out.println(next.getName())
            // 获取bean的id,class
            Iterator beanAttributes = bean.attributeIterator();
            String id = null;
            while (beanAttributes.hasNext()) {
                Attribute attribute = (Attribute) beanAttributes.next();
                String classPropertyName = attribute.getName();
                String className = (String) attribute.getData();
                if (classPropertyName.equals("class")) {
                    clazz = Class.forName(className);
                } else
                    id = className;

            }
            // System.out.println(id);
            idList.add(id);
            // 获取类的属性
            Iterator properties = bean.elementIterator();
            while (properties.hasNext()) {
                Element element = (Element) properties.next();
                Iterator propertyAttributes = element.attributeIterator();
                while (propertyAttributes.hasNext()) {
                    Attribute attribute = (Attribute) propertyAttributes.next();
                    String attributeName = attribute.getName();
                    Object attributeData = attribute.getData();
                    propertyName.add(attributeName);
                    propertyData.add(attributeData);
                }
            }
            classList.add(clazz);
        }
        setBeanMap(idList, classList);
    }


    // 反射，依赖注入
    public Object[] getClass(List<Class> classList) throws Exception {
        Object[] objects = new Object[classList.size()];
        int i = 0;
        int j = 0;
        for (Class clazz : classList) {
            Object o = clazz.newInstance();
            Method[] methods = clazz.getDeclaredMethods();
            for (Method method : methods) {
                String methodName = method.getName();
                //System.out.println(methodName);
                if ("set".equals(methodName.substring(0, 3))) {
                    String name = propertyName.get(i);
                    Object data = propertyData.get(i);
                    String field = (String) data;
                    if (name.equals("name")) {
                        data = "set" + ((String) data).substring(0, 1).toUpperCase() + ((String) data).substring(1, ((String) data).length());
                    } else if (name.equals("value")) {

                    } else
                        continue;

                    String name1 = propertyName.get(i + 1);
                    Object data1 = propertyData.get(i + 1);

                    // 依赖注入
                    if (methodName.equals(data)) {
                        Field field1 = clazz.getDeclaredField(field);
                        Class<?> type = field1.getType();
                        String typeName = type.getName();
                        if ("int".equals(typeName))
                            data1 = Integer.valueOf((String) data1);
                        method.invoke(o, data1);
                    }
                    i += 2;
                }
            }
            objects[j] = o;
            j++;
            //System.out.println(o);
        }
        return objects;

    }

    public void setBeanMap(List<String> idList, List<Class> classList) throws Exception {
        map = new HashMap<>();
        Object[] objects = getClass(classList);
        for (int i = 0; i < objects.length; i++) {
            map.put(idList.get(i), objects[i]);
        }
    }

    public Object getBean(String beanName) {
        if (!map.isEmpty())
            return map.get(beanName);
        return null;
    }

    public Map getBeanMap() {
        return map;
    }


}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
package com.spring.xml;

import com.spring.xml.bean.Car;
import com.spring.xml.utils.XmlApplicationContext;
import java.util.Map;

/**
 * Hello world!
 */
public class App {
    public static void main(String[] args) {
        XmlApplicationContext context  = new XmlApplicationContext("applicationContext.xml");
        Car car = (Car)context.getBean("car");
        System.out.println(car);
        Map map = context.getBeanMap();
        System.out.println(map);
    }
}