Hessian入门

1）引入jar包

<!-- https://mvnrepository.com/artifact/com.caucho/hessian -->
        <dependency>
            <groupId>com.caucho</groupId>
            <artifactId>hessian</artifactId>
            <version>4.0.51</version>
        </dependency>

2）创建服务接口

import java.io.File;
import java.util.List;

public interface HelloSessian {

    String sayHello(String name);
    
    List<Exam> getExams();
    
    File download(String path);
    
    String upload(File file);
}

3）写实现类，其中对象要实现序列化接口，因为hessian传递的是二进制流

import java.io.File;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class HelloSessianImpl implements HelloSessian {

    @Override
    public String sayHello(String name) {
        return "Hello " + name;
    }

    @Override
    public List<Exam> getExams() {
        List<Exam> exams = new ArrayList<>();
        Exam e1 = new Exam();
        e1.setId(1001);
        e1.setName("yyq");
        e1.setStart(new Date());
        Exam e2 = new Exam();
        e2.setId(1002);
        e2.setName("lucy");
        e2.setStart(new Date());
        exams.add(e1);
        exams.add(e2);
        return exams;
    }

    @Override
    public File download(String path) {
        return new File(path);
    }

    @Override
    public String upload(File file) {
        String name = file.getName();
        return "Upload " + name + " ok!";
    }

}

import java.io.Serializable;
import java.util.Date;

public class Exam implements Serializable {
    /**serialVersionUID:(用一句话描述这个变量表示什么). 
     */  
    private static final long serialVersionUID = 1L;

    private int id;
    private String name;
    private Date start;
    
    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

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

    public Date getStart() {
        return start;
    }

    public void setStart(Date start) {
        this.start = start;
    }

    @Override
    public String toString() {
        return "Exam [id=" + id + ", name=" + name + ", start=" + start + "]";
    }
}

4）配置servlet

<servlet>
        <servlet-name>hessian</servlet-name>
        <servlet-class>com.caucho.hessian.server.HessianServlet</servlet-class>
        <init-param>
            <param-name>home-api</param-name>
            <param-value>henu.yyq.hessian.HelloSessian</param-value>
        </init-param>
        <init-param>
            <param-name>home-class</param-name>
            <param-value>henu.yyq.hessian.HelloSessianImpl</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>hessian</servlet-name>
        <url-pattern>/hessian</url-pattern>
    </servlet-mapping>

5）部署并且启动tomcat，不解释

6）客户端调用

客户端引入jar包，记得版本要一致

写调用测试类

public static void main(String[] args) throws IOException {
        
        HessianProxyFactory factory = new HessianProxyFactory();
        factory.setOverloadEnabled(true);
        HelloSessian proxy = (HelloSessian) factory.create(HelloSessian.class, "http://localhost:8080/hessian");
        String ret = proxy.sayHello("test");
        System.out.println(ret);
        List<Exam> exams = proxy.getExams();
        for (Exam exam : exams) {
            System.out.println(exam.toString());
        }
        
        File download = proxy.download("d:/1.txt");
        System.out.println(download.getName());
        FileInputStream in = new FileInputStream(download);
        byte[] buf = new byte[1024];
        in.read(buf);
        System.out.println(new String(buf));
        in.close();
        
//        proxy.upload(file)
    }

 结果：

Hello test
Exam [id=1001, name=yyq, start=Tue May 01 23:48:14 CST 2018]
Exam [id=1002, name=lucy, start=Tue May 01 23:48:14 CST 2018]
1.txt
哈哈哈
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